2-Butanol
2-Butanol, or sec-butanol, is an organic compound with formula CH3CH(OH)CH2CH3. This secondary alcohol is a flammable, colorless liquid that is soluble in three parts water and completely miscible with organic solvents. It is produced on a large scale, primarily as a precursor to the industrial solvent methyl ethyl ketone. 2-Butanol is chiral and thus can be obtained as either of two stereoisomers designated as (R)-(−)-2-butanol and (S)-(+)-2-butanol. It is normally encountered as a 1:1 mixture of the two stereoisomers — a racemic mixture.


2-Butanol, Manufacture and applications
2-Butanol is manufactured industrially by the hydration of 1-butene or 2-butene:


2-Butanol, Manufacture and applications
Sulfuric acid is used as a catalyst for this conversion.


2-Butanol, Manufacture and applications
In the laboratory it can be prepared via Grignard reaction by reacting ethylmagnesium bromide with acetaldehyde in dried diethyl ether or tetrahydrofuran.


2-Butanol, Manufacture and applications
Although some 2-butanol is used as a solvent, it is mainly converted to butanone (methyl ethyl ketone, MEK), an important industrial solvent and found in many domestic cleaning agents and paint removers. Though most paint removers have ceased using MEK in their products due to health concerns and new laws. Volatile esters of 2-butanol have pleasant aromas and are used in small amounts as perfumes or in artificial flavors.


2-Butanol, Solubility
The listed solubility of 2-butanol is often incorrect, including some of the most well-known references such as the Merck Index, the CRC Handbook of Chemistry and Physics, and Lange's Handbook of Chemistry. Even the International Programme on Chemical Safety lists the wrong solubility. This widespread error originated because of Beilstein's Handbuch der Organischen Chemie (Handbook of Organic Chemistry). This work cites a false solubility of 12.5 g/100 g water. Many other sources used this solubility, which has snowballed into a widespread error in the industrial world. The correct data (35.0 g/100 g at 20 °C, 29 g/100 g at 25 °C, and 22 g/100 g at 30 °C) were first published in 1886 by Alexejew and then similar data was reported by other scientists including Dolgolenko and Dryer in 1907 and 1913, respectively.


2-Butanol, Precautions
Like other butanols, 2-butanol has low acute toxicity. The LD50 is 4400 mg/kg (rat, oral).


2-Butanol, Precautions
Several explosions have been reported during the conventional distillation of 2-butanol, apparently due to the buildup of peroxides with the boiling point higher than that of pure alcohol (and therefore concentrating in the still pot during distillation). As alcohols, unlike ethers, are not widely known to be capable of forming peroxide impurities, the danger is likely to be overlooked. 2-Butanol is in Class B Peroxide Forming Chemicals


2-Butene
2-Butene is an acyclic alkene with four carbon atoms. It is the simplest alkene exhibiting cis/trans-isomerism (also known as (E/Z)-isomerism); that is, it exists as two geometric isomers cis-2-butene ((Z)-2-butene) and trans-2-butene ((E)-2-butene).


2-Butene
It is a petrochemical, produced by the catalytic cracking of crude oil or the dimerization of ethylene. Its main uses are in the production of gasoline (petrol) and butadiene, although some 2-butene is also used to produce the solvent butanone via hydration to 2-butanol followed by oxidation.


2-Butene
The two isomers are extremely difficult to separate by distillation because of the proximity of their boiling points (~4 °C for cis and ~1 °C for trans). However, separation is unnecessary in most industrial settings, as both isomers behave similarly in most of the desired reactions. A typical industrial 2-butene mixture is 70% (Z)-2-butene (cis-isomer) and 30% (E)-2-butene (trans-isomer). Butane and 1-butene are common impurities, present at 1% or more in industrial mixtures, which also contain smaller amounts of isobutene, butadiene and butyne.


2-Butoxyethanol
2-Butoxyethanol is an organic compound with the chemical formula BuOC2H4OH (Bu = CH3CH2CH2CH2). This colorless liquid has a sweet, ether-like odor, as it derives from the family of glycol ethers, and is a butyl ether of ethylene glycol. As a relatively nonvolatile, inexpensive solvent, it is used in many domestic and industrial products because of its properties as a surfactant. It is a known respiratory irritant and can be acutely toxic but animal studies did not find it to be mutagenic, and no studies suggest it is a human carcinogen. A study of 13 classroom air contaminants conducted in Portugal reported a statistically significant association with increased rates of nasal obstruction, the study also reported a positive association below the level of statistical significance with a higher risk of obese asthma and increased child BMI.


2-Butoxyethanol, Production
2-Butoxyethanol is commonly obtained through two processes; the ethoxylation reaction of butanol and ethylene oxide in the presence of a catalyst:


2-Butoxyethanol, Production
or the etherification of butanol with 2-chloroethanol. 2-Butoxyethanol can be obtained in the laboratory by performing a ring opening of 2-propyl-1,3-dioxolane with boron trichloride. It is often produced industrially by combining ethylene glycol and butyraldehyde in a Parr reactor with palladium on carbon.


2-Butoxyethanol, Production
In 2006, the European production of butyl glycol ethers amounted to 181 kilotons, of which approximately 50% (90 kt/a) was 2-butoxyethanol. World production is estimated to be 200 to 500 kt/a, of which 75% is for paints and coatings and 18% for metal cleaners and household cleaners. In the US, it is considered a High Production Volume Chemical because greater than 100 million pounds of this chemical are produced per year.


2-Butoxyethanol, Uses
2-Butoxyethanol is a glycol ether with modest surfactant properties, which can also be used as a mutual solvent. In use since the 1930s, glycol ethers are solvents that dissolve both water-soluble and hydrophobic substances. Glycol ethers consist of two components, an alcohol and ether. According to the nature of alcohol, molecules of this class can be divided into two groups: E series and P series which correspond to ethylene and propylene respectively. Glycol ethers are selected for specific purposes, such as solubility, inflammability, and volatility.


2-Butoxyethanol, Uses, Commercial uses
2-Butoxyethanol is a solvent for paints and surface coatings, as well as cleaning products and inks. Products that contain 2-butoxyethanol include acrylic resin formulations, asphalt release agents, firefighting foam, leather protectors, oil spill dispersants, degreaser applications, photographic strip solutions, whiteboard cleaners, liquid soaps, cosmetics, dry cleaning solutions, lacquers, varnishes, herbicides, latex paints, enamels, printing paste, and varnish removers, and silicone caulk. Products containing this compound are commonly found at construction sites, automobile repair shops, print shops, and facilities that produce sterilizing and cleaning products. It is the main ingredient of many home, commercial and industrial cleaning solutions. Since the molecule has both non-polar and polar ends, butoxyethanol is useful for removing both polar and non-polar substances, like grease and oils. It is also approved by the U.S. FDA to be used as direct and indirect food additives, which include antimicrobial agents, defoamers, stabilizers, and adhesives.


2-Butoxyethanol, Uses, In the petroleum industry
2-Butoxyethanol is commonly produced for the oil industry because of its surfactant properties.


2-Butoxyethanol, Uses, In the petroleum industry
In the petroleum industry, 2-butoxyethanol is a component of fracturing fluids, drilling stabilizers, and oil slick dispersants for both water-based and oil-based hydraulic fracturing. When liquid is pumped into the well, the fracturing fluids are pumped under extreme pressure, so 2-butoxyethanol is used to stabilize them by lowering the surface tension. As a surfactant, 2-butoxyethanol adsorbs at the oil-water interface of the fracture. The compound is also used to facilitate the release of the gas by preventing congealing. It is also used as a crude oil-water coupling solvent for more general oil well workovers. Because of its surfactant properties, it is a major constituent (30–60% w/w) in the oil spill dispersant Corexit 9527, which was widely used in the aftermath of the 2010 Deepwater Horizon oil spill.


2-Butoxyethanol, Safety
2-Butoxyethanol has a low acute toxicity, with LD50 of 2.5 g/kg in rats. Laboratory tests by the U. S. National Toxicology Program have shown that only sustained exposure to high concentrations (100-500 ppm) of 2-butoxyethanol can cause adrenal tumors in animals. American Conference of Governmental Industrial Hygienists (ACGIH) reports that 2-butoxyethanol is carcinogenic in rodents. These rodent tests may not directly translate to carcinogenicity in humans, as the observed mechanism of cancer involves the rodents' forestomach, which humans lack. OSHA does not regulate 2-butoxyethanol as a carcinogen. 2-Butoxyethanol has not been shown to penetrate shale rock in a study conducted by Manz.


2-Butoxyethanol, Safety, Disposal and degradation
2-Butoxyethanol can be disposed of by incineration. It was shown that disposal occurs faster in the presence of semiconductor particles. 2-Butoxyethanol usually decomposes in the presence of air within a few days by reacting with oxygen radicals. It has not been identified as a major environmental contaminant, nor is it known to bio-accumulate. 2-Butoxyethanol biodegrades in soils and water, with a half life of 1–4 weeks in aquatic environments.


2-Butoxyethanol, Safety, Human exposure
2-butoxyethanol most commonly enters the human body system through dermal absorption, inhalation, or oral consumption of the chemical. The ACGIH threshold limit value (TLV) for worker exposure is 20 ppm, which is well above the odor detection threshold of 0.4 ppm. Blood or urine concentrations of 2-butoxyethanol or the metabolite 2-butoxyacetic acid may be measured using chromatographic techniques. A biological exposure index of 200 mg 2-butoxyacetic acid per g creatinine has been established in an end-of-shift urine specimen for U.S. employees. 2-Butoxyethanol and its metabolites fall to undetectable levels in urine after about 30 hours in human males.


2-Butoxyethanol, Safety, Animal studies
Harmful effects have been observed in nonhuman mammals exposed to high levels of 2-butoxyethanol. Developmental effects were seen in a study that exposed pregnant Fischer 344 rats, a type of laboratory rat, and New Zealand white rabbits to varying doses of 2-butoxyethanol. At 100 ppm (483 mg/m3) and 200 ppm (966 mg/m3) exposure, statistically significant increases were observed in the number of litters with skeletal defects. Additionally, 2-butoxyethanol was associated with a significant decrease in maternal body weight, uterine weight, and number of total implants. 2-Butoxyethanol is metabolized in mammals by the enzyme alcohol dehydrogenase.


2-Butoxyethanol, Safety, Animal studies
Neurological effects have also been observed in animals exposed to 2-butoxyethanol. Fischer 344 rats exposed to 2-butoxyethanol at concentrations of 523 ppm and 867 ppm experienced decreased coordination. Male rabbits showed a loss of coordination and equilibrium after exposure to 400 ppm of 2-butoxyethanol for two days.


2-Butoxyethanol, Safety, Animal studies
When exposed to 2-butoxyethanol in drinking water, both F344/N rats and B63F1 mice showed negative effects. The range of exposure for the two species was between 70 mg/kg body weight per day to 1300 mg/kg body weight per day. Decreased body weight and water consumption were seen for both species. Rats had reduced red blood cell counts and thymus weights, as well as lesions in the liver, spleen, and bone marrow.


2-Butoxyethanol, Safety, Regulation in Canada
Environment and Health Canada recommended that 2-butoxyethanol  be added to Schedule 1 of the Canadian Environmental Protection Act, 1999 (CEPA). Under these regulations, products containing 2-butoxyethanol are to be diluted below a certain concentration. Only those in which the user performs the required dilution are required to include it on labelling information.


2-Butoxyethanol, Safety, Regulation in the US
2-Butoxyethanol is listed in California as a hazardous substance and the state sets an 8 hour average airborne concentration exposure limit at 25 ppm, and in California employers are required to inform employees when they are working with it.


