1,1,2,2-Tetrachloroethane
It was once widely used as a solvent and as an intermediate in the industrial production of trichloroethylene, tetrachloroethylene, and 1,2-dichloroethylene. However, 1,1,2,2-tetrachloroethane is no longer used much in the United States due to concerns about its toxicity.


1,1,2,2-Tetrachloroethane
Chronic inhalation exposure in humans results in jaundice and an enlarged liver, headaches, tremors, dizziness, numbness, and drowsiness. The U.S. Environmental Protection Agency has classified it as a Group C possible human carcinogen.


1,1,2,2-Tetrachloroethane
For occupational exposure limits, the Occupational Safety and Health Administration has set a permissible exposure limit for dermal exposures at 5 ppm over an eight-hour time-weighted average. The National Institute for Occupational Safety and Health has a more protective recommended exposure limit for dermal exposures at 1 ppm over an eight-hour time-weighted average.


1,1,2-Trichloro-1,2,2-trifluoroethane
1,1,2-Trichloro-1,2,2-trifluoroethane, also called trichlorotrifluoroethane or CFC-113, is a chlorofluorocarbon. It has the formula Cl2FC-CClF2. This colorless, volatile liquid is a versatile solvent.


1,1,2-Trichloro-1,2,2-trifluoroethane, Atmospheric reactions
CFC-113 is a very unreactive chlorofluorocarbon. It remains in the atmosphere about 90 years, sufficiently long that it will cycle out of the troposphere and into the stratosphere. In the stratosphere, CFC-113 can be broken up by ultraviolet radiation (where sunlight in the 190-225 nm (UV) range), generating chlorine radicals (Cl•), which initiate degradation of ozone requiring only a few minutes:


1,1,2-Trichloro-1,2,2-trifluoroethane, Atmospheric reactions
The process regenerates Cl• to destroy more O3. The Cl• will destroy an average of 100,000 O3 molecules during its atmospheric lifetime of 1–2 years. In some parts of the world, these reactions have significantly thinned the Earth's natural stratospheric ozone layer that shields the biosphere against solar UV radiation; increased UV levels at the surface can cause skin cancer or even blindness.


1,1,2-Trichloro-1,2,2-trifluoroethane, Uses
CFC-113 was one of the most heavily produced CFCs. In 1989, an estimated 250,000 tons were produced. It has been used as a cleaning agent for electrical and electronic components. CFC-113 is one of the three most popular CFCs, along with CFC-11 and CFC-12.


1,1,2-Trichloro-1,2,2-trifluoroethane, Uses
CFC-113’s low flammability and low toxicity made it ideal for use as a cleaner for delicate electrical equipment, fabrics, and metals. It would not harm the product it was cleaning, ignite with a spark or react with other chemicals.


1,1,2-Trichloro-1,2,2-trifluoroethane, Uses
CFC-113 in laboratory analytics has been replaced by other solvents.


1,1,2-Trichloroethane
1,1,2-Trichloroethane, or 1,1,2-TCA, is an organochloride solvent with the molecular formula C2H3Cl3. It is a colourless, sweet-smelling liquid that does not dissolve in water, but is soluble in most organic solvents. It is an isomer of 1,1,1-trichloroethane.


1,1,2-Trichloroethane
It is used as a solvent and as an intermediate in the synthesis of 1,1-dichloroethane.


1,1,2-Trichloroethane
1,1,2-TCA is a central nervous system depressant and inhalation of vapors may cause dizziness, drowsiness, headache, nausea, shortness of breath, unconsciousness, or cancer.


1,1,2-Trichloroethane, Toxicology
Trichloroethane may be harmful by inhalation, ingestion and skin contact. It is a respiratory and eye irritant. Although no definitive studies currently exist, trichloroethane should be treated as a potential carcinogen since laboratory evidence suggests that low molecular weight chlorinated hydrocarbons may be carcinogenic.


1,1,2-Trichloroethane, Toxicology
The Occupational Safety and Health Administration and National Institute for Occupational Safety and Health have set occupational exposure limits to 1,1,2-Trichloroethane at 10 ppm over an eight-hour time-weighted average. It is considered to be a potential occupational carcinogen.


1,1,3,3-Tetramethoxypropane
1,1,3,3-Tetramethoxypropane is an organic compound with the formula CH2(CH(OCH3)2)2. A colorless liquid, it is a protected form of malondialdehyde, a usefully reactive reagent that has poor storage properties.


1,1,3,3-Tetramethyl-1,3-divinyldisiloxane
1,1,3,3-Tetramethyl-1,3-divinyldisiloxane is the organosilicon compound with the formula O(SiMe2CH=CH2)2 (Me = methyl). Usually referred to as tetramethyldivinyldisiloxane, it is a colorless liquid that is employed as a ligand in organometallic chemistry and homogeneous catalysis. The ligand is a component of Karstedt's catalyst. Tetramethyldivinyldisiloxane was first prepared by hydrolysis of vinyldimethylmethoxysilane, (CH2=CH)Me2SiOMe.


1,1,3,3-Tetramethylguanidine
Tetramethylguanidine is an organic compound with the formula HNC(N(CH3)2)2. This colourless liquid is a strong base, as judged by the high pKa of it conjugate acid.


1,1,3,3-Tetramethylguanidine
It was originally prepared from tetramethylthiourea via S-methylation and amination, but alternative methods start from cyanogen iodide.


1,1,3,3-Tetramethylguanidine, Uses
TMG is mainly used as a strong, non-nucleophilic base for alkylations, often as a substitute for the more expensive DBU and DBN. Since it is highly water-soluble, it is easily removed from mixtures in organic solvents. It is also used as a base-catalyst in the production of polyurethane.


1,1,3-Trichloropropene
1,1,3-Trichloropropene is a compound of carbon, hydrogen, and chlorine. The structure is like propene, but in this compound, three hydrogen atoms are changed into chlorine atoms.


1,1,3-Trichloropropene
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1,1-Bis(chloromethyl)ethylene
1,1-Bis(chloromethyl)ethylene is the organic compound with the formula CH2=C(CH2Cl)2. It is a colorless liquid. Featuring two allylic chloride substituents, it is dialkylating agent.


1,1-Bis(chloromethyl)ethylene, Synthesis and reactions
It is prepared from pentaerythritol via a multistep procedure, beginning with the partial chlorination. The compound reacts with diiron nonacarbonyl to give the complex of trimethylenemethane Fe(η4-C(CH2)3)(CO)3. It is also a precursor to [1.1.1]-propellane.


1,1-Dibromoethane
1,1-Dibromoethane is a clear, slightly brown, flammable chemical compound. It is classified as the organobromine compound, and has the chemical formula C2H4Br2 and it is a position isomer of 1,2-dibromoethane. It is commonly seen in industrial chemistry, where it is used as a fuel additive. It is also used as a grain and soil fumigant for insect control.


1,1-Dibromoethane, Synthesis
1,1-Dibromoethane is synthesized through addition of hydrogen bromide onto vinyl bromide with absence of peroxide radical.


1,1-Dibromoethane, Safety
1,1-Dibromoethane is considered as a mild toxic compound, especially with bromines attached as substituents. Bromines on the ethane are strong oxidizing agents. If absorbed through inhalation, 1,1-dibromoethane could potentially cause neuronal effects, tissue damage, and bromism.


1,1-Dichloro-1-fluoroethane
1,1-Dichloro-1-fluoroethane is a haloalkane with the formula C2H3Cl2F. It is one of the three  isomers of dichlorofluoroethane. It belongs to the hydrochlorofluorocarbon (HCFC) family of man-made compounds that contribute significantly to both ozone depletion and global warming when released into the environment.


1,1-Dichloro-1-fluoroethane, Physiochemical properties
1,1-Dichloro-1-fluoroethane can be a non-flammable, colourless liquid under room-temperature atmospheric conditions. The compound is very volatile with a boiling point of 32°C. Its critical temperature is near 204°C. Its smell has been described as "usually ethereal" (like ether).


1,1-Dichloro-1-fluoroethane, Production and use
1,1-Dichloro-1-fluoroethane is mainly used as a solvent and foam blowing agent under the names R-141b and HCFC-141b. It is a class 2 ozone depleting substance undergoing a global phaseout from production and use under the Montreal Protocol since the late 1990's. It is being replaced by HFCs within some applications.


1,1-Dichloro-1-fluoroethane, Environmental effects
The concentration of HCFC-141b in the atmosphere grew to near 25 parts per trillion by year 2016. It has an ozone depletion potential (ODP) of 0.12. This is low compared to the ODP=1 of trichlorofluoromethane (CFC-11, R-11), which also grew about ten times more abundant in the atmosphere prior to introduction of HFC-141b and subsequent adoption of the Montreal Protocol.


1,1-Dichloro-1-fluoroethane, Environmental effects
HFC-141b is also a minor but potent greenhouse gas. It has an estimated lifetime of about 10 years and a 100-year global warming potential ranging 725 to 2500. This compares to the GWP=1 of carbon dioxide, which had a much greater atmospheric concentration near 400 parts per million in year 2020.


1,1-Dichloroethane
1,1-Dichloroethane is a chlorinated hydrocarbon. It is a colorless oily liquid with a chloroform-like odor. It is not easily soluble in water, but miscible with most organic solvents.


1,1-Dichloroethane
Large volumes of 1,1-dichloroethane are manufactured, with annual production exceeding 1 million pounds in the United States. It is mainly used as a feedstock in chemical synthesis, chiefly of 1,1,1-trichloroethane. It is also used as a solvent for plastics, oils and fats, as a degreaser, as a fumigant in insecticide sprays, in halon fire extinguishers, and in cementing of rubber. It is used in manufacturing of high-vacuum resistant rubber and for extraction of temperature-sensitive substances. Thermal cracking at 400–500 °C and 10 MPa yields vinyl chloride. In the past, 1,1-dichloroethane was used as a surgical inhalational anesthetic.


1,1-Dichloroethane, Safety
1,1-dichloroethane has been on the California Proposition 65 list of known carcinogens since 1990.


1,1-Dichloroethane, Safety
In the atmosphere, 1,1-dichloroethane decomposes with half-life of 62 days, chiefly by reaction of photolytically produced hydroxyl radicals.


1,1-Dichloroethene
1,1-Dichloroethene, commonly called 1,1-dichloroethylene or vinylidene chloride or 1,1-DCE, is an organochloride with the molecular formula C2H2Cl2. It is a colorless liquid with a sharp odor. Like most chlorocarbons, it is poorly soluble in water, but soluble in organic solvents. 1,1-DCE was the precursor to the original cling-wrap, Saran, for food, but this application has been phased out.


1,1-Dichloroethene, Production
1,1-DCE is produced by dehydrochlorination of 1,1,2-trichloroethane, a relatively unwanted byproduct in the production of 1,1,1-trichloroethane and 1,2-dichloroethane. The conversion is a base-catalyzed reaction which uses either NaOH or Ca(OH)2 with temperature ca. 100 °C.


1,1-Dichloroethene, Production
The gas phase reaction, without the base, would be more desirable but is less selective.


1,1-Dichloroethene, Applications
1,1-DCE is mainly used as a comonomer in the polymerization of vinyl chloride, acrylonitrile, and acrylates. It is also used in semiconductor device fabrication for growing high purity silicon dioxide (SiO2) films.


1,1-Dichloroethene, Applications, Polyvinylidene chloride
As with many other alkenes, 1,1-DCE can be polymerised to form polyvinylidene chloride. A very widely used product, cling wrap, or Saran was made from this polymer. During the 1990s research suggested that, in common with many chlorinated carbon compounds, Saran posed a possible danger to health by leaching, especially on exposure to food in microwave ovens. Since 2004, therefore cling wrap's formulation has changed to a form of polyethylene.


1,1-Dichloroethene, Safety
The health effects from exposure to 1,1-DCE are primarily on the central nervous system, including symptoms of sedation, inebriation, convulsions, spasms, and unconsciousness at high concentrations.


1,1-Dichloroethene, Safety
International Agency for Research on Cancer has put vinylidene chloride in  Class 2B, meaning possibly carcinogenic to humans. National Institute for Occupational Safety and Health considers 1-DCE a potential occupational carcinogen. It is also listed as a chemical known to the state of California to cause cancer and birth defects.


1,1-Diethoxyethane
1,1-Diethoxyethane (acetaldehyde diethyl acetal) is a major flavoring component of distilled beverages, especially malt whisky and sherry. Although it is just one of many compounds containing an acetal functional group, this specific chemical is sometimes called simply acetal.


1,1-Difluoroethane
1,1-Difluoroethane, or DFE, is an organofluorine compound with the chemical formula C2H4F2. This colorless gas is used as a refrigerant, where it is often listed as R-152a (refrigerant-152a) or HFC-152a (hydrofluorocarbon-152a). It is also used as a propellant for aerosol sprays and in gas duster products. As an alternative to chlorofluorocarbons, it has an ozone depletion potential of zero, a lower global warming potential (124) and a shorter atmospheric lifetime (1.4 years).


1,1-Difluoroethane, Production
1,1-Difluoroethane is a man-made substance that is produced by the mercury-catalyzed addition of hydrogen fluoride to acetylene:


1,1-Difluoroethane, Production
The intermediate in this process is vinyl fluoride (C2H3F), the monomeric precursor to polyvinyl fluoride.


1,1-Difluoroethane, Uses
With a relatively low global warming potential (GWP) index of 124 and favorable thermophysical properties, 1,1-difluoroethane has been proposed as an environmentally friendly alternative to R134a. Despite its flammability, R152a also presents operating pressures and volumetric cooling capacity (VCC) similar to R134a so it can be used in large chillers or in more particular applications like heat pipe finned heat exchangers.


1,1-Difluoroethane, Uses
Furthermore, 1,1-difluoroethane is also commonly used in gas dusters and many consumer aerosol products, especially those subject to stringent volatile organic compound (VOC) requirements.


1,1-Difluoroethane, Uses
The molecular weight of difluoroethane is 66, making it a useful and convenient tool for detecting vacuum leaks in GC-MS systems. The cheap and freely available gas has a molecular weight and fragmentation pattern (base peak 51 m/z in typical EI-MS, major peak at 65 m/z) distinct from anything in air. If mass peaks corresponding to 1,1-difluoroethane are observed immediately after spraying a suspect leak point, leaks may be identified.


1,1-Difluoroethane, Safety
Difluoroethane is an intoxicant and precipitates fatal cardiac arrhythmia. Several reports of fatal car crashes have been linked to drivers huffing 1,1-difluoroethane. Actress Skye McCole Bartusiak died due to combined effects of difluoroethane and other drugs. Because of inhalant abuse, a bitterant is added to some brands; however even this measure is not legally required and has not prevented widespread use of this product as a drug.


1,1-Difluoroethane, Safety
In a DuPont study, rats were exposed to up to 25,000 ppm (67,485 mg/m3) for six hours daily, five days a week for two years. This has become the no-observed-adverse-effect level for this substance. Prolonged exposure to 1,1-difluoroethane has been linked in humans to the development of coronary disease and angina.


1,1-Difluoroethane, Environmental abundance
Most production, use, and emissions of HFC-152a have occurred within Earth's more industrialized and populated northern hemisphere following the substance's widespread introduction in the 1990s. Its concentration in the northern troposphere reached an annual average of about 10 parts per trillion by year 2011. The concentration of HFC-152a in the southern troposphere is about 50% lower due to its removal rate (i.e. lifetime) of about 1.5 years being similar in magnitude to the global atmospheric mixing time of one to two years.


1,1-Difluoroethylene
1,1-Difluoroethylene, also known as vinylidene fluoride, is a hydrofluoroolefin. It is a flammable gas. Global production in 1999 was approximately 33,000 metric tons. It is primarily used in the production of fluoropolymers such as polyvinylidene fluoride.


1,1-Difluoroethylene, Preparation
1,1-Difluoroethylene can be prepared by elimination reaction from a 1,1,1-trihaloethane compound, for example, loss of hydrogen chloride from 1-chloro-1,1-difluoroethane:.


1,1-Dihydroxyethene
1,1-Dihydroxyethene is an organic compound consisting of two hydroxy groups as substituents on the same carbon atom of an ethene chain. The chemical is also called ketene hydrate because it is the carbonyl hydrate of ketene. Its structure can also be considered as the enol form of acetic acid. This compound is likely a key intermediate in the hydration reaction that converts ketene into acetic acid. The analysis of the possible pathways for this reaction has been cited as an example of the importance of considering activation energy of each mechanistic step. The hydration of the carbonyl of ketene, which formally involves an addition reaction of one water molecule onto the carbonyl group, is likely catalyzed by a second water molecule. The compound has now been synthesized and identified spectroscopically.


1,1-Diiodoethane
1,1-Diiodoethane is an organic saturated haloalkane containing iodine with formula CH3CHI2.


1,1-Diiodoethane, Preparation
1,1-diiodoethane can be synthesized from gem-dihaloalkanes. The starting material is 1,1-dichloroethane, and iodoethane is a source of iodine. In the presence of aluminium trichloride, 1,1-dichloroethane will converted to 1,1-diiodoethane.


1,1-Diiodoethane, Preparation
To be specific, mix 0.4 mol (~39.6 g) of 1,1-dichloroethane with 1.2 mol(~187 g) of ethyl iodide, and ~2.0 g of aluminum chloride. Heat for three hours using steam bath. Then, wash the mixture with H2O and NaHSO3 respectively, and dry with MgSO4. By boiling at 76-76 °C and 25 mmHg, about 67.3 g of product will be received when distilled.


1,1-Diiodoethane, Preparation
The alternative method, which does not require 1,1-dichloroethane, is the reaction of iodine, triethylamine and hydrazone of acetaldehyde. Using 1 mol of acetaldehyde, about 95 g, which is 34% from acetaldehyde, of 1,1-diiodoethane formed.


1,1-Diiodoethane, Application
1,1-diiodoethane is commonly used as a reactant in reaction such as SN2. The following are some examples of SN2 reaction using 1,1-diiodoethane as a reactant.


1,1-Diiodoethane, Application
Moreover, is can also be used as a reactant in enolate substitution reaction as the following examples.


1,1-Dimethyldiborane
1,1-Dimethyldiborane is the organoboron compound with the formula (CH3)2B(μ-H)2BH2. A pair of related 1,2-dimethyldiboranes are also known. It is a colorless gas that ignites in air.


1,1-Dimethyldiborane, Formation
The methylboranes were first prepared by H. I. Schlesinger and A. O. Walker in the 1930s. Methylboranes are formed by the reaction of diborane and trimethylborane. This reaction produces four different substitution of methyl with hydrogen on diborane. Produced are 1-methyldiborane, 1,1-dimethyldborane, 1,1,2-trimethyldiborane, and 1,1,2,2-tetramethyldiborane.


1,1-Dimethyldiborane, Formation
Tetramethyl lead reacts with diborane in a 1,2-dimethoxyethane solvent at room temperature to make a range of methyl substituted diboranes, ending up at trimethylborane, but including 1,1-dimethyldiborane, and trimethyldiborane. The other outputs of the reaction are hydrogen gas and lead metal.


1,1-Dimethyldiborane, Formation
Other methods to form methyldiboranes include heating trimethylborane with hydrogen. Alternatively trimethylborane reacts with borohydride salts with in the presence of hydrogen chloride, aluminium chloride, or boron trichloride. If the borohydride is sodium borohydride, then methane is a side product. If the metal is lithium then no methane is produced. dimethylchloroborane and methyldichloroborane are also produced as gaseous products.


1,1-Dimethyldiborane, Formation
When Cp2Zr(CH3)2 reacts with borane dissolved in tetrahydrofuran, a borohydro group inserts into the zirconium carbon bond, and methyl diboranes are produced.


1,1-Dimethyldiborane, Formation
In ether dimethylcalcium reacts with diborane to produce dimethyldiborane and calcium borohydride:


1,1-Dimethyldiborane, Formation
Gas chromatography can be used to determine the amounts of the methyl boranes in a mixture. The order they elute are diborane, monomethyldiborane, trimethylborane, 1,1-dimethyldiborane, 1,2-dimethyldiborane, trimethyldiborane, and finally tetramethyldiborane.


1,1-Dimethyldiborane, Selected properties
1,1-Dimethyldiborane has a dipole moment of 0.87 d. The predicted heat of formation for the liquid is ΔH0f=-31 kcal/mol, and for the gas -25 kcal/mol. Heat of vapourisation was measured at 5.5 kcal/mol.


1,1-Dimethyldiborane, Reactions
At −78.5 °C, methyldiborane disproportionates slowly, first to diborane and 1,1-dimethyldiborane. In solution methylborane is more stable against disproportionation than dimethylborane.


1,1-Dimethyldiborane, Reactions
Trimethyldiborane partially disproportionates over a period of hours at room temperature to yield tetramethyldiborane and 1,2-dimethyldiborane. Over a period of weeks 1,1-dimethyldiborane appears as well.


1,1-Dimethyldiborane, Reactions
Gentler oxidation of 1,1-dimethyldiborane at 80 °C yields 2,5-dimethyl-1,3,4-trioxadiboralane, a volatile liquid that contains a ring of two boron and three oxygen atoms. An intermediate in this reaction is two molecules of dimethylborylhydroperoxide (CH3)2BOOH. (CAS 41557-62-5) When methyldiborane is oxidised around 150 °C a similar substance methyltrioxadiboralane is produced. At the same time dimethyltrioxadiboralane and trimethylboroxine are also formed, and also hydrocarbons, diborane, hydrogen, and dimethoxyborane (dimethyl methylboronic ester).


1,1-Dimethylethylenediamine
1,1-Dimethylethylenediamine is the organic compound with the formula (CH3)2N)CH2CH2NH2. It is a colorless liquid with a fishy odor. It features one primary amine and a tertiary amine. It is used to prepare a chelating diamine-containing ligands for the preparation of metal catalysts. It is a precursor to the drug chloropyramine.


1,1-Diphenylethylene, Properties
1,1-Diphenylethylene mediates the radical polymerization of methyl acrylate or styrene. Meditation by 1,1-Diphenylethylene generates low molecular weight polymer by a termination reaction. Dibenzofulvene is an analogue of a 1,1-Diphenylethylene.


1,1-Diphenylethylene, Synthesis
1,1-Diphenylethylene is technical prepared by alkylating benzene by styrene in presence of a zeolite beta and subsequent dehydrogenation.


1,1′-Bi-2-naphthol
1,1′-Bi-2-naphthol (BINOL) is an organic compound that is often used as a ligand for transition-metal catalysed asymmetric synthesis. BINOL has axial chirality and the two enantiomers can be readily separated and are stable toward racemisation. The specific rotation of the two enantiomers is ±35.5° (c = 1 in THF). BINOL is a precursor for another chiral ligand called BINAP. The volumetric mass density of the two enantiomers is 0.62 g cm−3.


1,1′-Bi-2-naphthol, Preparation
The organic synthesis of BINOL is not a challenge as such but the preparation of the individual enantiomers is.


1,1′-Bi-2-naphthol, Preparation
(S)-BINOL can be prepared directly from an asymmetric oxidative coupling of 2-naphthol with copper(II) chloride. The chiral ligand in this reaction is (S)-(+)-amphetamine.


1,1′-Bi-2-naphthol, Preparation
Racemic BINOL can also be produced using iron(III) chloride as an oxidant. The mechanism involves complexation of iron(III) into the hydroxyl, followed by a radical coupling reaction of the naphthol rings initiated by iron(III) reducing into iron(II).