2-Butoxyethanol, Safety, Regulation in the US
It is approved by the Food and Drug Administration as "an indirect and direct food additive for use as an antimicrobial agent, defoamer, stabilizer and component of adhesives", and also "may be used to wash or assist in the peeling of fruits and vegetables" and "may be safely used as components of articles intended for use in packaging, transporting & holding food".


2-Butoxyethanol, Safety, Regulation in the US
After it was deleted from a UN list of substances requiring special toxicity labeling in 1994, and a subsequent petition by the American Chemistry Council, 2-butoxyethanol was removed from the U.S. Environmental Protection Agency's list of hazardous air pollutants in 2004. The safety of products containing 2-butoxyethanol as normally used is defended by the industry trade groups the American Chemistry Council and the Soap and Detergent Association.


2-Butoxyethanol acetate
2-Butoxyethanol acetate is a chemical commonly used as a solvent; it is the acetate of 2-butoxyethanol.


2-Butoxyethanol acetate, Applications
2-Butoxyethanol acetate is used in a variety of industries as a solvent for nitrocellulose and multicolored lacquers, varnishes, enamels, and epoxy resin. It is useful as a solvent because of its high boiling point. It is also used in the manufacture of polyvinyl acetate latex. It is an ingredient in ink removers and spot removers.


2-Butoxyethanol acetate, Safety
It will react strongly with oxidizers. Its safety profile is similar to 2-butoxyethanol.


2-Butoxyethanol acetate, Safety
People can be exposed to 2-butoxyethanol acetate in the workplace by breathing it in, swallowing it, skin absorption, or eye contact. Symptoms of exposure include irritation of the eyes, skin, nose, and throat, hemolysis (bursting of red blood cells), hematuria (blood in the urine), central nervous system depression, headache, and vomiting. Chronic exposure can cause kidney damage, liver damage, and blood disease. People who work in printing, silk-screening, automobile repair, spray-painting, and furniture production may be exposed to 2-butoxyethanol acetate in the workplace.


2-Butoxyethanol acetate, Safety
People who do not work with 2-butoxyethanol acetate can be exposed to it in small amounts by touching or breathing in fumes from household cleaners.


2-Butyne
2-Butyne (dimethylacetylene, crotonylene or but-2-yne) is an alkyne with chemical formula CH3C≡CCH3. Produced artificially, it is a colorless, volatile, pungent liquid at standard temperature and pressure.


2-Butyne
2-Butyne is of interest to physical chemists because of its very low torsional barrier and the problem of determining that barrier using high-resolution infrared spectroscopy. Analysis of its spectrumleads to a determination that the torsional barrier is only 6 cm−1 (1.2×10−22 J or 72 J mol−1). However, it has not been determined whether the equilibrium structure is eclipsed (D3h) or staggered (D3d). Symmetry analysis using the Molecular Symmetry Group G36 shows that one would need to analyse its high resolution rotation-vibration Raman spectrum to determine its equilibrium structure.


2-Butyne
2-Butyne (dimethylethyne) forms with 5-decyne (dibutylethyne), 4-octyne (dipropylethyne) and 3-hexyne (diethylethyne) a group of symmetric alkynes.


2-Butyne, Synthesis
2-Butyne can be synthesized by the rearrangement of ethylacetylene in a solution of ethanolic potassium hydroxide.


2-Butyne, Applications
2-Butyne, along with propyne, is used to synthesize alkylated hydroquinones in the total synthesis of Vitamin E.


2-C-Methyl-D-erythritol-2,4-cyclopyrophosphate
2-C-Methyl-d-erythritol-2,4-cyclopyrophosphate (MEcPP) (also 2-C-Methyl-d-erythritol-2,4-cyclodiphosphate) is an intermediate in the MEP pathway (non-mevalonate) of isoprenoid precursor biosynthesis. MEcPP is produced by MEcPP synthase (IspF) and is a substrate for HMB-PP synthase (IspG).


2-C-Methyl-D-erythritol-2,4-cyclopyrophosphate
Under conditions of oxidative stress, MEcPP accumulates in certain bacteria. MEcPP releases histone-like proteins from DNA, triggering nucleoid decondensation in Chlamydia trachomatis during the process of terminal differentiation. Abiotic stresses to plants, including wounding and excessive high-light exposure, lead to an increase in MEcPP accumulation in chloroplasts. Transported from the chloroplast to the plant cell nucleus, MEcPP engages in retrograde signalling that leads to the specific induction of nuclear-encoded stress-response genes.


2-C-Methylerythritol 4-phosphate
2-C-Methyl-D-erythritol 4-phosphate (MEP) is an intermediate on the MEP pathway (non-mevalonate pathway) of isoprenoid precursor biosynthesis. It is the first committed metabolite on that pathway on the route to IPP and DMAPP.


2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase
2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase (MEcPP synthase, IspF, EC ) is a zinc-dependent enzyme which participates in the MEP pathway (non-mevalonate pathway) of isoprenoid precursor biosynthesis. It catalyzes the chemical reaction:


2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase
Hence, this enzyme has one substrate, 4-diphosphocytidyl-2-C-methyl-D-erythritol 2-phosphate (CDP-MEP), and two products, 2-C-methyl-D-erythritol 2,4-cyclodiphosphate (MEcPP) and CMP.


2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase
The enzyme is considered a phosphorus-oxygen lyase. The systematic name of this enzyme class is 2-phospho-4-(cytidine 5'-diphospho)-2-C-methyl-D-erythritol CMP-lyase (cyclizing; 2-C-methyl-D-erythritol 2,4-cyclodiphosphate-forming). Other names in common use include IspF, YgbB and MEcPP synthase.


2-C-methyl-D-erythritol 2,4-cyclodiphosphate synthase, Structural studies
As of late 2007, 20 structures have been solved for this class of enzymes, with PDB accession codes , , , , , , , , , , , , , , , , , , , and .


2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase
In enzymology, a 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase (EC ) is an enzyme that catalyzes the chemical reaction:


2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase
Thus, the two substrates of this enzyme are CTP and 2-C-methyl-D-erythritol 4-phosphate, whereas its two products are diphosphate and 4-diphosphocytidyl-2-C-methylerythritol.


2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase
This enzyme belongs to the family of transferases, specifically those transferring phosphorus-containing nucleotide groups (nucleotidyltransferases).


2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase
This enzyme participates in isoprenoid biosynthesis and stenvenosim. It catalyzes the third step of the MEP pathway; the formation of CDP-ME (4-diphosphocytidyl-2C-methyl-D-erythritol) from CTP and MEP (2C-methyl-D-erythritol 4-phosphate). The isoprenoid pathway is a well known target for anti-infective drug development.


2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase, Nomenclature
The systematic name of this enzyme class is CTP:2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase. This enzyme is also called:


2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase, Nomenclature
It is normally abbreviated IspD. It is also referenced by the open reading frame YgbP.


2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase, Structural studies
The crystal structure of the E. coli 2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase ,  & , reported by Richard et al. (2001), was the first one for an enzyme involved in the MEP pathway.


2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase, Structural studies
As of February 2010, 13 other structures have been solved for this class of enzymes, with PDB accession codes , , , , , , , , ,, ,  and .


2-C-methyl-D-erythritol 4-phosphate cytidylyltransferase, Further reading
This EC 2.7 enzyme-related article is a stub. You can help Wikipedia by .


2-Carbomethoxytropinone
2-Carbomethoxytropinone (2-CMT) is a commonly used organic intermediate in the synthesis of cocaine and its analogues. As of at least 1999 no reaction pathway has been discovered that synthesizes cocaine-like compounds without utilizing the reduction of 2-CMT. The structure of cocaine was discovered by Richard Willstätter in 1898 after he synthesized it from 2-carbomethoxytropinone. Although it was originally believed that 2-CMT in nature was ultimately derived from ornithine and acetic acid, subsequent research has indicated other pathways exist for the biosynthesis of 2-CMT. A β-keto ester, 2-CMT exists in equilibrium with its keto–enol tautomer.


2-Carbomethoxytropinone, Synthesis
2-CMT (3) can be synthesized from 1,3-acetonedicarboxylate anhydride (1) by methanolysis followed by reaction with methylamine and succinaldehyde.


2-Carboxy-D-arabinitol-1-phosphatase
2-carboxy-D-arabinitol-1-phosphatase (also called CA1Pase; EC ) is an enzyme that catalyzes the chemical reaction


2-Carboxy-D-arabinitol-1-phosphatase
Thus, the two substrates of this enzyme are 2-carboxy-D-arabinitol 1-phosphate and H2O, whereas its two products are 2-carboxy-D-arabinitol and phosphate.


2-Carboxy-D-arabinitol-1-phosphatase
This enzyme belongs to the family of hydrolases, to be specific, those acting on phosphoric monoester bonds. The systematic name of this enzyme class is 2-carboxy-D-arabinitol-1-phosphate 1-phosphohydrolase.


2-Carboxy-D-arabinitol-1-phosphatase, In biology
The best-studied 2-Carboxy-D-arabinitol-1-phosphate phosphatase is the enzyme that inactivates the RuBisCO inhibitor 2-carboxy-D-arabinitol-1-phosphate (CA1P).


2-Carboxy-D-arabinitol-1-phosphatase, In biology
When light levels are high, the inactivation occurs after CA1P has been released from RuBisCO by RuBisCO activase. As CA1P is present in many but not all plants, CA1P-mediated regulation of RuBisCO is not universal for all photosynthetic life. Amino acid sequences of the CA1Pase enzymes from wheat, French bean, tobacco, and Arabidopsis reveal that the enzymes contain 2 different domains, indicating that it is a multifunctional enzyme.


2-Carboxy-D-arabinitol-1-phosphatase, In biology
CA1Pase enzyme activity varies between different species due to their regulation by different redox-active compounds, such as glutathione. However, it is yet to be determined whether this process occurs in vivo. Wheat CA1Pase heterologously expressed in E. coli is also able to dephosphorylate the RuBisCO inhibitor D-glycero-2,3-diulose-1,5-bisphosphate.


2-Carboxy-D-arabitinol 1-phosphate
2-Carboxy-D-arabitinol 1-phosphate (or CA1P) is a molecule produced in plants that inhibits the production of RuBisCO, a key enzyme in the Calvin cycle and carbon fixation. In dark conditions, this molecule binds to RuBisCO, preventing it from participating in chemical reactions. As the amount of light present increases, CA1P levels decrease, freeing RuBisCO's reactive ends, allowing more of the molecules to participate in chemical reactions. It can be broken down by the enzyme 2-carboxy-D-arabinitol-1-phosphatase into 2-carboxy-D-arabinitol.


2-Carboxybenzaldehyde
2-Carboxybenzaldehyde is a chemical compound. It consists of a benzene ring, with an aldehyde and a carboxylic acid as substituents that are ortho to each other. The compound exhibits ring–chain tautomerism: the two substituents can react with each other to form 3-hydroxyphthalide, a cyclic lactol. This lactol reacts readily with Grignard reagents , forming alkyl- and aryl-substituted phthalides. Other benzo-fused heterocyclic compounds can be derived from 2-carboxybenzaldehyde, including isoindolinones and phthalazinones, with a variety of pharmacological properties, such as the antihistamine azelastine.


2-Carboxybenzaldehyde, Synthesis
2-Carboxybenzaldehyde was first prepared from phthalide and characterized in 1887. The reaction of bromine with phthalide produces 2-bromophthalide, which is converted into 2-formylbenzoic acid by heating with water in a total yield of 78 to 83%.


2-Carboxybenzaldehyde, Synthesis
An analogous process based on a chlorination reaction can also be used:


2-Carboxybenzaldehyde, Synthesis
The synthesis of 1-dichloromethyl-2-(trichloromethyl)benzene by photochlorination of o-xylene was also reported in 1887.


2-Carboxybenzaldehyde, Synthesis
The hydrolysis of the pentachloroxylene to the 2-carboxybenzaldehyde is carried out by boiling it with FeCl3-containing hydrochloric acid.


2-Carboxybenzaldehyde, Synthesis
In the reaction of phthalic anhydride with sodium tetracarbonylferrate, only one of the carboxyl groups is reduced to the aldehyde, the second remains unchanged.


2-Carboxybenzaldehyde, Synthesis
In a laboratory procedure, the oxidation of naphthalene with alkaline potassium permanganate is given, which, however, yields only a yield of 39% 2-carboxybenzaldehyde. Also the oxidation of naphthalene with ozone to 2-formylbenzoic acid offers no significant advantages.


2-Carboxybenzaldehyde, Properties
Pure 2-carboxybenzaldehyde is a white crystalline powder which dissolves in water and in short-chain alcohols. In solid form and in most solvents, the substance is present as racemic 3-hydroxyphthalide (a lactol) as a result of ring–chain tautomerism.


2-Carboxybenzaldehyde, Properties
The refractive index is  =  1.4500 (at 25 °C, 589 nm).


2-Carboxybenzaldehyde, Application
In the lactol form, 2-carboxybenzaldehyde behaves like a carboxylic acid anhydride and reacts smoothly with alcohols forming 3-alkoxyphthalides.


2-Carboxybenzaldehyde, Application
Also with other nucleophilic compounds, such as, thiols, amines, amides, etc., 3-hydroxyphthalide reacts without a catalyst to give the corresponding derivatives. For example, it reacts with morpholine in 91% yield to 3-morpholinyl phthalide. 3-Hydroxyphthalide reacts with thionyl chloride at the hydroxyl group smoothly (80-90% yield) to 3-chlorophthalide. With Grignard reagents, the hydroxy group can be exchanged for the corresponding alkyl or aryl group:


2-Carboxybenzaldehyde, Application
In the presence of (+)-cinchonine, in the reaction of (racemic) 3-hydroxyphthalide with carboxylic acid anhydrides to the corresponding chiral 3-substituted phthalides an enantiomeric excess of up to 90% ee can be achieved besides high product yields. An alternative approach to (racemic) 3-substituted phthalides with high yields is opened up by the reaction of 2-carboxybenzaldehyde and β-keto acids in the presence of base 4-anisidine in glycerol as solvent.


2-Carboxybenzaldehyde, Application
2-Carboxybenzaldehyde underdoes a double condensation reaction with hydrazine or alkylhydrazines, 1(2H)-phthalenazinones are obtained under acid catalysis with K10-montmorillonite and microwave irradiation in high yield.


2-Carboxybenzaldehyde, Application
Phthalazinones (1(2H)-phthalenazinones) are important building blocks for natural products, fine chemicals and pharmaceutical active ingredients, such as the antihypertensive vasodilator hydralazine.


2-Carboxybenzaldehyde, Application
2-carboxybenzaldehyde can also be used for the preparation of N-substituted isoindolinones (1-isoindolinones, 2,3-dihydroindol-1-ones) which are formed when reacting 2-carboxybenzaldehyde with primary amines in the presence of platinum nanowires and low hydrogen pressure in 1,4-dioxane in very high yields:


2-Carboxybenzaldehyde, Application
When the reaction of 2-carboxybenzaldehyde is carried out with primary amines in the presence of dimethylphosphite, the corresponding isoindolin-1-one-3-phosphonates are obtained first. After activation with butyllithium with aromatic aldehydes (such as, benzaldehyde in a Horner-Wadsworth-Emmons reaction), these can be converted in very high yields to 3-(arylmethylene)isoindolin-1-ones.


2-Carboxybenzaldehyde, Application
More recently, 2-formylbenzoic acid became due to its reactivity of some interest as versatile molecular building block in multicomponent reactions, for example the Ugi reaction, for the synthesis of heterocyclic annellated aromatics. Functionalized isoindolinones are accessible in high yields in a three-component reaction with 2-formylbenzoic acid and 2-bromoanilines by palladium-catalyzed carbonylation.


2-Carboxybenzaldehyde, Application
Another three-component reaction (here carried out as a Strecker synthesis) with 2-carboxybenzaldehyde, primary amines and potassium cyanide in methanol yields in the acidic medium an N-substituted isoindolinone-1-carbonitrile, formally an aminoacetonitrile derivative of isoindolinone with two moles of HCN.


2-Carboxybenzaldehyde, Application
When substituted 2-formylbenzoic acid, potassium cyanide and equimolar amounts of primary aromatic amines and acetic acid are used, substituted isochromes-1-ones (isocumarins, 1H-2-benzopyran-1-ones) are obtained in good yields.


2-Carboxybenzaldehyde, Application
The isochromenones obtained are quantitatively converted into isoindolinones by reacting in DMSO upon ring constriction into substituted isobenzofurans or with catalytic amounts of iodine in triethylamine.


2-Carboxybenzaldehyde, Application
With isonitriles instead of potassium cyanide, 2-carboxybenzaldehyde and primary aromatic amines react in methanol to form substituted isochromen-1-ones, which are converted to isoindolinones with traces of acid.


2-Carboxybenzaldehyde, Application
Synthesis pathways for the isoquinoline derivative quinisocaine (acting as a local anesthetic) and the antihistamine azelastine are also based on 2-carboxybenzaldehyde as starting material.


2-Chloro-1,1,1-trifluoroethane
2-Chloro-1,1,1-trifluoroethane, also known as 1,1,1-trifluoro-2-chloroethane or Freon 133a, is an alkyl halide belonging to the category of chlorofluorocarbons, having chemical formula F3C-CH2-Cl. Under standard conditions it appears as a colorless gas, partially soluble in water. It is used as a refrigerant, as a solvent and as a reagent in organic synthesis.


2-Chloro-9,10-bis(phenylethynyl)anthracene
2-Chloro-9,10-bis(phenylethynyl)anthracene is a fluorescent dye used in lightsticks. It emits green light, used in 12-hour low-intensity Cyalume sticks.


2-Chloro-9,10-diphenylanthracene
2-Chloro-9,10-diphenylanthracene is a fluorescent dye used in glow sticks for a blue-green glow. It is a chlorinated derivative of 9,10-diphenylanthracene.


2-Chloro-m-cresol
2-Chloro-m-cresol is a chlorinated cresol. The compound is difficult to synthesise as chlorination of m-cresol yields the para-product (4-chloro-3-methylphenol). Historically synthesis has been achieved via a para-selective nitration, followed by conversion to a diazonium compound and a Sandmeyer reaction to insert the chlorine into the 2-position.


2-Chlorobenzaldehyde
2-Chlorobenzaldehyde (o-Chlorobenzaldehyde) is a chlorinated derivative of benzaldehyde that is used in production of CS gas. It reacts with malononitrile to form CS.


2-Chlorobenzoic acid
2-Chlorobenzoic acid is an organic compound with the formula ClC6H4CO2H. It is one of three isomeric chlorobenzoic acids, the one that is the strongest acid. This white solid is used as a precursor to a variety of drugs, food additives, and dyes.


2-Chlorobenzoic acid, Synthesis and reactions
It is prepared by the oxidation of 2-chlorotoluene. The laboratory scale reaction employs potassium permanganate. Alternatively it arises by the hydrolysis of α,α,α-trichloro-2-toluene.


2-Chlorobenzoic acid, Synthesis and reactions
The chloride is readily replaced by ammonia to 2-aminobenzoic acid. At elevated temperature it decarboxylates.


2-Chlorobutane
2-Chlorobutane is a compound of chlorine, hydrogen, and carbon. It is also called sec-butyl chloride. It is a colorless, volatile liquid at room temperature that is not miscible in water.


2-Chlorobutane, Physical properties
It is a colorless, volatile liquid at room temperature that is not miscible in water. Being an alkyl chloride, its boiling point varies depending on what kind of halide is attached and where it is attached. The boiling points of chlorides are lower than bromides or iodides due to the small size of chlorine relative to other halogens, and its weaker intermolecular forces.


2-Chlorobutane, Physical properties
Despite its polarity, 2-chlorobutane is only slightly soluble in water due to the hydrocarbon chain its attached to, this makes it soluble in nonpolar-organic solvents. Like many alkyl halides, it is relativity reactive, although not as reactive as iodides and bromides (I>Br>Cl>F), because of this reactivity, alkyl fluorides are more stable than others, and are not readily reactive.


2-Chlorobutane, Synthesis
2-Chlorobutane can be synthesized through the addition of hydrochloric acid to 2-butene in the following reaction:


2-Chlorobutane, Synthesis
The reaction is two-step, with the pi electrons attacking the chloride hydrogen, which forms a chloride nucleophile. In the second step, the nucleophile attacks the carbocation generated in the first step.


2-Chlorobutane, Synthesis
Although addition of a hydrogen halide to an alkene is stereoselective, the symmetrical structure of 2-butene prevents an anti-Marknikov product from forming due to both sides of the double bond having the same stability.


2-Chlorobutane, Synthesis
In addition, 2-chlorobutane can be synthesized in a substitution reaction by reacting 2-butanol with hydrochloric acid.


2-Chlorobutane, Synthesis
In this case, the reaction is SN1 because 2-butanol generates a carbocation in a 2-step reaction. Because a hydroxyl group is not a good leaving group, it first attacks the chloride hydrogen, creating water, which is a good leaving group, this generates the carbocation. In the second step, the chloride nucleophile attacks the carbocation to form the product.


2-Chlorobutane, Synthesis
2-Chlorobutane, along with other alkyl halides, is a useful intermediate in many different organic reactions. The halogen group is an effective leaving group, leading to its use in both elimination and substitution reactions. In addition, the compound is also a candidate for coupling reactions via a Grignard reagent.


2-Chlorobutane, Uses
2-Chlorobutane, along with other alkyl halides, is a useful intermediate in many different organic reactions. The halogen group is an effective leaving group, leading to its use in both elimination and substitution reactions. In addition, the compound is also a candidate for coupling reactions via a Grignard reagent.


2-Chlorobutane, Uses, Substitution reactions
2-Chlorobutane, along with other alkyl halides, is a useful intermediate in many different organic reactions. The halogen group is an effective leaving group, leading to its use in both elimination and substitution reactions. In addition, the compound is also a candidate for coupling reactions via a Grignard reagent. In an Sn2 reaction, a nucleophile (iodine) attacks the partially positive carbon, which eliminates the chlorine. This occurs in one step.


2-Chlorobutane, Uses, Substitution reactions
A less favorable but still possible reaction is an Sn1 reaction, where a secondary carbocation is formed once the leaving group is removed. The nucleophile then attacks the carbocation, forming the product.


2-Chlorobutane, Uses, Elimination reactions
Additionally, because 2-chlorobutane is antiperiplanar, it can undergo E2 elimination reactions with strong bases. In it, the chlorine leaving group is removed, and the double bond is restored to yield different constitutional isomers2. This is because 2-chlorobutane possesses two different sets of β-hydrogens at the first and third carbons respectively, resulting in 1-butene or 2-butene. It is important to note that as a secondary alkyl halide, both E2 and Sn2 reactions are equally likely when reacting with a substance that can act as both a base and a nucleophile. Which reaction occurs is dependent on the surrounding conditions.


2-Chlorobutane, Uses, Elimination reactions
In an E2 mechanism, a strong base (ex. sodium hydroxide) abstracts a beta hydrogen, causing the elections from the former carbon-hydrogen bond to re-form the double bond. This action removes the leaving group, converting 2-chlorobutane to 2-butene or 1-butene depending on which beta hydrogen is removed, because of Zaitsev's rule, the more stable 2-butene product is favored.