1,1′-Bi-2-naphthol, Preparation
Optically active BINOL can also be obtained from racemic BINOL by optical resolution. In one method, the alkaloid N-benzylcinchonidinium chloride forms a crystalline inclusion compound. The inclusion compound of the (S)-enantiomer is soluble in acetonitrile but that of the (R)-enantiomer is not. In another method BINOL is esterified with pentanoyl chloride. The enzyme cholesterol esterase hydrolyses the (S)-diester but not the (R)-diester. The (R)-dipentanoate is hydrolysed in a second step with sodium methoxide. The third method employs HPLC with chiral stationary phases.


1,1′-Bi-2-naphthol, BINOL derivatives
Aside from the starting materials derived directly from the chiral pool, (R)- and (S)-BINOL in high enantiopurity (>99% enantiomeric excess) are two of the most inexpensive sources of chirality for organic synthesis, costing less than US$0.60 per gram when purchased in bulk from chemical suppliers. As a consequence, it serves as an important starting material for other sources of chirality for stereoselective synthesis, both stoichiometric and substoichiometric (catalytic).


1,1′-Bi-2-naphthol, BINOL derivatives
Many important chiral ligands are constructed from the binaphthyl scaffold and ultimately derived from BINOL as a starting material, BINAP being one of the most well known and important.


1,1′-Bi-2-naphthol, BINOL derivatives
The compound aluminium lithium bis(binaphthoxide) (ALB) is prepared by reaction of BINOL with lithium aluminium hydride. In a different stoichiometric ratio (1:1 BINOL/LiAlH4 instead of 2:1), the chiral reducing agent BINAL (lithium dihydrido(binaphthoxy)aluminate) is produced.


1,1′-Bi-2-naphthol, BINOL derivatives
It has been employed in an asymmetric Michael reaction with cyclohexenone and dimethyl malonate:


1,2,3 Soleils
1, 2, 3 Soleils (1, 2, 3 Suns) is a live album performed by Algerian artists Rachid Taha, Khaled and Faudel, widely hailed as the three masters of raï music. The concert, a unique event, took place in 1998 in Palais Omnisports de Paris-Bercy in Paris, and the songs consisted of the most famous from all three artists plus a few Algerian classics. All 23 were divided into two discs, produced and arranged by Steve Hillage, released by Barclay in 1999.


1,2,3 Soleils
The album has attained 2x gold certification and the DVD video has attained gold certification from Syndicat National de l'Edition Phonographique.


1,2,3 Soleils
A shortened US one Compact Disc release of the album was released by Ark 21.


1,2,3,3,3-Pentafluoropropene
1,2,3,3,3-Pentafluoropropene is the unsaturated fluorocarbon with the formula HFC=C(F)CF3. This colorless gas is of interest as a precursor to hydrofluoroolefins (HFOs), which are used as refrigerants in air conditioners. Of the methods reported for its synthesis, one route involves dehydrofluorination of 1,1,2,3,3,3-hexafluoropropane. The compound exists as a mixture of E- and Z-isomers.


1,2,3,4,5-Cyclopentanepentol
1,2,3,4,5-Cyclopentanepentol, also named cyclopentane-1,2,3,4,5-pentol or 1,2,3,4,5-pentahydroxycyclopentane is a chemical compound with formula C5H10O5 or (–CHOH–)5, whose molecule consists of a ring of five carbon atoms (a cyclopentane skeleton), each connected to one hydrogen and one hydroxyl group. The unqualified term "cyclopentanepentol" usually refers to this compound. There are four distinct stereoisomers with this same structure.


1,2,3,4,5-Cyclopentanepentol
The compound is a five-fold alcohol of cyclopentane, and technically a cyclic sugar alcohol (a cyclitol). However it is very rarely found in nature, and therefore it has received much less attention than the ubiquitous six-carbon version, inositol.


1,2,3,4,5-Cyclopentanepentol, Isomers
There are four distinct stereoisomers of cyclopentane-1,2,3,4,5-pentol, distinguished by the position of the hydroxyls relative to the mean plane of the ring. All have a plane of symmetry, and therefore are not chiral. One naming convention for the isomers labels each carbon number 1-5 with "α" for the side of the ring plane with most hydroxyls (three or more), and "β" for the other side. Another convention lists the hydroxyls on the majority side and then those on the minority side, with the two groups separated by a slash (and a "0" is written when the second list would be empty).


1,2,3,4,5-Cyclopentanepentol, Isomers
The last three isomers interconvert by heating them at about 104 °C with 95% acetic acid in the presence of a strong acid. The conversion between 1,2,3,4/5 and 1,2,3/4,5 is faster and entails the hydrogen and hydroxyl switching places on either of the two carbon atoms located between an "α" and a "β" position. The formation of 1,2,4/3,5 is much slower and equilibrium is reached only after many days. The relative stabilities are 1,2,4/3,5 > 1,2,3/4,5 > 1,2,3,4/5, with equilibrium ratios 72 : 17.5 : 10.5.


1,2,3,4,5-Cyclopentanepentol, Isomers
The isomers can be identified qualitatively by their mobility in paper ionophoresis in a solution of calcium acetate and acetic acid, and revealed with a manganese sulfate/potassium permanganate reagent. The mobilities of the isomers, relative to that of cis-inositol, are 0.95 (12345/0), 0.44 (1234/5), 0.18 (123/45), and 0.04 (124/35). The variation is attributed to the formation of chelates with the calcium cations, with varying strengths depending on the number of hydroxyl pairs that can bind to the cation. Similar results can be obtained with lanthanum cations and thin-layer chromatography.


1,2,3,4,5-Cyclopentanepentol, Isomers
Mass spectrometry of the compound generates mainly the ion HO–CH=CH=CH=O+H (mass-charge ratio 73) and a neutral radical C2H5O•.


1,2,3,4,5-Cyclopentanepentol, Derivatives
Trteatment of the derivative 3,4,5-tri-O-acetyl-1,2-O-ethylidene-(1,2,4/3,5)-cyclopentanepentol with triphenylcarbenium tetrafluoroborate [(C6H5)3C]+[BF4]− to yield the cation 3,4,5-tri-O-acetyl-(1,2,4/3,5)-cyclopentanepentol-1,2-O-acetoxonium, which exhibits a peculiar 10-stage cyclic rearrangement.


1,2,3,4,5-Cyclopentanepentol, Derivatives
Cyclopentanepentols form dihydrogenphosphate esters analogous to inositol's phytic acid esters.


1,2,3,4,5-Cyclopentanepentol, Derivatives
The related compound 1,2,3,4,5-pentakis(hydroxymethyl)-cyclopentane (a colourless viscous oil, soluble in tert-butanol and DMSO) was synthesized in 1985 by L. M. Tolbert and others. It was hoped that dehydrative dimerization of this product would yield dodecahedrane.


1,2,3,4,5-Cyclopentanepentol, Natural occurrence
Organic compounds similar to (and possibly mimicking) glycoglycerolipids, with a 1,2,4/3,5-cyclopentanepentol group connected to the glycerol core in place of the sugar group, have been found in several genera of marine sponges with widely separate ranges.


1,2,3,4,5-Cyclopentanepentol, Natural occurrence
Calditol is a substance found in the archaeobacteria of the order Sulfolobales. It is an ether that can be viewed as the condensation of glycerol and 3α-hydroxymethyl-1α,2α,3β,4α,5β-hydroxy cyclopentane, forming an ether bridge –O– between the 1-carbon of the former and the 4-carbon of the latter. Its seems to protects the cells in acidic environments.


1,2,3,4,5-Cyclopentanepentol, Natural occurrence
Trace amounts of cyclopentanepentol were identified in some plants, such as the red flower calyces of Hibiscus sabdariffa (roselle); the plant Maclura pomifera (Osage orange); and the cyanobacterium Oscillatoria willei as well as in the products of its hydropyrolysis.


1,2,3,4,5-Cyclopentanepentol, History
The 1,2,4/3,5 isomer was briefly described in 1963 by H. Z. Sable and others. In 1968, Th. Posternak reported observation of 1,2,3,4/5 and 1,2,3/4,5, without the synthesis method. Better synthesis methods for these three were published by S. J. Angyal and B. M. Luttrell in 1970. Alternative methods for 1,2,3,4/5 and 1,2,3/4,5 were published in the same year by G. Wolczunowicz and others. The remaining all-cis isomer (1,2,3,4,5/0) was synthesized in 1971 by F. G. Cocu and Posternak.


1,2,3,4,5-Pentakis(4-butylphenyl)-1,3-cyclopentadiene
1,2,3,4,5-Pentakis(4-butylphenyl)-1,3-cyclopentadiene is an organochemical compound from the diene group and a cyclopentadiene derivative. The anion of this compound is used as a sterically demanding ligand, often abbreviated as Cp[BIG], in the organometallic chemistry of sandwich compounds.


1,2,3,4,5-Pentakis(4-butylphenyl)-1,3-cyclopentadiene, Preparation
1,2,3,4,5-Pentakis(4-butylphenyl)-1,3-cyclopentadiene can be prepared in a one-step reaction by the palladium-catalyzed reaction of Zirconocene dichloride with 4-n-butylbenzene bromide.


1,2,3,4,5-Pentakis(4-butylphenyl)-1,3-cyclopentadiene, Reactions
1,2,3,4,5-Pentakis(4-butylphenyl)-1,3-cyclopentadiene reacts directly with a range of organometallic compounds or in reduced form as a sodium or potassium compound with the salts of main-group and transition metals. The resulting metallocenes, in contrast to the unsubstituted Pentaphenylcyclopentadienyl complexes are in various solvents readily soluble. The perarylated metallocenes, such as Samarium, sometimes exhibit unusual stability. This is likely to be explained by hydrogen bonds between the substituents. The reaction of 1,2,3,4,5-pentakis(4-butylphenyl)-1,3-cyclopentadiene with strong basic strontium and barium compounds provides the corresponding coplanar sandwich compounds.


1,2,3,4,6-Pentagalloyl glucose
1,2,3,4,6-Pentagalloylglucose is the pentagallic acid ester of glucose. It is a gallotannin and the precursor of ellagitannins.


1,2,3,4,6-Pentagalloyl glucose, Natural occurrence
1,2,3,4,6-Pentagalloyl glucose can be found in Punica granatum (pomegranate), Elaeocarpus sylvestris, Rhus typhina (Staghorn sumac), Paeonia suffruticosa (Tree Peony),., Mangifera indica (mango)  and Bouea macrophylla Griffith (maprang).


1,2,3,4,6-Pentagalloyl glucose, Biosynthesis
The enzyme beta-glucogallin-tetrakisgalloylglucose O-galloyltransferase uses 1-O-galloyl-beta-D-glucose and 1,2,3,6-tetrakis-O-galloyl-beta-D-glucose to produce D-glucose and pentagalloyl glucose.


1,2,3,4,6-Pentagalloyl glucose, Metabolism
Tellimagrandin II is formed from pentagalloyl glucose by oxidative dehydrogenation and coupling of 2 galloyl groups.


1,2,3,4,6-Pentagalloyl glucose, Metabolism
β-glucogallin: 1,2,3,4,6-pentagalloyl-β-d-glucose galloyltransferase is an enzyme found in the leaves of Rhus typhina that catalyzes the galloylation of 1,2,3,4,6-penta-O-galloyl-β-D-glucose to 3-O-digalloyl-1,2,4,6-tetra-O-galloyl-β-d-glucose (hexa-galloylglucose).


1,2,3,4,6-Pentagalloyl glucose, Chemistry
Pentagalloyl glucose can undergo oxidation reactions which are depending on the pH.


1,2,3,4,6-Pentagalloyl glucose, Research
Pentagalloyl glucose has been studied for its potential use as an antimicrobial, anti-inflammatory, anticarcinogenic, antidiabetic, and antioxidant. It has also been studied for radioprotection. This compound helps stabilize the elastin and collagen in vascular tissues and restores the biomechanical properties of arterial ECM. In addition, pentagalloyl glucose has shown to reduce arterial calcification and helps promote extracellular matrix preservation in animal models of abdominal aortic aneurysm. In vitro studies with  mouse C2C12 myoblast cells have shown the PGG helps in lowering reactive oxygen species (ROS) and  matrix metalloproteinase-2 (MMP-2) expression in a dose-dependent manner.


1,2,3,4-Cyclohexanetetrol
1,2,3,4-Cyclohexanetetrol (also named cyclohexane-1,2,3,4-tetrol, 1,2,3,4-tetrahydroxycyclohexane, or ortho-cyclohexanetetrol) is an organic compound whose molecule can be described as a cyclohexane with four hydroxyl (OH) groups substituted for hydrogen atoms on four consecutive carbon atoms. Its formula can be written C6H12O4, C6H8(OH)4, or (–CH(OH)–)4(–CH2–)2.


1,2,3,4-Cyclohexanetetrol
There are 10 isomers with this same structural formula, which are among the 43 isomers of cyclohexanetetrol. They are all polyols, more specifically tetrols and cyclitols. Some of them have biologically important roles in some organisms.


1,2,3,4-Cyclohexanetetrol, Isomers and nomenclature
There are 10 different isomers of this compound, that differ in the orientation of the four hydroxyls relative to the mean plane of the ring. They can be denoted by the letter "α" or "β" after each carbon index ("2α","2β","4β", etc. ), to indicate the corresponding side of the plane relative to the 1-hydroxyl; or by listing all the "α" indices, then a slash "/", then the "β" indices (or "0" if the second list is empty).


1,2,3,4-Cyclohexanetetrol, History
Synthesis of 1,2,3,4-cyclohexanetretrols was first reported in 1933 by Pierre Bedos and Adrien Ruyer, by hydrolysis of 1,2;3,4-diepoxy-cyclohexane. They separated the reaction products into two isomers, with melting points 210C (tetrabenzoate: 146C) and 187C (tetrabenzoate: 260C), respectively, in 1:2 ratio.


1,2,3,4-Cyclohexanetetrol, History
In 1953, Théodore Posternak and H. Friedli obtained the achiral 1,4/2,3 isomer and racemic mixtures of the 1,2/3,4, 1,3/2,4, and 1,2,4/3 isomers. By biochemical oxydation, they removed the D- enentiomers of the last three, leaving the L- enantiomers.


1,2,3,4-Cyclohexanetetrol, History
Posternak and Reymond observed in 1953 that the 1,3/2,4 isomer (D and L forms) is not attacked by a certain strain of A. suboxydans, whereas all the others were metabolized with consumption of 1 atom of oxygen (possibly by formation of a ketone-triol), except the 1,2/3,4 isomer (D and L) that consumed 2 atoms.


1,2,3,4-Cyclohexanetetrol, History
In 1955, Posternak and Reymond studied the oxydation of the 1,4/2,3 isomer (dihydro-conduritol) by Acetobacter suboxydans, producing a trihydroxyketone. They also characterized the chiral isomers 1,3/2,4, 1,2,3/4,and 1,2,4/3.


1,2,3,4-Cyclohexanetetrol, Synthesis
Methods which have been employed for the preparation of 1,2,3,4-cyclohexanetetrols include: reduction or hydrogenation of (1) cyclohexenetetrols, (2) tri-hydroxycyclohexanones, (3) pentahydroxycyclohexanones (inososes), (4) hydroxylated aromatics, or (5) hydroxylated quinones; the (6) hydrogenolysis of dibromocyclohexanetetrols; the (7) hydration of diepoxycyclohexanes; and the hydroxylation of (8) cyclohexadienes or (9) cyclohexenediols.


1,2,3,4-Cyclohexanetetrol, Synthesis
In 2007, Peter Valente and others described the preparation of achiral 1,4/2,3-cyclohexanetetrol (toxocarol) from  2,3-dioxabicyclo[2.2.2]oct-5-ene, a cyclohexene with a peroxide bridge (–O–O–) replacing hydrogens in carbons 3 and 6. The previous route was reduction of the peroxide brige to yield 3α,6α-dihydroxy cyclohexene, followed by di-hydoxylation of the double bond; which yielded a mixture of the 1,4/2,3 and 1,2,3,4/0 isomers. The authors found that, by reversing the order of the two steps, they could obtain 1,4/2,3 in 80% yield.


1,2,3,4-Tetraphenylnaphthalene
1,2,3,4-Tetraphenylnaphthalene is a polycyclic aromatic hydrocarbon commonly prepared in the undergraduate teaching laboratory as an introduction to the Diels-Alder reaction, in this case between benzyne, which acts as the dienophile, (generated in situ) and tetraphenylcyclopentadienone, which acts as the diene. It has two crystalline forms, and therefore has two different melting points.


1,2,3,5-Tetrahydroxybenzene
It is a metabolite in the degradation of 3,4,5-trihydroxybenzoate (gallic acid) by Eubacterium oxidoreducens.


1,2,3,5-Tetrahydroxybenzene
The enzyme pyrogallol hydroxytransferase uses 1,2,3,5-tetrahydroxybenzene and 1,2,3-trihydroxybenzene (pyrogallol), whereas its two products are 1,3,5-trihydroxybenzene (phloroglucinol) and 1,2,3,5-tetrahydroxybenzene.


1,2,3-Benzothiadiazole
1,2,3-Benzothiadiazole is a bicyclic aromatic chemical composed of a benzene ring that is fused to a 1,2,3-thiadiazole. A colorless solid, the compound is soluble in organic solvents.


1,2,3-Benzothiadiazole, Preparation
1,2,3-Benzothiadiazole is readily prepared by the diazotisation reaction of 2-aminothiophenol or its disulfide with sodium nitrite, as originally reported in 1887 and reviewed in several subsequent publications.


1,2,3-Benzothiadiazole, Preparation
By the Herz reaction anilines can be converted to benzothiadiazole. The method is attractive since less elaborate precursors (merely anilines) are required. Upon treatment with disulfur dichloride, the anilines give the intermediate 1,3,2-benzothiazathiolium salt, which is diazotised to complete the formation of a 1,2,3-benzothiadiazole. The parent system cannot be made this way, since the use of aniline in this reaction leads to formation of the 6-chloro derivative.


1,2,3-Benzothiadiazole, Structure and bonding
The molecule is planar. The N-N and S-N distances are respectively 128 and 171 picometers, indicative of multiple bond character. Like naphthalene, this heterocycle is a 10-electron system.


1,2,3-Benzothiadiazole, Reactions
1,2,3-benzothiadiazole is much less nucleophilic than naphthalene. Nitration is slow. For that reason, many of its simple derivatives have been made from 2-aminothiophenols already having additional substituents.


1,2,3-Benzothiadiazole, Reactions
1,2,3-benzothiadiazole is a very weak base and alkylation reactions give exclusively the 3-amino quaternary salt.


1,2,3-Benzothiadiazole, Applications
1,2,3-benzothiadiazole has been claimed to synergise insecticides including dicrotophos but has not been commercialised for that application. The only derivative to have found significant use is the fungicide acibenzolar-S-methyl.


1,2,3-Triazole
1,2,3-Triazole is one of a pair of isomeric chemical compounds with molecular formula C2H3N3, called triazoles, which have a five-membered ring of two carbon atoms and three nitrogen atoms. 1,2,3-Triazole is a basic aromatic heterocycle.


1,2,3-Triazole
Substituted 1,2,3-triazoles can be produced using the azide alkyne Huisgen cycloaddition in which an azide and an alkyne undergo a 1,3-dipolar cycloaddition reaction.


1,2,3-Triazole
It is a surprisingly stable structure compared to other organic compounds with three adjacent nitrogen atoms. However, flash vacuum pyrolysis at 500 °C leads to loss of molecular nitrogen (N2) leaving a three-member aziridine ring. Certain triazoles are relatively easy to cleave due to ring–chain tautomerism. One manifestation is found in the Dimroth rearrangement.


1,2,3-Triazole
1,2,3-Triazole finds use in research as a bioisostere in medicinal chemistry building block for more complex chemical compounds, including pharmaceutical drugs such as mubritinib and tazobactam.


1,2,3-Triazole
The 2H-1,2,3-triazole tautomer is the major form in aqueous solution.


1,2,3-Tribromopropane
1,2,3-Tribromopropane (TBP) is a toxic organic compound. It is a clear colorless to light yellow liquid.


1,2,3-Trichloropropane
1,2,3-Trichloropropane (TCP) is an organic compound with the formula CHCl(CH2Cl)2. It is a colorless liquid that is used as a solvent and in other specialty applications.


1,2,3-Trichloropropane, Production
1,2,3-Trichloropropane is produced the addition of chlorine to allyl chloride. TCP also may be produced as a by-product also is produced in significant quantities as an unwanted by-product of the production of other chlorinated compounds such as epichlorohydrin and dichloropropene.


1,2,3-Trichloropropane, Uses
Historically, TCP has been used as a paint or varnish remover, a cleaning and degreasing agent, and an solvent. It is also used as an intermediate in the production of hexafluoropropylene. It is a crosslinking agent for polysulfide polymers and sealants.


1,2,3-Trichloropropane, Effects of exposure
Humans can be exposed to TCP by inhaling its fumes or through skin contact and ingestion. TCP is recognized in California as a human carcinogen, and extensive animal studies have shown that it causes cancer. Short term exposure to TCP can cause throat and eye irritation and can affect muscle coordination and concentration. Long term exposure can affect body weight and kidney function.


1,2,3-Trichloropropane, Regulation, United States, Proposed federal regulation
As of 2013 TCP was not regulated as a contaminant by the federal government, but research shows that it could have severe health effects; only the state of California had significant regulation of this compound.


1,2,3-Trichloropropane, Regulation, United States, Proposed federal regulation
In a drinking water project  proposed by the United States Environmental Protection Agency (EPA), TCP was one of sixteen suspected human carcinogens being considered for regulation in 2011.


1,2,3-Trichloropropane, Regulation, United States, State regulation
Pre-1980s, agricultural use of chloropropane-containing soil fumigants for use as pesticides and nematicides was prevalent in the United States. Some soil fumigants, which contained a mixture of primarily 1,3-dichloropropene and 1,2-dichloropropane, and in which 1,2,3-TCP was a minor component, e.g., trade name of D-D, were marketed for the cultivation of various crops including citrus fruits, pineapples, soy beans, cotton, tomatoes, and potatoes. D-D was first marketed in 1943, but is no longer available in the United States, and has been replaced with Telone II, which was first available in 1956.


1,2,3-Trichloropropane, Regulation, United States, State regulation
Telone II reportedly contains as much as 99 percent 1,3-dichloropropene and up to 0.17 percent by weight 1,2,3-TCP (Zebarth et al., 1998). Before 1978, approximately 55 million pounds/year of 1,3-dichloropropene were produced annually in the United States, and approximately 20 million pounds/year of 1,2-dichloropropane and 1,2,3-TCP were produced as by-products in the production of 1,3-dichloropropene. Over 2 million pounds of pesticides containing 1,3-dichloropropene were used in California alone in 1978. Telone II is still used for vegetables, field crops, fruit and nut trees, grapes, nursery crops, and cotton.


1,2,3-Trichloropropane, Regulation, United States, State regulation
The California State Water Resources Control Board's Division of Drinking Water established an enforceable Maximum Contaminant Level (MCL) of 5 ng/L (parts per trillion). The state of Alaska has promulgated standards establishing cleanup levels for 1,2,3-trichloropropane contamination in soils and groundwater. The state of California considers 1,2,3-trichloropropane to be a regulated contaminant that must be monitored. The state of Colorado has also promulgated a groundwater standard although there is no drinking water standard.