2-Chlorobutane, Uses, Grignard reactions
As an alkyl halide, 2-chlorobutane can be used to prepare a Grignard reagent for use in forming a carbon-carbon bond. In the first step, a magnesium ion donates an electron to the alpha carbon in 2-chlorobutane, removing chlorine and forming an allyl radical as well as a Mg+1 radical. In the second step, the Mg+1 radical couples with the allyl radical while the chloride ion interacts with the magnesium ion.


2-Chloroethanesulfonyl chloride
2-Chloroethanesulfonyl chloride is a chemical compound used in the making of other chemicals. It is a severe skin and eye irritant, and can also cause irritation to the nose, throat and lungs when inhaled.


2-Chloroethanol
2-Chloroethanol is a chemical compound with the formula HOCH2CH2Cl and the simplest chlorohydrin. This colorless liquid has a pleasant ether-like odor. It is miscible with water. The molecule is bifunctional, consisting of both an alkyl chloride and an alcohol functional groups.


2-Chloroethanol, Synthesis and applications
2-Chloroethanol was once produced on a large scale as a precursor to ethylene oxide:


2-Chloroethanol, Synthesis and applications
This application has been supplanted by the more economic direct oxidation of ethylene. Otherwise chloroethanol is still used in the production of pharmaceuticals, biocides, and plasticizers. Many of these applications entail its use in installing 2-hydroxyethyl groups. Several dyes are prepared by the alkylation of aniline derivatives with chloroethanol. It is also used for manufacture of thiodiglycol.


2-Chloroethanol, Synthesis and applications
It is a solvent for cellulose acetate and ethyl cellulose, textile printing dyes, in dewaxing, refining of rosin, extraction of pine lignin, and the cleaning of machines.


2-Chloroethanol, Environmental aspects
Chloroethanol is a metabolite in the degradation of 1,2-dichloroethane. The alcohol is then further oxidized via chloroacetaldehyde to chloroacetate. This metabolic pathway is topical since billions of kilograms of 1,2-dichloroethane are processed annually as a precursor to vinyl chloride.


2-Chloroethanol, Safety
2-Chloroethanol is toxic with an LD50 of 89 mg/kg in rats. Like most organochlorine compounds, chloroethanol combusts to yield hydrogen chloride and phosgene.


2-Chloroethanol, Safety
In regards to dermal exposure to 2-chloroethanol, the Occupational Safety and Health Administration has set a permissible exposure limit of 5 ppm (16 mg/m3) over an eight-hour time-weighted average, while the National Institute for Occupational Safety and Health has a more protective recommended exposure limit of a 1 ppm (3 mg/m3) exposure ceiling.


2-Chloroethanol, Safety
It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.


2-Chloroethyl ethyl sulfide
2-Chloroethyl ethyl sulfide is the organosulfur compound with the formula C2H5SC2H4Cl. It is a colorless liquid. The compound, also known as half mustard, has been heavily investigated because of its structural similarity to the sulfur mustard S(C2H4Cl)2. The LD50s of the half and full mustard are 252 and 2.4 mg/kg (oral, rats).


2-Chloromethylpyridine
2-Chloromethylpyridine is an organic compound with the formula ClCH2C5H4N. It is one of three isomeric chloromethylpyridines, the others being 3-chloromethylpyridine and 4-chloromethylpyridine. All are alkylating agents. A colorless solid, 2-chloromethylpyridine is a precursor to pyridine-containing ligands.


2-Chloromethylpyridine, Safety
2-Chloromethylpyridine, an analogue of nitrogen mustards, has been investigated for its mutagenicity.


2-Chloronaphthalene
2-Chloronaphthalene is an organochlorine chemical compound, a chlorinated derivative of naphthalene. Its chemical formula is C10H7Cl. The compound is an isomer for 1-chloronaphthalene.


2-Chloronaphthalene, Synthesis
2-Chloronaphthalene is obtained directly by chlorination of naphthalene, with the formation of more highly substituted derivatives such as dichloro- and trichloronaphthalenes, in addition to the two monochlorinated isomeric compounds: 1-chloronaphthalene and 2-chloronaphthalene.


2-Chloronaphthalene, Properties
2-Chloronaphthalene is a combustible, off-white odorless solid, which is practically insoluble in water. The compound may react with strong oxidizing agents.


2-Chlorophenol
2-Chlorophenol or ortho-chlorophenol is an organic compound with the formula C6H4Cl(OH). It is one of three isomeric monochloride derivatives of phenol. As from occasional use as a disinfectant, it has few  applications. It is an intermediate in the polychlorination of phenol. 2-Chlorophenol is a colorless liquid, although commercial samples are often yellow or amber-colored. It has an unpleasant, penetrating (carbolic) odor. It is poorly soluble in water.


2-Chloropropene
2-Chloropropene is an organochlorine compound with the formula CH2=C(Cl)CH3. It is a colorless gas that condenses just below room temperature. Unlike the closely related vinyl chloride, which is a major industrial chemical, 2-chloropropene has no commercial applications and is a lightly studied compound. In the research laboratory, it is used as a source of the 2-propenyl group. One early synthesis involves dehydrohalogenation of 1,2-dichloropropane with potassium hydroxide.


2-Chloropropionic acid
2-Chloropropionic acid (2-chloropropanoic acid) is the chemical compound with the formula CH3CHClCO2H. This colorless liquid is the simplest chiral chlorocarboxylic acid, and it is noteworthy for being readily available as a single enantiomer. The conjugate base of 2-chloropropionic acid (CH3CHClCO2−), as well as its salts and esters, are known as 2-chloropropionates or 2-chloropropanoates.


2-Chloropropionic acid, Preparation
Racemic 2-chloropropionic acid is produced by chlorination of propionyl chloride followed by hydrolysis of the 2-chloropropionyl chloride. Enantiomerically pure (S)-2-chloropropionic acid can be prepared from L-alanine via diazotization in hydrochloric acid. Other α-amino acids undergo this reaction.


2-Chloropropionic acid, Reactions
Reduction of (S)-2-chloropropionic acid with lithium aluminium hydride affords (S)-2-chloropropanol, the simplest chiral chloro-alcohol. This alcohol undergoes cyclization upon treatment with potassium hydroxide, which causes dehydrohalogenation to give the epoxide, (R)-propylene oxide (methyloxirane).


2-Chloropropionic acid, Reactions
2-Chloropropionyl chloride reacts with isobutylbenzene to give, after hydrolysis, ibuprofen.


2-Chloropropionic acid, Safety
In general, α-halocarboxylic acids and their esters are good alkylating agents and should be handled with care. 2-Chloropropionic acid is a neurotoxin.


2-Chloropyridine
2-Chloropyridine is an organohalide with the formula C5H4ClN. It is a colorless liquid that is mainly used to generate fungicides and insecticides in industry. It also serves to generate antihistamines and antiarrythymics for pharmaceutical purposes.


2-Chloropyridine, Preparation
2-Choropyridine is produced by direct reaction of pyridine with chlorine. The initially formed 2-chloropyridine reacts further to give 2,6-dichloropyridine.


2-Chloropyridine, Preparation
Alternatively, 2-chloropyridines can be conveniently synthesized in high yields from pyridine-N-oxides.


2-Chloropyridine, Preparation
2-Choropyridine was originally prepared by the chlorination of 2-hydroxypyridine with phosphoryl chloride.


2-Chloropyridine, Main reactions and applications
2-Chloropyridine reacts with nucleophiles to generate pyridine derivatives substituted at the second and fourth carbons on the heterocycle. Therefore, many reactions using 2-chloropyridine generate mixtures of products which require further workup to isolate the desired isomer.


2-Chloropyridine, Main reactions and applications
Some commercial products include pyrithione, pyripropoxyfen, chlorphenamine, and disopyramide. In these conversions, chloride is displaced. Pyrithione, the conjugate base of 2-mercaptopyridine-N-oxide, is a fungicide found in some shampoos. Oxidation 2-chloropyridine gives 2-chloropyridine-N-oxide. The antihistamine pheniramine may be generated via the reaction of phenylacetonitrile with 2-chloropyridine in the presence of a base.


2-Chloropyridine, Environmental properties
Although pyridine is an excellent source of carbon, nitrogen, and energy for certain microorganisms, introduction of a halogen moiety significantly retards degradation of the pyridine ring. With the exception of 4-chloropyridine, each of the mono- and di-substituted chloropyridines were found to be relatively resistant to microbiological degradation in soil or liquid media. Estimated time for complete degradation was > 30 days. 2-Chloropyridine exhibits extensive volatilization losses from water, less so when present in soil.


2-Chloroquinoline
2-Chloroquinoline is an organic compound with the formula ClC9H6N. It is one of several isomeric chloro derivatives of the bicyclic heterocycle called quinoline. A white solid, 2-chloroquinoline can be prepared from vinylaniline and phosgene. It is a precursor to 2,2'-biquinoline.


2-Chlorostyrene
2-Chlorostyrene is a chlorinated derivative of styrene with the chemical formula C8H7Cl.


2-Coumarate reductase
In enzymology, a 2-coumarate reductase  or melilotate dehydrogenase (EC ) is an enzyme that catalyzes the chemical reaction


2-Coumarate reductase
Thus, the two substrates of this enzyme are 3-(2-hydroxyphenyl)propanoate and NAD+, whereas its 3 products are 2-coumarate, NADH, and H+.


2-Coumarate reductase
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-CH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 3-(2-hydroxyphenyl)propanoate:NAD+ oxidoreductase. This enzyme participates in phenylalanine metabolism.


2-Cyanoguanidine
2-Cyanoguanidine is a nitrile derived from guanidine. It is a dimer of cyanamide, from which it can be prepared. 2-Cyanoguanidine is a colourless solid that is soluble in water, acetone, and alcohol, but not nonpolar organic solvents.


2-Cyanoguanidine, Production and use
2-Cyanoguanidine is produced by treating cyanamide with base. It is produced in soil by decomposition of cyanamide. A variety of useful compounds are produced from 2-cyanoguanidine, guanidines and melamine. For example, acetoguanamine and benzoguanamine are prepared by condensation of cyanoguanidine with the nitrile:


2-Cyanoguanidine, Production and use
Cyanoguanidine is also used as a slow fertilizer. Formerly, it was used as a fuel in some explosives. It is used in the adhesive industry as a curing agent for epoxy resins.


2-Cyanoguanidine, Chemistry
Two tautomeric forms exist, differing in the protonation and bonding of the nitrogen to which the nitrile group is attached.


2-Cyanoguanidine, Chemistry
2-Cyanoguanidine can also exist in a zwitterionic form via a formal acid–base reaction among the nitrogens.


2-Cyanoguanidine, Chemistry
Loss of ammonia (NH3) from the zwitterionic form, followed by deprotonation of the remaining central nitrogen atom, gives the dicyanamide anion, [N(CN)2]−.


2-D (character)
Stuart Harold "2-D" Pot is a fictional English singer, musician and member of the British virtual band Gorillaz. He provides the lead vocals and plays the keyboard for the band. 2-D's singing voice is provided by Blur frontman Damon Albarn on Gorillaz' recordings and performances; his speaking voice was provided by actor Nelson De Freitas in various Gorillaz direct-to-video projects such as Phase One: Celebrity Take Down and Phase Two: Slowboat to Hades. In 2017, Kevin Bishop was cast as the new speaking voice of 2-D. He was created by Albarn and Jamie Hewlett in 1998.


2-D (character), Development, Characterization
2-D was loosely based on Chris Gentry from the Britpop band Menswear and a mutual friend of Jamie Hewlett and Damon Albarn named Stuart Lowbridge, who has worked as a stage engineer for Albarn since the early days of his career. Before co-creating Gorillaz, Hewlett originally had the idea of forming a cartoon band called "Sour Grapes" with Gentry and Graham Coxon of Albarn's other band Blur. 2-D has been described by Gorillaz' former drummer and writer Cass Browne as being a "composite of Chris, Damon, and lots of other rock frontmen".


2-D (character), Development, Characterization
2-D was originally created as a representation of the "classic stupid pretty boy singer" stereotype that Hewlett found to be in many bands at the time and was the first character that Hewlett and Albarn created for Gorillaz in 1998, making his first official appearance in Gorillaz' debut EP Tomorrow Comes Today in 2000. He has been described in the Tomorrow Comes Today EP's booklet as being "a sweetheart with a blank sheet of paper where a brain should be".


2-D (character), Development, Characterization
Albarn has stated that Gorillaz' sixth studio album The Now Now is "in the world of 2-D" and has often stated the influence that the album's backstory in the fictional universe of Gorillaz had on the making of the album and its songwriting process, mentioning that the idea behind the album was to make an album of songs from 2-D's perspective.


2-D (character), Development, Voice
While 2-D's singing voice is provided by Gorillaz co-creator Damon Albarn, his speaking voice is provided by actor and comedian Kevin Bishop. Albarn has claimed that 2-D's singing voice was developed from a vocal effect produced by equipment in his studio that he has said is "not Auto-Tune, but it was an early form of synthetic voice". Gorillaz engineer Stephen Sedgewick says of the effect, "The main lo-fi telephone-like effect is the typical 2-D sound...I can't tell you what it is, but it's done with hardware.


2-D (character), Development, Voice
The plug-ins on the inserts are a Waves Renaissance De-esser and RVox, and the Waves Kramer PIE [compressor], which I use a lot on vocals." 2-D's main musical characteristic has been described by Albarn as being abstract and esoteric dystopian lyrics that are often recited through spoken word Sprechgesang. In contrast to his singing voice, 2-D's speaking voice is high-pitched and squeaky, and at one point he had a speech impediment and a strong lisp due to his missing teeth.


2-D (character), Development, Voice
Although he is from the West Sussex region of England, 2-D speaks in a mockney accent rather than a Sussex dialect. In his first spoken appearances on the press release interview CD "The Apex Tapes", 2-D's speaking voice was originally portrayed as being lower and softer than the high-pitched, wheezy speaking voice that the character would later develop.


2-D (character), Development, Voice
In Gorillaz' first American press interview (an interview with Rolling Stone), Albarn and Hewlett attempted to provide the speaking voices of 2-D and bandmate Murdoc Niccals, as they had not yet chosen proper voice actors for the characters, but Albarn gave up and the act was dropped after three questions. After this, Nelson De Freitas was chosen as the speaking voice of 2-D. In 2017, De Freitas was replaced by actor and comedian Kevin Bishop, who was suggested by Harry Enfield after declining an offer to voice the character.


2-D (character), Fictional history
Stuart Pot was born on 23 May 1978 to David and Rachel Pot. The original surname of Stuart's father was "Tusspot", but he legally changed it to "Pot", shortly before Stuart was born.


2-D (character), Fictional history
His father, David, works as a mechanic and as a fairgrounds worker, while his mother, Rachel, works as a nurse. He was born in Crawley, West Sussex, England and attended St Wilfrid's Catholic School. When he was 11 years old, Stuart was involved in an accident where he fell from a tree and hit his head. This caused all his natural brown hair to shed, until it eventually grew back in a deep azure blue color. The accident also caused him to experience frequent migraines, for which his mother supplied him with painkillers.


2-D (character), Fictional history
At age 19, Stuart was hit in the face by Murdoc Niccals when he crashed his Vauxhall Astra into Uncle Norm's Organ Emporium in an attempt to raid the store of its musical equipment. This caused Stuart to receive hyphema in his left eye and put him into a coma. Murdoc was then arrested and sentenced to 30,000 hours of community service, as well as to care for the vegetablized Stuart for ten hours a week. Not long after, Murdoc injured Stuart again while pulling off 360 donuts to impress a small crowd of women.


2-D (character), Fictional history
Stuart came crashing through the windshield of the car and fractured his other eye. After the incident, he woke up from his vegetative state and was given the nickname "2-D", which refers to the two dents in his head. He was then recruited by Murdoc and chosen to be the lead vocalist of a new band he was forming after his last band had broken up. Gorillaz call the day 2-D and Murdoc first crossed paths "D-Day".


2-D (character), Fictional history
In 1998, 2-D began dating a woman named Paula Cracker, who would eventually also join 2-D as a member of Gorillaz and begin to take on the role of the lead guitarist after he and Murdoc moved into Kong Studios. Paula would quickly be removed from the band's lineup after being caught having a sexual affair with Murdoc in the Kong Studios bathroom and she would then eventually be replaced on guitar by a child prodigy named Noodle, with the band ready to launch and playing their very first gig in 1998 soon after.


2-D (character), Fictional history
Following the release and worldwide success of Gorillaz, 2-D and his bandmates would soon move to Los Angeles, California after being approached by a famous Hollywood director who was interested in making a Gorillaz movie. In a meeting between the band members regarding potential concepts for a Gorillaz film, 2-D was choked out by Murdoc, who would then be punched in the face by Russel Hobbs in his defense. Gorillaz split up immediately after this event.


2-D (character), Fictional history
After 2-D relocated back to England, he worked at his father's amusement park in Eastbourne and made friends with former Boyzone member Shane Lynch and Brian Setzer of Stray Cats. After Gorillaz had been off 2-D's mind for quite some time, he returned to Kong Studios after receiving a text from Noodle that informed him that she had started work on demos for a new Gorillaz album and needed him on vocals.


2-D (character), Fictional history
The release of Demon Days' proved to be a worldwide success and further catapulted Gorillaz' popularity, Noodle was then presumed dead in the aftermath of the music video for "El Mañana", which would cause 2-D and Russel to spiral into a panic and depart from the band yet again. 2-D would eventually move on from Gorillaz and relocate to an apartment in Beirut, where Murdoc would later track him down and kidnap him against his will to bring to his newly built island to rejoin Gorillaz for the band's third album, Plastic Beach.


2-D (character), Fictional history
During Gorillaz' 2010 Escape to Plastic Beach World Tour, 2-D made a Gorillaz album himself called The Fall. After the tour, Plastic Beach was shot down by pirates and the band would again part ways. In Gorillaz' 2016 interactive short story "The Book of 2-D", it was revealed that 2-D hid underwater following the pirate attack on Plastic Beach and was eventually swallowed alive by a whale who would later die and be washed ashore, freeing 2-D soon afterwards in an island with no food except for the whale's blubber and the island's sand.


2-D (character), Fictional history
After being stranded for months, 2-D sighted a plane flying above him. Moved to tears by this revelation, he set off on its direction, hoping to find a sign of civilization. After following the planes direction for 23 minutes, he soon realized he was actually in the middle of a beach rave on the island of Guadalupe off the west coast of Mexico.


2-D (character), Fictional history
2-D was soon flown back to Heathrow Airport in the United Kingdom, and upon arrival, a man offered him a ride to West London, where he would reunite with Murdoc at Studio 13 and later be joined by Russel and Noodle to begin recording Humanz, Gorillaz' first studio album since 2010.


2-D (character), Fictional history
After the success of Humanz, Murdoc was revealed to be incarcerated at Wormwood Scrubs prison in an acceptance speech from the band during the 2018 Brit Awards. It would also be revealed soon afterwards that Gorillaz had made an album called The Now Now without contributions from Murdoc, who was replaced by Ace from Cartoon Network's animated series The Powerpuff Girls while he was in prison. 2-D became the temporary leader of Gorillaz during the making of The Now Now and was in charge of the musical direction of the band for the album. Murdoc's incarceration led 2-D to gain a significant boost in self-esteem, to the point of appearing to be rude and developing an increasingly overinflated ego. Immediately after Murdoc's return, 2-D appears to have returned to his usual self.


2-D (character), Fictional history
On 24 September 2019, Gorillaz revealed through social media that 2-D had again been on vacation in Beirut and sent a postcard to his bandmates in which he makes a reference to parts he gathered for a machine that would later be revealed to be the Song Machine, the latest audiovisual project from Gorillaz.


2-D (character), Fictional history
In season one of Song Machine, 2-D is oblivious to the various attempts made by Murdoc to distract him as he tries to gain access to portals in the newly relocated Kong Studios after he and the rest of the band leave him behind as they use it for a trip. 2-D is the host of all of the interviews in Song Machine's accompanying "Machine Bitez".


2-D (character), Personality
2-D was created by Jamie Hewlett to represent the "stupid pretty boy singer" he identified as a part of many manufactured bands at the time. As such, 2-D is lacking significantly in intelligence and critical thinking skills as a result of various head injuries and brain damage that he's experienced throughout his life. Because of this, he can also come across as being very awkward at times. He has been described by his ex-girlfriend Paula Cracker in Rise of the Ogre as being "very sweet...[but] a bit thick though".


2-D (character), Personality
He is often ridiculed by bandmate Murdoc for his perceived stupidity and ignorance. He was oblivious to Murdoc's frequent abuse and admired him regardless, looking up to him as a big brother figure and displaying symptoms of acute stockholm syndrome. His bandmate Russel has once stated that 2-D is "kind of like a pet. Obedient, eager to please. Eats a lot of dog food". 2-D is also absent-minded and daydreams frequently, often spacing out for no apparent reason. He is clumsy and accident-prone, having received many injuries throughout his life.


2-D (character), Personality
He is generally calm and peaceful, rarely expressing anger or frustration towards others. 2-D is polite and well-mannered, with his kindness often working to his detriment, since he hardly ever stands up for himself when antagonized. He is very quiet and shy and has also shown himself to be timid and easily frightened, being very jumpy at times.


2-D (character), Personality
Despite his apparent lack of intelligence, 2-D has also occasionally exhibited some semblance of cognitive ability, with his musicianship and creativity being the most significant example. He has also shown an interest in computers and technology in the past, once collecting a large amount of 80s computer parts. It was also once insinuated that he went to law school and attempted to complete a law degree at University of Oxford. He is also said to have had good grades in school as a student.


2-D (character), Personality
He has also shown an extent of knowledge in cultures he is passionate about, especially music of all genres, and horror movies. He has also sometimes offered thoughtful answers to interview questions, but moments like this are generally rare and his dialogue usually displays a lack of cognitive skills. His hyphema has resulted in a vision impairment which further affected his clumsiness. He has been a Buddhist since discovering the Tibetan independence movement and shares a zen-bond with bandmate Noodle.


2-D (character), Personality
2-D has also been shown to have an addictive personality, with the foremost example being becoming addicted to painkillers as a side effect of his mother's treatments for his head injuries. 2-D also smokes frequently and is commonly shown smoking a cigarette in artwork, like his bandmate Murdoc. In the Song Machine episode "Pac-Man", 2-D becomes addicted to a Pac-Man arcade machine built for him by Murdoc.


2-D (character), Personality
2-D has had many romantic and sexual partners in his life, at one point claiming to have dated six other women after breaking up with Paula Cracker, including Rachel Stevens of the pop group S Club 7. He has once claimed to be a vegetarian and is allergic to several foods, hence his slim body type. He has also once said that he frequently suffers from panic attacks and struggles with insomnia. He has also been shown to be snarky and sarcastic at times.