1,2,3-Trichloropropane, Regulation, United States, State regulation
Although there is not much regulation on this substance, it has proved that TCP is a carcinogen in laboratory mice, and most likely a human carcinogen as well. On a federal scale, there is no MCL for this contaminant. The Permissible Exposure Limit (PEL) in occupational setting for air is 50 ppm or 300 mg/m3. The concentration in air at which TCP becomes an Immediate Danger to Life and Health (IDLH) is at 100 ppm. These regulations were reviewed in 2009.


1,2,3-Trichloropropane, TCP as an emerging contaminant
TCP does not contaminate soil. Instead, it leaks down into groundwater and settles at the bottom of the reservoir because TCP is more dense than water. This makes TCP in its pure form a DNAPL (Dense Nonaqueous Phase Liquid) and it is, therefore, harder to remove it from groundwater. There is no evidence that TCP can naturally decompose, but it might in favorable conditions. Groundwater remediation of TCP can occur through in situ chemical oxidation, permeable reactive barriers, and other remediation techniques. Several TCP remediation strategies have been studied and/or applied with varying degrees of success. These include extraction with granular activated carbon, in situ chemical oxidation, and in situ chemical reduction. Recent studies suggest that reduction with zerovalent metals, particularly zerovalent zinc, may be particularly effective in TCP remediation. Bioremediation may also be a promising clean-up technique.


1,2,3-Trimethylbenzene
1,2,3-Trimethylbenzene is an organic compound with the chemical formula C6H3(CH3)3. Classified as an aromatic hydrocarbon, it is a flammable colorless liquid. It is nearly insoluble in water but soluble in organic solvents. It occurs naturally in coal tar and petroleum. It is one of the three isomers of trimethylbenzene. It is used in jet fuel, mixed with other hydrocarbons, to prevent the formation of solid particles which might damage the engine.


1,2,3-Trimethylbenzene, Production and uses
Industrially, it is isolated from the C9 aromatic hydrocarbon fraction during petroleum distillation. It is also generated by methylation of toluene and xylenes.


1,2,4,5-Cyclohexanetetrol
1,2,4,5-Cyclohexanetetrol (also named cyclohexane-1,2,4,5-tetrol, 1,2,4,5-tetrahydroxycyclohexane, or para-cyclohexanetetrol) is an organic compound whose molecule can be described as a cyclohexane with four hydroxyl (OH) groups substituted for hydrogen atoms on two non-adjacent pairs of adjacent carbon atoms. Its formula can be written C6H12O4, C6H8(OH)4, or [–(CH(OH)–)2–CH2–]2.


1,2,4,5-Cyclohexanetetrol
There are 7 isomers with this same structural formula, which are among the 43 isomers of cyclohexanetetrol. They are all polyols, more specifically tetrols and cyclitols. Some of them have biologically important roles in some organisms.


1,2,4,5-Cyclohexanetetrol, Isomers and nomenclature
There are 7 different isomers of this compound, that differ in the orientation of the four hydroxyls relative to the mean plane of the ring. They can be denoted by the letter "α" or "β" after each carbon index ("2α","2β","4β", etc. ), to indicate the corresponding side of the plane relative to the 1-hydroxyl; or by listing all the "α" indices, then a slash "/", then the "β" indices (or "0" if the second list is empty).


1,2,4,5-Cyclohexanetetrol, Synthesis
Methods which have been employed for the preparation of 1,2,4,5-cyclohexanetetrols include: reduction or hydrogenation of (1) tri-hydroxycyclohexanones, (2) hydroxylated aromatics, or (3) hydroxylated quinones; the (4) hydrogenolysis of dibromocyclohexanetetrols; the (5) hydration of diepoxycyclohexanes; and the hydroxylation of (6) cyclohexadienes or (7) cyclohexenediols.


1,2,4,5-Cyclohexanetetrol, Synthesis
In 1998, Ahmet Maras and others reported the synthesis of racemic 1,4/2,5-cyclohexanetetrol (the chiral trans-trans para isomer) by hydroxyla-tion of 1,4-cyclohexadiene with stoichiometric amount of hydrogen peroxide (H2O2, 30% in 1-butanol), with selenium dioxide as catalyzer. The yield was 88%, with no trace of the 1,5/2,4 isomer. The racemic 1,4/2,5 isomer is soluble in ethanol, and yields colorless crystals with melting point 194–196 °C. The (+) enantiomer is betitol, a natural product first identified in sugar beets. The pure 1α,2α,4α,5α enantiomer crystallize as a monohydrate in the monoclinic C2 group (a = 10.675 Å, b = 7.3502 Å, c = 5.1968 Å, β = 103.877°)


1,2,4,5-Tetrabromobenzene
1,2,4,5-Tetrabromobenzene is an organobromine compound with the formula C6H2Br4. It is one of three isomers of tetrabromobenzene. The compound is a white solid. 1,2,4,5-Tetrabromobenzene is an important metabolite of the flame retardant hexabromobenzene.


1,2,4,5-Tetrabromobenzene, Preparation
The synthesis of 1,2,4,5-tetrabromobenzene has already been reported in 1865 from benzene and excess bromine in a sealed tube at 150 °C. However, the clearly reduced melting point of about 160 °C indicates impurities in the final product. In his 1885 dissertation, Adolf Scheufelen published the synthesis of a purer sample using iron(III) chloride FeCl3 as a catalyst, isolated as "pretty needles" ("schönen Nadeln").


1,2,4,5-Tetrabromobenzene, Preparation
The synthesis can also be carried out in solution in chloroform or tetrachloromethane and yields 1,2,4,5-tetrabromobenzene in 89% yield. This reaction can also be carried out in a laboratory experiment with excess bromine and iron nails (as starting material for iron (III) bromide FeBr3). The intermediate stage is 1,4-dibromobenzene, which reacts further with excess bromine to give 1,2,4,5-tetrabromobenzene.


1,2,4,5-Tetrabromobenzene, Reactions, Building block for liquid crystals and fluorescent dyes
Owing to its symmetrical structure and reactivity, 1,2,4,5-tetrabromobenzene is a precursor to nematic liquid crystals with crossed mesogens and for columnar (discotic) liquid crystals with an extensive planar, "board-like" tetrabenzoanthracene core.


1,2,4,5-Tetrabromobenzene, Reactions, Building block for liquid crystals and fluorescent dyes
In a one-pot reaction, 1,2,4,5-tetrabromobenzene reacts with 4-hydroxybenzaldehyde, the alkylating agent 1-bromopentane, the Wittig reagent methyltriphenylphosphonium iodide, the base potassium carbonate, the phase transfer catalyst tetrabutylammonium bromide, the Heck reagent palladium(II)acetate and the Heck co-catalyst 1,3-bis(diphenylphosphino)propane (dppp) in dimethylacetamide obtaining directly a symmetrical tetraalkoxylstilbene as E-isomer in 17% yield.


1,2,4,5-Tetrabromobenzene, Reactions, Building block for liquid crystals and fluorescent dyes
Due to their pronounced π-conjugation such compounds could be potentially applied as optical brighteners, OLED materials or liquid crystals.


1,2,4,5-Tetrabromobenzene, Reactions, Building block for liquid crystals and fluorescent dyes
N-alkyl-tetraaminobenzenes are available from 1,2,4,5-tetrabromobenzene in high yields, which can be cyclized with triethyl orthoformate and acids to benzobis(imidazolium) salts (BBI salts) and oxidized with oxygen to form 1,4-benzoquinone diimines.


1,2,4,5-Tetrabromobenzene, Reactions, Building block for liquid crystals and fluorescent dyes
BBI salts are versatile fluorescent dyes with emission wavelengths λem between 329 and 561 nm, pronounced solvatochromism and strong solvent-dependent Stokes shift, which can be used as protein tag for fluorescent labeling of proteins.


1,2,4,5-Tetrabromobenzene, Reactions, Starting material for arynes
From 1,2,4,5-tetrabromobenzene, a 1,4-monoarine can be prepared in-situ with one equivalent of n-butyllithium by bromine abstraction, which reacts immediately with furan to form 6,7-dibromo-1,4-epoxy-1,4-dihydronaphthalene (6,7-dibromonaphthalene-1,4-endoxide) in 70% yield.


1,2,4,5-Tetrabromobenzene, Reactions, Starting material for arynes
When 2,5-dialkylfurans (e.g. 2,5- (di-n-octyl)furan) are used, the dibrominated monoendoxide is formed in 64% yield, from which dibromo-5,8-di-n-octylnaphthalene is formed with zink powder/titanium tetrachloride in 88% yield.


1,2,4,5-Tetrabromobenzene, Reactions, Starting material for arynes
Upon treatment with titanium tetrachloride and zinc dust, the endoxide is deoxygenated yielding 2,3-dibromnaphthalene.


1,2,4,5-Tetrabromobenzene, Reactions, Starting material for arynes
The endoxide reacts with 3-sulfolene in a Diels-Alder reaction upon elimination of sulfur dioxide. The resulting tricyclic adduct converts to 2,3-dibromoanthracene in good yield.


1,2,4,5-Tetrabromobenzene, Reactions, Starting material for arynes
If the dibromene oxide is allowed to react further with furan, in the presence of n-butyllithium or potassium amide or via an intermediate 1,4-aryne the tricyclic 1,4-adduct 1,4:5.8-diepoxy-1,4,5,8-tetrahydroanthracene is formed in 71% yield as a syn-anti-mixture. With sodium amide in ethylene glycol dimethyl ether (DME), however, the dibromene oxide behaves as a 1,3-aryne equivalent and forms with furan a phenanthrene-like tricyclic 1,3-adduct, which can react with furan and sodium amide to a triphenylene derivative (1,3,5-tris-arene).


1,2,4,5-Tetrabromobenzene, Reactions, Starting material for arynes
[ 2+4] cycloadditions with 1,2,4,5-tetrabromobenzene sometimes proceed in very high yields, such as the reaction of a dihalogen-substituted 1,3-diphenyl-isobenzofuran to a tetrahalogenated anthracene derivative (98%), which is converted successively further with 1,3-diphenyl isobenzofuran in 65% yield to a pentacene derivative and furan to a hexacene derivative (67%).


1,2,4,5-Tetrabromobenzene, Reactions, Starting material for arynes
The crosslinking of benzimidazole-modified polymers provides materials with a high absorption capacity for carbon dioxide, which could be suitable for CO2 separation from gas mixtures.


1,2,4,5-Tetrabromobenzene, Safety
1,2,4,5-Tetrabromobenzene is a liver toxic degradation product of the flame retardant hexabromobenzene and was already in 1987 detected in Japan in mother's milk samples.


1,2,4-Butanetriol
1,2,4-Butanetriol is a clear or slightly yellow, odorless, hygroscopic, flammable, viscous liquid. It is an alcohol with three hydrophilic alcoholic hydroxyl groups. It is similar to glycerol and erythritol. It is chiral, with two possible enantiomers.


1,2,4-Butanetriol
1,2,4-Butanetriol is used in the manufacture of butanetriol trinitrate (BTTN), an important military propellant.


1,2,4-Butanetriol
1,2,4-Butanetriol is also used as a precursor for two cholesterol-lowering drugs, Crestor and Zetia, which are derived from D-3,4-dihydroxybutanoic acid, by using 3-hydroxy-gamma-butyrolactone as a chiral synthonIt is used as one of the monomers for manufacture of some polyesters and as a solvent.


1,2,4-Butanetriol
1,2,4-Butanetriol can be prepared synthetically by several different methods such as hydroformylation of glycidol and subsequent reduction of the product, sodium borohydride reduction of esterified malic acid, or catalytic hydrogenation of malic acid. However, of an increasing importance is the biotechnological synthesis using genetically engineered Escherichia coli and Pseudomonas fragi bacteria.


1,2,4-Butanetriol trinitrate
1,2,4-Butanetriol trinitrate (BTTN), also called butanetriol trinitrate, is an important military propellant. It is a colorless to brown explosive liquid.


1,2,4-Butanetriol trinitrate
BTTN is used as a propellant in virtually all single-stage missiles used by the United States, including the Hellfire. It is less volatile, less sensitive to shock, and more thermally stable than nitroglycerine, for which it is a promising replacement.


1,2,4-Butanetriol trinitrate
BTTN as a propellant is often used in a mixture with nitroglycerin. The mixture can be made by co-nitration of butanetriol and glycerol. BTTN is also used as a plasticizer in some nitrocellulose-based propellants.


1,2,4-Butanetriol trinitrate
BTTN is manufactured by nitration of 1,2,4-butanetriol. Biotechnological manufacture of butanetriol is under intensive research.


1,2,4-Triazole
1,2,4-Triazole (as ligand in coordination compounds, Htrz abbreviation is sometimes used) is one of a pair of isomeric chemical compounds with molecular formula C2H3N3, called triazoles, which have a five-membered ring of two carbon atoms and three nitrogen atoms. 1,2,4-Triazole and its derivatives find use in a wide variety of applications.


1,2,4-Triazole, Structure and properties
1,2,4-Triazole is a planar molecule. The C-N and N-N distances fall into a narrow range 136 - 132 picometers, consistent with the aromaticity. Although two tautomers can be envisioned, only one exists practically speaking.


1,2,4-Triazole, Structure and properties
1,2,4-Triazole is amphoteric, being susceptible to both N-protonation and deprotonation in aqueous solution. The pKa of 1,2,4-triazolium (C2N3H4+) is 2.45. The pKa of the neutral molecule is 10.26.


1,2,4-Triazole, Synthesis and occurrence
1,2,4-Triazoles can be prepared using the Einhorn–Brunner reaction or the Pellizzari reaction. Unsubstituted 1,2,4-triazole can be prepared from thiosemicarbazide by acylation with formic acid followed by cyclization of 1-formyl-3-thiosemicarbazide into 1,2,4-triazole-3(5)-thiol; oxidation of the thiol by nitric acid or hydrogen peroxide yields 1,2,4-triazole.


1,2,4-Triazole, Synthesis and occurrence
1,2,4-Triazoles are featured in many kinds of drugs. Notable triazoles include the antifungal drugs fluconazole and itraconazole. Triazolate is a common bridging ligand in coordination chemistry.


1,2,4-Trichlorobenzene
1,2,4-Trichlorobenzene is an organochlorine compound, one of three isomers of trichlorobenzene. It is a derivative of benzene with three chloride substituents. It is a colorless liquid used as a solvent for a variety of compounds and materials.


1,2,4-Trichlorobenzene, Production and uses
Depending on the conditions and additives (e.g., sulfur), it can be the main product from the chlorination of benzene. It is virtually the exclusive product from the chlorination of 1,4-dichlorobenzene. It is also the main product from the dehydrochlorination of hexachlorocyclohexane.


1,2,4-Trichlorobenzene, Production and uses
It is useful as a high-temperature solvent, e.g. for GPC of polyolefines such as PE or PP which are otherwise insoluble.


1,2,4-Trichlorobenzene, Production and uses
Aside from its use as a solvent, this compound is a useful precursor to dye and pesticides.


1,2,4-Trichlorobenzene, Safety
The LD50 (oral, rats) is 756 mg/kg. Animal studies have shown that 1,2,4-trichlorobenzene affects the liver and kidney, and is possibly a teratogen. There is no regulated occupational exposure limit for chemical exposure, but the National Institute for Occupational Safety and Health recommends no greater exposure than 5 ppm, over an 8-hour workday.


1,2,4-Trihydroxyanthraquinone
1,2,4-Trihydroxyanthraquinone, commonly called purpurin, is an anthraquinone. It is a naturally occurring red/yellow dye. It is formally derived from 9,10-anthraquinone by replacement of three hydrogen atoms by hydroxyl (OH) groups.


1,2,4-Trihydroxyanthraquinone
Purpurin is also called verantin, smoke Brown G, hydroxylizaric acid, and C.I. 58205. It is a minor component of the classical lake pigment "madder lake" or Rose Madder.


1,2,4-Trihydroxyanthraquinone, History
Madder root has been used for  dying cloth at least since 1500 BC. Purpurin and alizarin were isolated from the root by Pierre Robiquet and Colin,  two French chemists, in 1826. They were identified as anthracene  derivatives by Gräbe  and Liebermann in 1868. They also synthesized  alizarin from bromoanthraquinone, which, together with the  conversion of alizarin into purpurin published previously by M. F. De Lalande,  provided the first synthetic route to purpurin. The positions of the  OH groups were determined by Bayer and Caro  in 1874–1875.


1,2,4-Trihydroxyanthraquinone, Natural occurrence
Purpurin occurs in the roots of the madder plant (Rubia tinctorum), together with alizarin (1,2-dihydroxyanthraquinone). The root actually contains colorless glycosides of the dyes.


1,2,4-Trihydroxyanthraquinone, Properties
Purpurin is a crystalline solid, that forms orange needles melting at 259 °C (498 °F), but becomes red when dissolved in ethanol, and yellow when dissolved with alkalis in boiling water. It is insoluble in hexane but soluble in chloroform, and can be obtained from chloroform as reddish needles. Unlike alizarin, purpurin is dissolved by boiling in a solution of aluminum sulfate, from which it can be precipitated by acid. This procedure can be used to separate the two dyes.


1,2,4-Trihydroxyanthraquinone, Properties
Like many dihydroxy- and trihydroxyanthraquinones, pupurin has a purgative action, although only 1/20 as effective as 1,2,7-trihydroxyanthraquinone (anthrapurpurin).


1,2,4-Trihydroxyanthraquinone, Uses
Purpurin is a fast dye for cotton printing and forms complexes with various metal ions. However it fades faster than alizarin on exposure to sunlight.


1,2,4-Trihydroxyanthraquinone, Uses
A study published in Nature journal Scientific Reports suggests that the purpurin could replace cobalt in lithium-ion batteries. Eliminating cobalt would mean eliminating a hazardous material, allow batteries to be produced at room temperature, and lower the cost of recycling batteries. Extracting purpurin from farmed madder is a simple task; alternately, the chemical could be synthesized in a lab.


1,2,4-Trimethylbenzene
1,2,4-Trimethylbenzene, also known as pseudocumene, is an organic compound with the chemical formula C6H3(CH3)3. Classified as an aromatic hydrocarbon, it is a flammable colorless liquid with a strong odor. It is nearly insoluble in water but soluble in organic solvents. It occurs naturally in coal tar and petroleum (about 3%). It is one of the three isomers of trimethylbenzene.


1,2,4-Trimethylbenzene, Production
Industrially, it is isolated from the C9 aromatic hydrocarbon fraction during petroleum distillation. Approximately 40% of this fraction is 1,2,4-trimethylbenzene. It is also generated by methylation of toluene and xylenes and the disproportionation of xylene over aluminosilicate catalysts.


1,2,4-Trimethylbenzene, Uses
Pseudocumene is a precursor to mellitic anhydride, from which high performance polymers are made. It is also used as a sterilizing agent and in the making of dyes, perfumes and resins. Another use is as a gasoline additive.


1,2,4-Trimethylbenzene, Uses, Scintillator
1,2,4-Trimethylbenzene dissolved in mineral oil is used as a liquid scintillator in particle physics experiments such as NOνA and Borexino.


1,2,4-Trioxane
1,2,4-Trioxane is one of the isomers of trioxane. It has the molecular formula C3H6O3 and consists of a six membered ring with three carbon atoms and three oxygen atoms. The two adjacent oxygen atoms form a peroxide functional group and the other forms an ether functional group. It is like a cyclic acetal but with one of the oxygen atoms in the acetal group being replaced by a peroxide group.


1,2,4-Trioxane
1,2,4-Trioxane itself has not been isolated or characterized, but rather only studied computationally. However, it constitutes an important structural element of some more complex organic compounds. The natural compound artemisinin, isolated from the sweet wormwood plant (Artemisia annua), and some semi-synthetic derivatives are important antimalarial drugs containing the 1,2,4-trioxane ring. Completely synthetic analogs containing the 1,2,4-trioxane ring are important potential improvements over the naturally derived artemisinins. The peroxide group in the 1,2,4-trioxane core of artemisinin is cleaved in the presence of the malaria parasite leading to reactive oxygen radicals that are damaging to the parasite.


1,2,6-Hexanetriol
1,2,6-Hexanetriol is a trivalent alcohol with two primary and one secondary hydroxy group. It is similar to glycerol in many respects and is used as a substitute for glycerol in many applications due to its more advantageous properties, such as higher thermal stability and lower hygroscopicity.


1,2,6-Hexanetriol, Production
Racemic 1,2,6-hexanetriol is obtained by catalytic hydrogenation of 2-hydroxyadipaldehyde (2-hydroxyhexane-1,6-dial) which is in turn produced by the acid hydrolysis of acrolein dimer (3,4-dihydro-2-formyl-2H-pyran) in dilute aqueous solution.


1,2,6-Hexanetriol, Production
Despite high product yields, a lightly colored product is obtained on this direct route and the hydrogenation catalyst is rapidly poisoned under the high aldehyde concentrations. For industrial production, it is therefore suitable to carry out the reaction in acidic alcoholic solutions, whereby the solvent alcohol quickly adds to the activated double bond to form 2-formyl-6-alkoxytetrahydropyran (THP) and then reacts with the formyl group to form the corresponding hemiacetal. Water is added to the reaction mixture to hydrolyse the acetal groups and Raney nickel is added as a hydrogenation catalyst. The hydrogenation under 20 atm hydrogen at 140 °C is completed after approx. 1.5 h and, after work-up, yields pure 1,2,6-hexanetriol in a yield >95 %.


1,2,6-Hexanetriol, Production
Recently, several authors have described the synthesis of 1,2,6-hexanetriol from the easily accessible platform chemical hydroxymethylfurfural (HMF), which can be produced from "carbon neutral" (i.e. renewable) raw materials such as pentoses, hexoses, and other carbohydrates. In the first hydrogenation step from HMF to tetrahydrofuran-dimethanol, Raney nickel again shows the highest catalyst activity. Further hydrogenation, even with expensive rhodium-rhenium catalysts, leads only to modest selectivities and unsatisfactory yields.


1,2,6-Hexanetriol, Properties
1,2,6-Hexanetriol is a clear, odourless, viscous, high-boiling and hygroscopic liquid, which is miscible with water and polar organic solvents but immiscible with non-polar solvents such as benzene, diethyl ether or heptane. The compound is similar in its properties to the simplest triol glycerol, but it is much more viscous at lower density and only about half as hygroscopic as glycerol. Because of its lower polarity and higher molecular volume, 1,2,6-hexanetriol often forms more stable mixtures or emulsions, especially with non-polar components, and is therefore also a useful plasticizer.


1,2,6-Hexanetriol, Use
1,2,6-Hexanetriol is used as a solvent, for raising the viscosity of liquid and semi-solid cosmetic and pharmaceutical preparations due to its low toxicity and good compatibility, and as a humectant due to its hygroscopicity. 1,2,6-hexanetriol improves the effectiveness of the active ingredients as an adjuvant in crop protection formulations. In inks and paints it stabilizes the dispersion of pigments. Derivatives of 1,2,6-hexanetriol are also used in hydraulic fluids and as corrosion inhibitors. As a trifunctional molecule, 1,2,6-hexanetriol acts as a polyol in polyurethanes and as a crosslinker in polyesters and alkyd resins.


1,2,6-Hexanetriol, Use
Esters of 1,2,6-hexanetriol with longer-chain carboxylic acids are useful plasticizers for PVC and cellulose acetate, as well as for rubber polymers such as nitrile rubber (NBR) and neoprene., 1,2,6-hexanetriol is used as a monomer for the synthesis of POE III type polyorthoesters, which are characterized by an ointment-like consistency due to the high flexibility of the triol and have been tested as active ingredient depot materials for ophthalmic applications.