2-D (character), Personality
In the Plastic Beach era of Gorillaz, 2-D spiraled into a depression and in contrast to his usual self, became fed up with Murdoc and began to resent him and stand up to him, although the two have since made up. In the backstory for The Now Now, 2-D quickly began to appear rude and cocky in his interactions with others without bandmate Murdoc around, although this aspect of his personality has been toned down since Murdoc's return.


2-D (character), Physical appearance
2-D's physique is tall and skinny; his hands and feet are large and he has long limbs, with his height standing at 6'2". The character has pale skin and spiky azure blue hair. Thereafter, he is also depicted with a notable lack of visible pupils in his eyes due to the blood leakage from his hyphema; while his eyes can range from black to white, they predominately remained black throughout the first four phases. However, since The Now Now, 2-D's eyes have been almost exclusively white.


2-D (character), Physical appearance
Additionally, he is also shown to be missing a few front teeth, and has sometimes been shown wearing a golden tooth. As with the rest of the Gorillaz characters, 2-D has thick, bushy, rectangular eyebrows.


2-D (character), Physical appearance
In Gorillaz artwork, 2-D's hair was darker and the spikes on his hair were thicker and sharper than they would become in much of the artwork for Demon Days and Plastic Beach, where his hair became messier and brighter and the spikes became thinner and looser, to the point where he now appears to have a mildly receding hairline in some artwork for Humanz and The Now Now. He also has blue bags under his eyes. He has a pointy chin and head shape that looks similar to that of fellow band member Noodle.


2-D (character), Physical appearance, Styles
Although primarily presented through 2D animation, 2-D and the rest of Gorillaz sometimes appear in the form of 3D animation, such as in the music videos for "Stylo", "Strobelite", and "Sleeping Powder", as well as several live visuals, such as the visual for their performance of "Dirty Harry" at the 2006 Brit Awards and in interludes and promotional content for the 2010 Escape to Plastic Beach Tour. The motion capture 3D models of 2-D from the Humanz album campaign typically show him wearing the same outfit he wore in the music video for "Saturnz Barz".


2-D (character), Physical appearance, Styles
On the Humanz album cover, 2-D appears in the form of a photorealistic 3D model along with the rest of the characters. He appears as an 8-bit character in the visualizer for "Garage Palace", and for the 8-bit icons of the characters that appear in the Humanz Tour, The Now Now Tour, and the Gorillaz documentary Reject False Icons. The music video for "Tranz" occasionally portrays 2-D in the form of both a 3D model and stop motion claymation in certain sections of the video. 2-D and Murdoc appeared together as puppets made by The Jim Henson Company at Jim Henson's Creature Shop in Gorillaz' 2006 performance at the Apollo Theater in Harlem and for their appearance at the 2006 Webby Awards, played by The Muppets puppeteers Matt Vogel and Joey Mazzarino respectively.


2-D (character), Physical appearance, Age
2-D and the other Gorillaz characters have been illustrated as aging progressively with each new Gorillaz release. 2-D was originally in his early 20s when Gorillaz was released, but has since gotten older and is in his early 40s as of 2018. Since Humanz, 2-D has gained wrinkles and a receding hairline. He has also developed more defined wrinkles on his hands. His nose has also changed shape since Humanz, appearing to be somewhat more pointed than it was before. Although he has aged somewhat over time, as the "pretty boy singer" of the group, 2-D generally has a youthful appearance with clear skin and little to no facial hair and few blemishes or wrinkles, even maintaining this look into his 40s.


2-D (character), Physical appearance, Fashion
Along with the other Gorillaz members, 2-D's wardrobe changes very frequently and he is rarely depicted wearing the same clothing twice. This was a conscious decision from Jamie Hewlett to make the characters feel more realistic and stand apart from most other cartoon characters, who rarely if ever change their clothes. His wardrobe typically consists of a wide range of T-shirts and skinny jeans with Converse Chuck Taylor All-Stars, although he is often depicted in a long-sleeved shirt, sweatshirt, or jacket and boots as well.


2-D (character), Physical appearance, Fashion
In the Gorillaz era of the band, 2-D's T-shirts were typically graphic tees that featured a distinct printed graphic, an element that became less prominent starting in the Demon Days album campaign, where he typically wore plain short-sleeved T-shirts over long sleeved shirts. In the Plastic Beach era of the band, 2-D typically wore sleeveless shirts or a short-sleeved T-shirt and grey pants with a pair of boots, and he often wore a bandana and a clown mask or sea captain hat. In the Humanz era of Gorillaz, 2-D was most frequently depicted in wardrobe inspired by the Black Panther Party and the Sandinista National Liberation Front and The Now Now's artwork mostly showed 2-D in various sweatshirts and leather jackets.


2-D (character), Role in Gorillaz
As the frontman of Gorillaz, 2-D's main roles in the band entail serving as both the lead vocalist and keyboardist. While he can play other instruments (as can the other Gorillaz members), he generally focuses on his role as vocalist and keyboardist for most of the band's discography. Exceptions to this include the 2018 Gorillaz album The Now Now, where 2-D is often depicted playing guitar, and 2010's The Fall, which 2-D created largely by himself. In most cases, 2-D's singing voice sounds significantly different than his normal speaking voice.


2-D (character), Role in Gorillaz
His vocal range is very wide, and he has sung everything from baritone to falsetto. Gorillaz co-creator Damon Albarn provides all of 2-D's singing voice in their music, including songs where he provides spoken-word and rapped verses. 2-D apparently has had some influence in the lyric-writing process (as evidenced by the credits on the insert of the titular debut album) even though his intelligence is reputedly negligible. Apparently, Murdoc has been said to have had Albarn occasionally help teach 2-D to sing better than he already could, and apparently even sing in some of their songs, as stated in an NME interview with Albarn.


2-D (character), Role in Gorillaz
While Murdoc is usually portrayed as the main director behind most Gorillaz albums (or so he claims), 2-D is depicted as the member behind Gorillaz albums such as 2010's The Fall and 2018's The Now Now. 2-D also wrote and recorded Gorillaz' 2017 single "Sleeping Powder" by himself, with the music video for the song featuring him exclusively.


2-D (character), Other appearances, Music
In 2003, 2-D was credited as a guest artist on the songs "Small Time Shot Away" by Massive Attack, and FM by Nathan Haines. He contributed additional guitar on several tracks on Spacemonkeyz' 2003 Gorillaz remix album Laika Come Home, as well as an additional stylophone solo on the "Slow Country" remix "Strictly Rubbadub". He also recorded vocals for the album's "M1 A1" remix "Lil' Dub Chefin'". It has been claimed by Murdoc in the "Gorillaz Are Ten" Spotify radio show that the original demo version of the Gorillaz song "Dirty Harry" called "I Need A Gun" from Damon Albarn's 2003 solo EP Democrazy is a duet between 2-D and Albarn.


2-D (character), Other appearances, Visual
In 2001, 2-D became a spokesperson of the Free Tibet campaign after Gorillaz were asked by Adam Yauch of Beastie Boys to work with the organization, appearing in a short commercial for the campaign the same year. On 15 June 2012, an illustration of 2-D was designed by Jamie Hewlett in promotion of the Dalai Lama's visit to the United Kingdom. In 2017, 2-D appeared in an official advertisement campaign for the English professional football team Chelsea F.C. to launch their Chelsea F.C. Nike football kit with Chelsea player David Luiz.


2-D (character), Other appearances, Visual
2-D and the rest of Gorillaz appear on the back cover of Hewlett's 2017 art book, featured alongside characters from all of Hewlett's projects. On 23 October 2020, 2-D and Beck appeared on an episode of the online virtual talk show Animal Talking with Gary Whitta with Albarn and Hewlett as special guests as Animal Crossing avatars, in promotion of the Song Machine episode "The Valley of the Pagans".


2-D (character), Other appearances, Visual
2-D and Murdoc appear as the puppet versions of themselves from Demon Days Live in the 2006 Webby Awards to accept their "Artist of the Year" award. On 23 July 2020, 2-D appeared in a virtual Comic-Con panel for a short interview about Gorillaz Almanac. He performed a live duet with Albarn of the Song Machine song "Aries" for an episode of Jimmy Kimmel Live! on 20 May 2020.


2-D Blacktop
"2-D Blacktop" is the fifteenth episode of the seventh season of the animated sitcom Futurama. It originally aired on Comedy Central on June 19, 2013. The episode was written by Michael Rowe and directed by Raymie Muzquiz. Professor Farnsworth joins a gang of street racing punks, and ends up in a two-dimensional world. The title is likely a reference to the movie Two-Lane Blacktop.


2-D Blacktop, Plot
While the crew prepare to depart for a delivery, Leela argues with Farnsworth over the new modifications he has made to Bessie. He dismisses her concerns, and the ship barely clears the hangar before crashing. Sal tows Bessie away and Farnsworth breaks into the scrapyard and declares that he will convert the ship into a hot-rod using the spare parts lying around the scrapyard.


2-D Blacktop, Plot
The next morning, Farnsworth flies away from the scrapyard in Bessie, now a nearly unrecognizable junk heap. Two muscle-hovercars move up on either side of him and Farnsworth challenges them to a race, which they accept. A brief race ensues, in which the police give chase. Farnsworth escapes the police by using a dimensional drift device he had installed the night before.


2-D Blacktop, Plot
At headquarters, Leela unveils the new ship, a nearly featureless gray box that promises to be both safe and boring. Hermes sends Leela to shop for groceries and deliver Fry and Bender to karate class. During her return from these errands to headquarters, Farnsworth pulls alongside her in his hot-rod and tells her that she is not cool. Leela exclaims that she can still outdrive him, even in her ultra-safe ship. As they race on a looped track, Farnsworth again uses his dimensional drift device, but accidentally collides with Leela's ship. Fry is standing between the two ships as they collide, compressing him and the ships to near-flatness in a neat disc shape.


2-D Blacktop, Plot
The spectators presume Fry, Leela, and Farnsworth to be dead. A two-dimensional, but otherwise healthy, Farnsworth conjectures that colliding at relativistic speed has collapsed the group into two dimensions. Bender arrives on the scene, explaining that he had been napping onboard Leela's ship.


2-D Blacktop, Plot
Two creatures calling themselves the Lords of Flatbush arrive and report that a feast is being held in honor of Farnsworth and the others. At the feast, when Farnsworth attempts to explain three-dimensionality to the King of Flatbush, the King becomes angry and orders Farnsworth to be executed. Farnsworth and the others flee. Arriving at the two ships, Leela suggests that they use the dimensional drift device to attempt a return to the 3-D world. Just as Sal and the others in the 3-D world begin to cremate the remains, the remains themselves become the normal Bessie and her normal passengers. All is well, and Hermes indicates that the entire incident lasted about five minutes.


2-D Blacktop, Reception
The A.V. Club gave this episode a B+. Max Nicholson of IGN gave the episode a 7.3/10 "Good" rating, saying the episode had a "unique and promising idea that was long-delayed in favor of safe but pleasant fare."


2-Decenal
2-Decenal (dec-2-enal) is an organic compound with the chemical formula of C10H18O. It exists as a pair of cis and trans isomers, (2E)-2-decenal and (2Z)-2-decenal. It is an oily, clear liquid under normal conditions, that may be yellow due to impurities. 2-Decenal is described as having a strong, waxy odor. It is found in animal food (in trace quantities), and is part of the essential oil of coriander. 2-Decenal is also used as a flavoring agent.


2-Decenal, Occurrence
2-Decenal is found in a wide variety of foods. It has been reported in bitter orange peel, blackberry, ginger, butter, mushroom, kiwi, bacon fat, roast beef, beef fat, heated beef fat, bilberries, carrot root, boiled chicken, chicken broth, cranberry press residue, ham, lingonberry, orange, heated pork fat, potato chip, soy bean, boiled mutton, tea, roasted hazelnuts, french fries, tomato, wheat bread,  roasted pecans, rice, roasted peanuts, and coriander leaf. Alongside (E)-2-dodecenal, the presence of this aldehyde in coriander leaf has been linked to a commonly reported distaste for the herb among people with a certain variant of the OR6A2 gene.


2-Decenal, Applications
2-Decenal can be used as a nematicide (a pesticide used to kill plant-parasitic nematodes). It is a mutagen, but it also has a biological role as a pheromone, which is released by an organism when damaged by a predator which warns other individuals that there is a danger.


2-Decenal, Synthesis
2-Decenal can be synthesized by reacting octanal with ethyl vinyl ether, and subsequently hydrolyzing the mixture.


2-Dehydro-3-deoxy-phosphogluconate aldolase
In enzymology, a 2-dehydro-3-deoxy-phosphogluconate aldolase (EC ), commonly known as KDPG aldolase, is an enzyme that catalyzes the chemical reaction


2-Dehydro-3-deoxy-phosphogluconate aldolase
Hence, this enzyme primarily has one substrate, 2-dehydro-3-deoxy-D-gluconate 6-phosphate, and two products, pyruvate and D-glyceraldehyde 3-phosphate.


2-Dehydro-3-deoxy-phosphogluconate aldolase
This enzyme belongs to the family of lyases, specifically the aldehyde-lyases, which cleave carbon-carbon bonds. It is used in the Entner–Doudoroff pathway in prokaryotes, feeding into glycolysis. 2-dehydro-3-deoxy-phosphogluconate aldolase is one of the two enzymes distinguishing this pathway from the more commonly known Embden–Meyerhof–Parnas pathway. This enzyme also participates in following 3 metabolic pathways: pentose phosphate pathway, pentose and glucuronate interconversions, and arginine and proline metabolism.


2-Dehydro-3-deoxy-phosphogluconate aldolase
In addition to the cleavage of 2-dehydro-3-deoxy-D-gluconate 6-phosphate, it is also found to naturally catalyze Schiff base formation between a lysine E-amino acid group and carbonyl compounds, decarboxylation of oxaloacetate, and exchange of solvent protons with the methyl hydrogen atoms of pyruvate.


2-Dehydro-3-deoxy-phosphogluconate aldolase, Nomenclature
The systematic name of this enzyme class is 2-dehydro-3-deoxy-D-gluconate-6-phosphate D-glyceraldehyde-3-phosphate-lyase (pyruvate-forming). Other names in common use include:


2-Dehydro-3-deoxy-phosphogluconate aldolase, Enzyme structure
KDPG Aldolase was recently determined to be a trimer through crystallographic three-fold symmetry, with 225 residues. The enzyme was determined to have a  molecular weight of 23,942. The trimer is stabilized primarily through hydrophobic interactions. The molecule has tertiary folding similar to triosephosphate isomerase and the A-domain of pyruvate kinase, forming an eight strand α/β-barrel structure. The α/β-barrel structure is capped on one side by  the N-terminal helix. The other side, the carboxylic side, contains the active site. Each subunit contains a phosphate-ion bound in position of the aldolase biding site. It has been found that there are four cysteinyl groups present in each subunit, with two readily accessible and two buried in the subunit.


2-Dehydro-3-deoxy-phosphogluconate aldolase, Enzyme structure
The active site contains the zwitterionic pair Glu-45/Lys-133. The Lysine, which is involved in the formation of the Schiff base is coordinated by a phosphate ion and two solvent water molecules. The first water molecule serves as a shuttle between the Glutamate and the substrate, staying bound to the enzyme throughout the catalytic cycle. The second water molecule is a product of the dehydration of the carbinolamine that leads to the formation of the Schiff base. It also functions as the nucleophile during hydrolysis of the enzyme-product Schiff base, leading to the release of pyruvate.


2-Dehydro-3-deoxy-phosphogluconate aldolase, Enzyme structure
As of late 2007, 13 structures have been solved for this class of enzymes, with PDB accession codes , , , , , , , , , , , , and .


2-Dehydro-3-deoxy-phosphogluconate aldolase, Enzyme mechanism
One of the reactions KDPG Aldolase catalyzes, as in the Entner–Doudoroff pathway, is the reversible cleavage of 2-keto-3-deoxy-6-phosphogluconate (KDPG) into pyruvate and D-glyceraldehyde-3-phosphate. This occurs through a stereospecific retro-aldol cleavage. A proton transfer between the zwitterionic pair Glu-45/Lys-133 in the active site activates Lysine to serve as the nucleophile in the first step and Glutamate to aid in the base catalysis involved in the carbon-carbon cleavage. Lysine Residue 133 serves as the nucleophile and attacks the carbonyl group of 2-Keto-3-deoxy-6-phosphogluconate to form a protonated carbinolamine intermediate, also known as a Schiff base intermediate.


2-Dehydro-3-deoxy-phosphogluconate aldolase, Enzyme mechanism
The intermediate is stabilized by hydrogen bonding with residues in the active site. A three carbon residue, glyceraldehyde 3-phosphate, is cleaved off through base catalysis with a water molecule and residue Glu-45. The pyruvate is generated through the nucleophilic attack of water on the Schiff-base to reform a ketone. Aromatic interaction with Phe-135 ensures the stereospecific addition involved in the reverse process.


2-Dehydro-3-deoxy-phosphogluconate aldolase, Enzyme mechanism
KDPG aldolase has also been shown to catalyze the exchange of hydrogen atoms of the methyl groups of pyruvate with protons of the solvent.


2-Dehydro-3-deoxy-phosphogluconate aldolase, Evolutionary significance, History
Arguments have been made for both the convergent and divergent evolution of α/β-barrel structured enzymes such as KDPG Aldolase, triosephosphate isomerase, and the A-domain of pyruvate kinase.


2-Dehydro-3-deoxy-phosphogluconate aldolase, Evolutionary significance, History
Convergent evolution can lead to geometrically similar active sites while each enzyme has a distinct backbone conformation. Convergence to a common backbone structure, as is the case here however, has not been observed, although it is argues that it might be possible for a symmetrically repetitive structure as the one observed here. The similarity in the folding of the three enzymes and the exceptional symmetry commonly suggests divergent evolution from a common ancestor. The functional similarity of the enzymes remains the strongest argument for divergent evolution. All three enzymes activate a C–H bond adjacent to a carbonyl group. The active sites are located at the carboxylic ends of the β strands. Such congruence is in favor of divergent evolution.


2-Dehydro-3-deoxy-phosphogluconate aldolase, Evolutionary significance, History
Should the divergent evolution hypothesis prevail, this would suggest the existence of a class of enzymes with unrelated amino acid sequences yet analogous symmetrical structure and folding.


2-Dehydro-3-deoxy-phosphogluconate aldolase, Evolutionary significance, History
KDPG aldolase has limited utility due to its high specificity for its natural substrates in the cleavage of KDPG and the reverse addition of D-glyceraldehyde-3-phosphate and pyruvate. In vitro evolution has allowed KDPG aldolase to be converted into a more efficient aldolase with altered substrate specificity and stereoselectivity thereby improving its utility in asymmetric synthesis. Rather than modifying the recognition site, the substrate is modified by moving the active site lysine from one  β strand to a neighboring one. The evolved aldolase is capable of accepting both D- and L-glyceraldehyde in their non-phosphorylated form.


2-Deoxy-D-glucose
2-Deoxy-d-glucose is a glucose molecule which has the 2-hydroxyl group replaced by hydrogen, so that it cannot undergo further glycolysis. As such; it acts to competitively inhibit the production of glucose-6-phosphate from glucose at the phosphoglucoisomerase level (step 2 of glycolysis). 2-Deoxyglucose labeled with tritium or carbon-14 has been a popular ligand for laboratory research in animal models, where distribution is assessed by tissue-slicing followed by autoradiography, sometimes in tandem with either conventional or electron microscopy.


2-Deoxy-D-glucose
2-DG is up taken by the glucose transporters of the cell. Therefore, cells with higher glucose uptake, for example tumor cells, have also a higher uptake of 2-DG. Since 2-DG hampers cell growth, its use as a tumor therapeutic has been suggested, and in fact, 2-DG is in clinical trials. It is not completely clear how 2-DG inhibits cell growth. The fact that glycolysis is inhibited by 2-DG, seems not to be sufficient to explain why 2-DG treated cells stop growing. Because of its structural similarity to mannose, 2DG has the potential to inhibit N-glycosylation in mammalian cells and other systems, and as such induces ER stress and the Unfolded Protein Response (UPR) pathway.


2-Deoxy-D-glucose, Use in optical imaging
2-DG has been used as a targeted optical imaging agent for fluorescent in vivo imaging. In clinical medical imaging (PET scanning), fluorodeoxyglucose is used, where one of the 2-hydrogens of 2-deoxy-D-glucose is replaced with the positron-emitting isotope fluorine-18, which emits paired gamma rays, allowing distribution of the tracer to be imaged by external gamma camera(s). This is increasingly done in tandem with a CT function which is part of the same PET/CT machine, to allow better localization of small-volume tissue glucose-uptake differences.


2-Deoxy-D-glucose, Indian adoption for COVID-19 treatment
On May 8, 2021, the Drugs Controller General of India approved an oral formulation of 2-deoxy-D-glucose for emergency use as adjunct therapy in moderate to severe coronavirus patients. The drug was developed by the DRDO along with Dr. Reddy's Laboratories, who jointly claimed via a press release, that the drug "helps in faster recovery of hospitalised patients and reduces supplemental oxygen dependence". The Wire as well as The Hindu noted that the approval was based on poor evidence; no journal publication (or preprint) concerning efficacy and safety are yet available.


2-Deoxy-scyllo-inosamine dehydrogenase
2-deoxy-scyllo-inosamine dehydrogenase (EC , neoA (gene name), kanK (gene name)) is an enzyme with systematic name 2-deoxy-scyllo-inosamine:NAD(P)+ 1-oxidoreductase. This enzyme catalyses the following chemical reaction


2-Deoxy-scyllo-inosamine dehydrogenase (SAM-dependent)
2-deoxy-scyllo-inosamine dehydrogenase (SAM-dependent) (EC , btrN (gene)) is an enzyme with systematic name 2-deoxy-scyllo-inosamine:S-adenosyl-L-methionine 1-oxidoreductase. This enzyme catalyses the following chemical reaction


2-Deoxy-scyllo-inosamine dehydrogenase (SAM-dependent)
This enzyme participates in the biosynthetic pathway of the aminoglycoside antibiotics of the butirosin family.


2-Deoxystreptamine N-acetyl-D-glucosaminyltransferase
2-deoxystreptamine N-acetyl-D-glucosaminyltransferase (EC , btrM (gene), neoD (gene), kanF (gene)) is an enzyme with systematic name UDP-N-acetyl-alpha-D-glucosamine:2-deoxystreptamine N-acetyl-D-glucosaminyltransferase. This enzyme catalyses the following chemical reaction


2-Deoxystreptamine N-acetyl-D-glucosaminyltransferase
Involved in the biosynthetic pathways of several clinically important aminocyclitol antibiotics.


2-Deoxystreptamine glucosyltransferase
2-deoxystreptamine glucosyltransferase (EC , kanF (gene)) is an enzyme with systematic name UDP-alpha-D-glucose:2-deoxystreptamine 6-alpha-D-glucosyltransferase. This enzyme catalyses the following chemical reaction


2-Deoxystreptamine glucosyltransferase
This enzyme is involved in the biosynthesis of kanamycin B and kanamycin C.