1,2,6-Trigalloyl glucose
1,2,6-Trigalloyl glucose is a gallotannin found in cell cultures of Cornus officinalis.


1,2-Benzoquinone
1,2-Benzoquinone, also called ortho-benzoquinone, is an organic compound with formula C6H4O2. It is one of the two isomers of quinone, the other being 1,4-benzoquinone. It is a red volatile solid that is soluble in water and ethyl ether. It is rarely encountered because of its instability, but it is of fundamental interest as the parent compound of many derivatives which are known.


1,2-Benzoquinone, Structure
The molecule has C2v symmetry. X -ray crystallography shows that the double bonds are localized, with alternatingly long and short C-C distances within the ring. The C=O distances of 1.21 Å are characteristic of ketones.


1,2-Benzoquinone, Preparation and occurrence
1,2-Benzoquinone is produced on oxidation of catechol exposed to air in aqueous solution or by ortho oxidation of a phenol.


1,2-Benzoquinone, Preparation and occurrence
A strain of the bacterium Pseudomonas mendocina metabolises benzoic acid, yielding 1,2-benzoquinone via catechol.


1,2-Bis(dichlorophosphino)benzene
1,2-Bis(dichlorophosphino)benzene is an organophosphorus compound with the formula C6H4(PCl2)2. A viscous colorless liquid, it is a precursor to chelating diphosphines of the type C6H4(PR2)2. It is prepared from 1,2-dibromobenzene by sequential lithiation followed by treatment with (Et2N)2PCl (Et = ethyl), which affords C6H4[P(NEt2)2]2. This species is finally cleaved with hydrogen chloride:


1,2-Bis(dichlorophosphino)ethane
1,2-Bis(dichlorophosphino)ethane is an organophosphorus compound with the formula (CH2PCl2)2. A colorless liquid, it is a precursor to chelating diphosphines.


1,2-Bis(dichlorophosphino)ethane, Synthesis and reactions
It is prepared by the reaction of ethylene, white phosphorus, and phosphorus trichloride:


1,2-Bis(dichlorophosphino)ethane, Synthesis and reactions
The compound reacts with Grignard reagents and secondary amines to give chelating ligands. An often practiced use of this compound is the synthesis of 1,2-bis(dimethylphosphino)ethane.


1,2-Bis(dicyanomethylene)squarate
1,2-Bis(dicyanomethylene)squarate is a divalent anion with chemical formula C10N4O2−2 or ((N≡C−)2C=)2(C4O2)2−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the squarate oxocarbon anion C4O2−4 through the replacement of two adjacent oxygen atoms by dicyanomethylene groups =C(−C≡N)2.


1,2-Bis(dicyanomethylene)squarate
The anion can be obtained by reacting squaric acid with n-butanol to obtain the diester 1,2-dibutyl squarate (an oily orange liquid) and treating the latter with metallic sodium and malononitrile (N≡C−)2CH2 to give the  trihydrated disodium salt 2Na+·C10N4O2−2·3H2O, a yellow water-soluble solid. The hydrated salt loses the water below 100 °C, but the resulting anhydrous salt is stable up to 400 °C. Reaction of the sodium salt with the  chlorides of other cations in ethanol affords the following salts:


1,2-Bis(dicyanomethylene)squarate
Nuclear magnetic resonance shows that the aromatic character of the squarate core is retained.


1,2-Bis(diisopropylphosphino)ethane
1,2-Bis(diisopropylphosphino)ethane (dippe) is a commonly used bidentate ligand in coordination chemistry. This compound is similar to the ligand 1,2-bis(diphenylphosphino)ethane (dppe),  with the substitution of isopropyl groups for phenyl groups.


1,2-Bis(dimethylarsino)benzene
1,2-Bis(dimethylarsino)benzene (diars) is the organoarsenic compound with the formula C6H4(As(CH3)2)2. The molecule consists of two dimethylarsino groups attached to adjacent carbon centers of a benzene ring. It is a chelating ligand in coordination chemistry. This colourless oil is commonly abbreviated "diars."


1,2-Bis(dimethylarsino)benzene, Coordination chemistry
Related, but non-chelating organoarsenic ligands include triphenylarsine and trimethylarsine. Work on diars preceded the development of the chelating diphosphine ligands such as dppe, which are now prevalent in homogeneous catalysis.


1,2-Bis(dimethylarsino)benzene, Coordination chemistry
Diars is a bidentate ligand used in coordination chemistry. It was first described in 1939, but was popularized by R. S. Nyholm for its ability to stabilize metal complexes with unusual oxidation states and coordination numbers, e.g. TiCl4(diars)2. High coordination numbers arise because diars is fairly compact and the As-M bonds are long, which relieves crowding at the metal center. In terms of stabilizing unusual oxidation states, diars stabilizes Ni(III), as in [NiCl2(diars)2]Cl.


1,2-Bis(dimethylarsino)benzene, Coordination chemistry
Of historical interest is the supposedly diamagnetic [Ni(diars)3](ClO4)2, obtained by heating nickel perchlorate with diars. Octahedral d8 complexes characteristically have triplet ground states, so the diamagnetism of this complex was puzzling. Later by X-ray crystallography, the complex was shown to be pentacoordinate with the formula [Ni(triars)(diars)](ClO4)2, where triars is the tridentate ligand [C6H4As(CH3)2]2As(CH3), arising from the elimination of trimethylarsine.


1,2-Bis(dimethylarsino)benzene, Preparation and handling
Diars is prepared by the reaction of ortho-dichlorobenzene and sodium dimethylarsenide:


1,2-Bis(dimethylarsino)benzene, Preparation and handling
It is a colorless liquid. Oxygen converts diars to the dioxide, C6H4(As(CH3)2O)2.


1,2-Bis(dimethylphosphino)ethane
1,2-Bis(dimethylphosphino)ethane (dmpe) is a diphosphine ligand in coordination chemistry. It is a colorless, air-sensitive liquid that is soluble in organic solvents. With the formula (CH2PMe2)2 is used as a compact strongly basic spectator ligand (Me = methyl),  Representative complexes include V(dmpe)2(BH4)2, Mn(dmpe)2(AlH4)2, Tc(dmpe)2(CO)2Cl, and Ni(dmpe)Cl2.


1,2-Bis(dimethylphosphino)ethane, Synthesis
It is synthesised by the reaction of methylmagnesium iodide with 1,2-bis(dichlorophosphino)ethane:


1,2-Bis(dimethylphosphino)ethane, Synthesis
Alternatively it can be generated by alkylation of sodium dimethylphosphide.


1,2-Bis(dimethylphosphino)ethane, Synthesis
The synthesis of dmpe from thiophosphoryl chloride has led to serious accidents and has been abandoned.


1,2-Bis(dimethylphosphino)ethane, Related ligands
Tetramethylethylenediamine is the diamine analogue of the diphosphine dmpe. Bis(dicyclohexylphosphino)ethane is an analog that is bulkier, and also has the advantage of being a solid.


1,2-Bis(diphenylphosphino)benzene
1,2-Bis(diphenylphosphino)benzene (dppbz) is an organophosphorus compound with the formula C6H4(PPh2)2 (Ph = C6H5). Classified as a diphosphine ligand, it is a common bidentate ligand in coordination chemistry. It is a white, air-stable solid. As a chelating ligand, dppbz is very similar to 1,2-bis(diphenylphosphino)ethylene.


1,2-Bis(diphenylphosphino)ethane
1,2-Bis(diphenylphosphino)ethane (dppe) is an organophosphorus compound with the formula (Ph2PCH2)2 (Ph = phenyl). It is a commonly used bidentate ligand in coordination chemistry. It is a white solid that is soluble in organic solvents.


1,2-Bis(diphenylphosphino)ethane, Preparation
The preparation of dppe is by the alkylation of NaPPh2:


1,2-Bis(diphenylphosphino)ethane, Preparation
NaP(C6H5)2, which is readily air-oxidized, is treated with 1,2-dichloroethane (ClCH2CH2Cl) to give dppe:


1,2-Bis(diphenylphosphino)ethane, Reactions
The reduction of dppe by lithium to give PhHP(CH2)2PHPh has been reported.


1,2-Bis(diphenylphosphino)ethane, Reactions
Treatment of dppe with conventional oxidants such as hydrogen peroxide (H2O2), aqueous bromine (Br2), etc., produces dppeO in low yield (e.g., 13%) as a result of non-selective oxidation. Selective mono-oxidation of dppe can be achieved by reaction with PhCH2Br to give dppeO.


1,2-Bis(diphenylphosphino)ethane, Coordination complexes
Many coordination complexes of dppe are known, and some are used as homogeneous catalysts. Dppe is almost invariably chelating, although there are examples of monodentate (e.g., W(CO)5(dppe)) and of bridging behavior. The natural bite angle is 86°.


1,2-Bis(diphenylphosphino)ethylene
cis-1,2-Bis(diphenylphosphino)ethylene (dppv) is an organophosphorus compound with the formula C2H2(PPh2)2 (Ph = C6H5). Both the cis and trans isomers are known, but the cis isomer is of primary interest. Classified as a diphosphine ligand, it is a bidentate ligand in coordination chemistry. For example it gives rise to the complex Ni(dppv)2 and the coordination polymer [Ni(dppv)]n.   As a chelating ligand, dppv is very similar to 1,2-bis(diphenylphosphino)benzene.


1,2-Bis(diphenylphosphino)ethylene
The diphosphine is prepared by reaction of lithium diphenylphosphide with cis-dichloroethylene.


1,2-Butadiene
1,2-Butadiene is the organic compound with the formula CH2=C=CHCH3. It is an isomer of 1,3-butadiene, a common monomer used to make synthetic rubber. It is a colorless flammable gas, one of the simplest substituted allenes.


1,2-Butadiene, Production
The C4-fraction obtained by cracking and separated by distillation consists of many compounds, predominantly (75%) 1,3-butadiene, isobutene, 1-butene. 1,2-Butadiene comprises less than 1% or this mixture. It is partially purified by extraction with N-methylpyrrolidone. US product is 5,000 -25,000 tons.


1,2-Butanediol
1,2-Butanediol is the organic compound with the formula HOCH2(HO)CHCH2CH3. It is classified as a vic-diol (glycol). It is chiral, although typically it is encountered as the racemic mixture. It is a colorless liquid.


1,2-Butanediol, Preparation
1,2-Butanediol is a byproduct of the production of 1,4-butanediol from butadiene. It is also a byproduct of the catalytic hydrocracking of starches and sugars such as sorbitol to ethylene glycol and propylene glycol.


1,2-Butanediol, Preparation
This diol was first described by Charles-Adolphe Wurtz in 1859.


1,2-Butanediol, Applications
It has been patented for the production of polyester resins and plasticizers. It is a potential feedstock for the industrial production of α-ketobutyric acid, a precursor to some amino acids.


1,2-Butylene carbonate
1,2-Butylene carbonate is an organic compound with formula C5H8O3, or (H5C2)(C2H3)(CO3). It is a double ester with the carbonate functional group bonded to both free ends of the 1,2-butylene group. It is also a heterocyclic compound with a five-membered ring, and can be seen as a derivative of dioxolane, specifically 4-ethyl-1,3-dioxolan-2-one.


1,2-Butylene carbonate
1,2-Butylene carbonate is a polar aprotic solvent, which has been considered for electric battery applications (as a cheaper alternative to ionic liquids) and many other uses.


1,2-Cyclohexane dicarboxylic acid diisononyl ester
1,2-Cyclohexane dicarboxylic acid diisononyl ester (DINCH) is a mixture of organic compounds with the formula C6H10(CO2C9H19)2. DINCH is colorless oil. It is used as a plasticizer for the manufacture of flexible plastic articles in sensitive application areas such as toys, medical devices, and food packaging. It is of interest as an alternative for phthalate plasticizers, which are implicated as endocrine disruptors.