2-Dimethylaminoethylazide
2-Dimethylaminoethylazide (DMAZ) is a liquid fuel being investigated for use as a spacecraft propellent to replace the toxic, carcinogenic monomethylhydrazine. It is a member of the competitive impulse non-carcinogenic hypergol (CINCH) family which were assessed as a replacement for hydrazine-derived propellants. DMAZ was also found to be sensitive to impact, direct flame, shock wave, heat in confined space, and electrostatic discharge.


2-Dimethylaminoethylazide, Ignition delays
During their inquiry into finding alternative hypergolic fuel, a joint effort by the Aviation and Missile Research, Development, and Engineering Center (AMRDEC), the U.S. Army Research Laboratory (ARL), and the National Aeronautics and Space Administration (NASA) determined that DMAZ could perform competitively with Aerozine-50 and is less toxic than hydrazine-based fuels. However, DMAZ-inhibited red fuming nitric acid (IRFNA) systems have demonstrated longer ignition delays than monomethylhydrazine-IRFNA systems. In an effort to address this issue, researchers synthesized the related compounds 2-azidoethanamines—2-azido-N-methylethanamine (MMAZ) and 2-azido-N-cyclopropylethanamine (CPAZ) in hopes of enhancing the reactivity of DMAZ's amine nitrogen to reduce ignition delays. MMAZ is not hypergolic, while CPAZ is hypergolic.


2-Dimethylaminoethylazide, Ignition delays
According to research conducted by Army Research Laboratory, the azido group in DMAZ's lowest energy structure will prevent the transfer of protons from nitric acid to the amine lone pair acid, a chemical reaction that may be associated with a rate-limiting step in DMAZ-IRFNA ignition.


2-Dimethylaminoethylazide, Ignition delays
However, according to a 2014 ARL report, a correlation between compound basicities and ignition delays was not observed, which indicates that the proton transfer from nitric acid to DMAZ's amine may not be a rate-controlling step in the ignition process of DMAZ-IRFNA systems.


2-Diphenylmethylpyrrolidine
2-Diphenylmethylpyrrolidine (Desoxy-D2PM), also known as 2-benzhydrylpyrrolidine, is a stimulant psychoactive drug. It is the 4-dehydroxylated structural analog of diphenylprolinol (D2PM), and is also similar in structure to desoxypipradrol (2-DPMP), both of which act as norepinephrine-dopamine reuptake inhibitors (NDRIs). Like D2PM and 2-DPMP, Desoxy-D2PM is sold as a designer drug and has been used in the manufacture of legal highs. It has been marketed under the names A3A New Generation, A3A Methano, and Green Powder, and has been reported to cause hallucinations, violent behavior, dilated pupils, tachycardia, and high blood pressure. Literature data suggest that it can produce the same psychotropic effects as other stimulants, but with a longer duration of action.


2-Diphenylmethylpyrrolidine
Desoxy-D2PM has two enantiomers which are used industrially in their purified form as chiral derivatizing agents during chemical synthesis.


2-Diphenylmethylpyrrolidine
As of 4 November 2010, the UK Home Office announced a ban on the importation of 2-diphenylmethylpyrrolidine, following a recommendation from the ACMD. It was due to become a class B drug on 28 March 2012, but the bill was scrapped, due to the presence of two steroids included in the bill that were later recommended to remain uncontrolled.


2-Diphenylmethylpyrrolidine
It was made a class B drug and placed in Schedule I on 13 June 2012.


2-Diphenylphosphinobenzaldehyde
2-Diphenylphosphinobenzaldehyde is a phosphine ligand with the formula (C6H5)2PC6H4CHO. It is a yellow solid that dissolves in common organic solvents. The compound condenses with a variety of amines to give phosphine-imine and phosphine-amine ligands. It was first prepared by the reaction of chlorodiphenylphosphine with the Grignard reagent derived from the protected bromobenzaldehyde followed by deprotection. It can also be derived from (2-lithiophenyl)diphenylphosphine.


2-Diphenylphosphinobenzoic acid
2-Diphenylphosphinobenzoic acid is an organophosphorus compound with the formula (C6H5)2PC6H4CO2H. It is a white solid that dissolves in polar organic solvents. The ligand is a component of catalysts used for the Shell higher olefin process. It is prepared by the reaction of sodium diphenylphosphide with the sodium salt of 2-chlorobenzoic acid.


2-EPT probability density function
In probability theory, a 2-EPT probability density function is a class of probability density functions on the real line. The class contains the density functions of all distributions that have characteristic functions that are strictly proper rational functions (i.e., the degree of the numerator is strictly less than the degree of the denominator).


2-EPT probability density function, Definition
A 2-EPT probability density function is a probability density function on R{\displaystyle \mathbb {R} } with a strictly proper rational characteristic function. On either [0,+∞){\displaystyle [0,+\infty )} or (−∞,0){\displaystyle (-\infty ,0)} these probability density functions are exponential-polynomial-trigonometric (EPT) functions.


2-EPT probability density function, Definition
Any EPT density function on (−∞,0){\displaystyle (-\infty ,0)} can be represented as


2-EPT probability density function, Definition
where e represents a matrix exponential, (AN,AP){\displaystyle ({\textbf {A}}_{N},{\textbf {A}}_{P})} are square matrices, (bN,bP){\displaystyle ({\textbf {b}}_{N},{\textbf {b}}_{P})} are column vectors and (cN,cP){\displaystyle ({\textbf {c}}_{N},{\textbf {c}}_{P})} are row vectors. Similarly the EPT density function on [ 0,−∞){\displaystyle [ 0,-\infty )} is expressed as


2-EPT probability density function, Definition
The parameterization (AN,bN,cN,AP,bP,cP){\displaystyle ({\textbf {A}}_{N},{\textbf {b}}_{N},{\textbf {c}}_{N},{\textbf {A}}_{P},{\textbf {b}}_{P},{\textbf {c}}_{P})}is the minimal realization of the 2-EPT function.


2-EPT probability density function, Definition
The general class of probability measures on R{\displaystyle \mathbb {R} } with (proper) rational characteristic functions are densities corresponding to mixtures of the pointmass at zero ("delta distribution") and 2-EPT densities. Unlike phase-type and matrix geometric distributions, the 2-EPT probability density functions are defined on the whole real line. It has been shown that the class of 2-EPT densities is closed under many operations and using minimal realizations these calculations have been illustrated for the two-sided framework in Sexton and Hanzon. The most involved operation is the convolution of 2-EPT densities using state space techniques.


2-EPT probability density function, Definition
Much of the work centers on the ability to decompose the rational characteristic function into the sum of two rational functions with poles located in either the open left or open right half plane. The variance-gamma distribution density has been shown to be a 2-EPT density under a parameter restriction and the variance gamma process can be implemented to demonstrate the benefits of adopting such an approach for financial modelling purposes.


2-EPT probability density function, Definition
It can be shown using Parseval's theorem and an isometry that approximating the discrete time rational transform is equivalent to approximating the 2-EPT density itself in the L-2 Norm sense. The rational approximation software RARL2 is used to approximate the discrete time rational characteristic function of the density.


2-EPT probability density function, Applications
Examples of applications  include option pricing, computing the Greeks and risk management calculations. Fitting 2-EPT density functions to empirical data has also been considered.


2-EXPTIME
In computational complexity theory, the complexity class 2-EXPTIME (sometimes called 2-EXP) is the set of all decision problems solvable by a deterministic Turing machine in O(22p(n)) time, where p(n) is a polynomial function of n.


2-EXPTIME
2-EXPTIME can also be reformulated as the space class AEXPSPACE, the problems that can be solved by an alternating Turing machine in exponential space. This is one way to see that EXPSPACE ⊆ 2-EXPTIME, since an alternating Turing machine is at least as powerful as a deterministic Turing machine.


2-EXPTIME
2-EXPTIME is one class in a hierarchy of complexity classes with increasingly higher time bounds. The class 3-EXPTIME is defined similarly to 2-EXPTIME but with a triply exponential time bound 222nk{\displaystyle 2^{2^{2^{n^{k}}}}}. This can be generalized to higher and higher time bounds.


2-EXPTIME, 2-EXPTIME-complete problems
Generalizations of many fully observable games are EXPTIME-complete. These games can be viewed as particular instances of a class of transition systems defined in terms of a set of state variables and actions/events that change the values of the state variables, together with the question of whether a winning strategy exists.


2-EXPTIME, 2-EXPTIME-complete problems
A generalization of this class of fully observable problems to partially observable problems lifts the complexity from EXPTIME-complete to 2-EXPTIME-complete.


2-Ethoxybenzoic acid
2-Ethoxybenzoic acid (o-ethoxybenzoic acid, EBA) is an organic compound, a carboxylic acid derived from benzoic acid. 2-Ethoxybenzoic acid is used as a component in some dental cements.


2-Ethoxycarbonyl-1-methylvinyl cyclohexyl methylphosphonate
2-Ethoxycarbonyl-1-methylvinyl cyclohexyl methylphosphonate is an extremely toxic organophosphate nerve agent. It is the cyclohexyl methylphosphonate ester of ethyl acetoacetate. The compound has two isomers, the cis isomer and trans isomer, with the trans isomer being more toxic.


2-Ethoxyethanol
2-Ethoxyethanol, also known by the trademark Cellosolve or ethyl cellosolve, is a solvent used widely in commercial and industrial applications. It is a clear, colorless, nearly odorless liquid that is miscible with water, ethanol, diethyl ether, acetone, and ethyl acetate.


2-Ethoxyethanol
2-Ethoxyethanol is manufactured by the reaction of ethylene oxide with ethanol.


2-Ethoxyethanol
As with other glycol ethers, 2-ethoxyethanol has the useful property of being able to dissolve chemically diverse compounds. It will dissolve oils, resins, grease, waxes, nitrocellulose, and lacquers. This is an ideal property as a multi-purpose cleaner, and, therefore, 2-ethoxyethanol is used in products such as varnish removers and degreasing solutions.


2-Ethoxyethyl acetate
2-Ethoxyethyl acetate is an organic compound with the formula CH3CH2OCH2CH2O2CCH3. It is the ester of ethoxyethanol and acetic acid. A colorless liquid, it is partially soluble in water.


2-Ethoxyethyl acetate, Properties
2-Ethoxyethyl acetate is a liquid at room temperature that is used as a solvent. It can be absorbed through inhalation, ingestion, and dermally and should be avoided. It may form an explosive mixture with air. It is also incompatible with strong acids, strong alkalis and nitrates. It may form unstable peroxides and it can soften many plastics, attack plastics, rubber and coatings.


2-Ethoxyethyl acetate, Uses
2-Ethoxyethyl acetate has been used to dissolve polyester and short oil alkyd resins. It has also been used in coatings, dyes, insecticides, soaps and cosmetics. It is also a solvent for nitro-cellulose and is being used for the same applications as ethyl glycol


2-Ethoxyethyl acetate, Uses
In automobile lacquers it has been used to reduce evaporation and to impart a high gloss.


2-Ethoxyethyl acetate, Metabolism
2-Ethoxyethyl acetate is rapidly metabolized to 2-ethoxyethanol in the blood via hydrolysis. Then, 2-ethoxyethanol is metabolized, mainly by alcohol dehydrogenase, to 2-ethoxyacetaldehyde, which is further metabolized by aldehyde dehydrogenase to 2-ethoxyacetic acid (2-EAA) in the liver. These two compounds are the likely active metabolites, which are thought to be involved in some of the toxic effects. Also in the liver, ethylene glycol is produced. All this reactions belong to the phase I of the biotransformation process. In rats, EAA can be conjugated with glycine or may suffer O-deethylated. After this, it can be metabolized to carbon dioxide. An extra pathway in these animals involves microsomal P450 mixed function oxidases, with deethylation producing acetaldehyde and ethylene glycol.