1,2-Cyclohexane dicarboxylic acid diisononyl ester, Production
DINCH can be produced by the catalytic hydrogenation of diisononyl phthalate. Alternatively it can be prepared by Diels-Alder reaction of a diisononyl maleate with 1,3-butadiene followed by hydrogenation. In the case of the catalytic hydrogenation the aromatic, planar part of the diisononyl phthalate is transformed to a cyclohexane ring. Commercial DINCH consists of 90% of the cis and 10% of the trans (chiral) isomers.


1,2-Cyclohexane dicarboxylic acid diisononyl ester, Use
In February 2009, Mattel and Learning Curve confirmed that they were substituting phthalates with Hexamoll® DINCH and citrate-based plasticizers.


1,2-Cyclohexane dicarboxylic acid diisononyl ester, Regulatory approval, Food contact
In the European Union the European Food Safety Authority approved DINCH for a wide variety of food contact applications in October 2006. In 2007 DINCH has been added to Annex III of the "Directive 2002/72/EC relating to plastic materials and articles intended to come into contact with food". The EU Directive 2002/72 has meanwhile been superseded by Regulation (EU) No 10/2011. Hexamoll® DINCH is listed in Annex I of Regulation (EU) No 10/2011 by as Food Conctact Material (FCM) 775 by its chemical name, i.e. as 1,2-cyclohexanedicarboxylic acid, diisononylester.


1,2-Cyclohexane dicarboxylic acid diisononyl ester, Regulatory approval, Toys
In the European Union 1,2-cyclohexane dicarboxylic acid diisononyl ester was not listed in directive 2005/84/EC. These restrictions for certain phthalates are now transferred into Annex XVII, 51 and 52 of Regulation (EC) No 1907/2006 which ban the use of certain phthalates in toys and childcare articles and thus DINCH can be used safely in toys and childcare articles.


1,2-Cyclohexane dicarboxylic acid diisononyl ester, Possible health effects
A research group from Harvard and CDC found suggestive negative associations between urinary MHiNCH, the monoester of DINCH, a minor urinary metabolite. . Their research at a fertility clinic showed that women who had been exposed to DINCH had lower, but statistically not significant estradiol hormone levels and fewer, again not statistically significant number of oocytes in their ovaries. However, urinary MHiNCH concentrations were unrelated to mature oocyte yield and endometrial wall thickness. The results are inconclusive and therefore, the authors suggest that more epidemiological studies would be needed for clarification.


1,2-Cyclohexane dicarboxylic acid diisononyl ester, Possible health effects
The Swedish IVL Environmental Research Institute and researches from the Department of Environmental Science and Analytical Chemistry of Stockholm University recommend that "children's exposure to DINCH should be investigated in more detail and exposure to the general population should be closely monitored" as DINCH is used as an alternative plasticizer in e.g. children's toys.


1,2-Cyclohexane dicarboxylic acid diisononyl ester, Possible health effects
The Chronic Hazard Advisory Panel of the U.S. Consumer Product Safety Commission "strongly encourages the appropriate U.S. agencies to obtain the necessary toxicological and exposure data to assess any potential risk from DINX" because of "lack of publicly available information".


1,2-Cyclohexane dicarboxylic acid diisononyl ester, Possible health effects
A French group from the University of Clermont-Ferrand noted that clinical data and data regarding the migration from Medical Devices would be rare. The Project was funded by the French Agency for the Safety of Health Products (ANSM). It remains unclear why this Research Group was not able to identify the published human biomonitoring data which give a perfect overview on population exposure of alternative plasticizers (e.g. DINCH/DINX) and their metabolites.


1,2-Cyclohexane dicarboxylic acid diisononyl ester, Possible health effects
A report by the Danish Ministry of the Environment states that the available data for DINCH do not indicate a need for further investigations. Further, the conclusion is that 3 of the evaluated plasticizers, namely the substances COMGHA, DEHT and DINCH may be seen as the most promising alternatives, as these substances have an extended data set (complying to Annex X data requirements, i.e. a two-generation reproduction study) without indicating specific concern for reproductive toxicity or endocrine activity. Toxicogenomic screening showed that 648 genes were significantly changed after 48 hours exposure to DINCH suggesting that "DINCH is biologically active".


1,2-Cyclohexanedione
1,2-Cyclohexanedione is an organic compound with the formula (CH2)4(CO)2. It is one of three isomeric cyclohexanediones. It is a colorless compound that is soluble in a variety of organic solvents. It can be prepared by oxidation of cyclohexanone by selenium dioxide. The enol is about 1 kcal/mol more stable than the diketo form.


1,2-Cyclohexanedione
Numerous diimine and dioxime ligands have been prepared from this diketone. It condenses with 1,2-diamines to give diaza heterocycles.


1,2-Cyclopentanedione
1,2-Cyclopentanedione is the organic compound with the formula (CH2)3(CO)2. It is one of two isomeric cyclopentanediones, the other being 1,3-cyclopentanedione. It was first prepared by base-induced condensation of diethylglutarate with diethyloxalate, followed by hydrolysis of the resulting diketodiester followed by decarboxylation. The enol is predicted to be about 1-3 kcal/mol more stable than the diketo form. The enol structure has been confirmed by X-ray crystallography.


1,2-Cyclopentanedione
Structurally related to 1,2-cyclopentanedione is 2-hydroxy-3-methyl-2-cyclopenten-1-one is a flavor additive, also called cyclotene.


1,2-Diaminocyclohexane
1,2-Diaminocyclohexane is an organic compound with the formula (CH2)4(CHNH2)2. It is a mixture of three stereoisomers: cis-1,2-diaminocyclohexane and both enantiomers of trans-1,2-diaminocyclohexane. The mixture is a colorless, corrosive liquid, although older samples can appear yellow. It is often called DCH-99 and also DACH.


1,2-Diaminocyclohexane, Manufacture
The product is available commercially, manufactured by the hydrogenation of o-phenylenediamine. The two trans enantiomers can be resolved by conversion to diastereomeric salts of various chiral acids.


1,2-Diaminocyclohexane, Uses
The product is an epoxy curing agent for use in Coatings, Adhesives, Sealants and Elastomers - CASE. It is particularly useful in epoxy flooring. It may also be reacted with diethyl maleate utilizing the Michael reaction to produce a polyaspartic compound of CAS number 481040-92-0. It may also be used in lubricants. The product is also advertised as being useful as a chelating agent in a variety of applications including oil production. It also is used in downfield oil and gas wells where there is an acidic stream to prevent corrosion to the bore piles.


1,2-Diaminopropane
1,2-Diaminopropane (propane-1,2-diamine) is organic compound with the formula CH3CH(NH2)CH2NH2. A colorless liquid, it is the simplest chiral diamine. It is used as a bidentate ligand in coordination chemistry.


1,2-Diaminopropane, Preparation
Industrially, this compound is synthesized by the ammonolysis of 1,2-dichloropropane:


1,2-Diaminopropane, Preparation
This preparation allows for the use of waste chloro-organic compounds to form useful amines using inexpensive and readily available ammonia.


1,2-Diaminopropane, Preparation
The racemic mixture of this chiral compound may be separated into enantiomers by conversion into the diastereomeric tartaric acid ammonium salt. After purification of the diastereomer, the diamine can be regenerated by treatment of the ammonium salt with sodium hydroxide. Alternate reagents for chiral resolution include N-p-toluenesulfonylaspartic acid, N-benzenesulfonylaspartic acid, or N-benzoylglutamic acid.


1,2-Diaminopropane, Uses, Metal deactivator
1,2-Diaminopropane is used in the synthesis of N,N′-disalicylidene-1,2-propanediamine, a salen-type ligand, usually abbreviated as salpn, that is used as a metal deactivating additive in motor oils.


1,2-Diazepine
1,2-Diazepine is a seven-membered heterocyclic compound with two nitrogen atoms (e.g., in ring positions 1 and 2) and three double bonds.


1,2-Dibromo-3-chloropropane
1,2-Dibromo-3-chloropropane, (dibromochloropropane) better known as DBCP, is the organic compound with the formula BrCH(CH2Br)(CH2Cl). It is a dense colorless liquid although commercial samples often appear amber or even brown. It is the active ingredient in the nematicide Nemagon, also known as Fumazone.


1,2-Dibromo-3-chloropropane
It is a soil fumigant formerly used in American agriculture. In mammals it causes male sterility at high levels of exposure. After discovery of its deleterious health effects on humans, the compound was banned from use in 1979 by the United States Environmental Protection Agency (EPA). The continuing presence of the chemical as a contaminant in ground water remains a problem for many communities for years after end of use.


1,2-Dibromo-3-chloropropane, Examples of persistence
DBCP residues have persisted in contaminated soil and groundwater long after applications have ceased. For example, in agricultural areas around Turlock in the Central Valley of California, DBCP was applied to crops in the 1970s. As late as 1989, DBCP persistence was reported in groundwater that was previously used for beneficial purposes, and numerous nearby wells had to be shut down at that time.


1,2-Dibromo-3-chloropropane, Lawsuits
Workers at the Dow Chemical plant producing DBCP were made sterile by exposure to DBCP. These male reproductive effects were consistent with animal experiments showing that DBCP sterilizes rabbits. One contract worker at the production plant successfully sued the company. Most workers remained with the company and in a company sponsored medical program until the facility was sold in 1987. At that time, some of the workers did file suit against the company. However, the suit was denied due to statute of limitations issues.


1,2-Dibromo-3-chloropropane, Lawsuits
Most domestic uses of the chemical were banned in 1977. Amid growing concerns over DBCP's effects on male workers, Dow ceased production and reclaimed DBCP that had been shipped to its users.


1,2-Dibromo-3-chloropropane, Lawsuits
However, despite warnings from Dow about its health effects, the Dole Food Company, which was using the chemical on its banana plantations in Latin America, threatened to sue Dow if it stopped DBCP shipments. Dow then shipped half a million gallons of DBCP to Dole, much of it reclaimed from other users. Plantation workers who became sterile or were stricken with other maladies subsequently sued Dow and Dole in Nicaraguan courts, alleging that their ailments were caused by DBCP exposure.


1,2-Dibromo-3-chloropropane, Lawsuits
Under a special law that was passed specifically for DBCP litigation, the Nicaraguan courts ruled in favor of the plaintiffs and awarded them over US$600 million in damages.


1,2-Dibromo-3-chloropropane, Lawsuits
When plaintiff lawyers tried to enforce one of those judgments in the United States, the U.S. District Court in Florida held that "the credible and unrefuted medical testimony in this case is that it is factually impossible for what is represented in the Judgment to have occurred," and that due process "do[es] not permit awarding damages in the face of clear scientific evidence of the absence of causation," or, as in this case, "with proof that [the defendants] are not at fault."


1,2-Dibromo-3-chloropropane, Lawsuits
A group of workers then filed lawsuits in the United States, and on November 5, 2007, a Los Angeles jury awarded them US$3.2 million. On July 15, 2010, that judgment was thrown out after the Court presiding over the case found that the claims were part of "a massive fraud perpetrated on the court". On April 23, 2009, a Los Angeles judge also threw out two similar cases against Dole and Dow Chemical due to fraud and extortion by lawyers in Nicaragua recruiting fraudulent plaintiffs to make claims against the company. The ruling casts doubt on US$2 billion in judgments in similar lawsuits.


1,2-Dibromo-3-chloropropane, Lawsuits
Workers in Côte d'Ivoire, using the Alien Tort Claims Act, and claiming sterility, crimes against humanity, and genocide, sued (in Abagninin v. AMVAC Chemical Corp. [ No. 07 -56326]), these manufacturers of DBCP: Amvac Chemical, Dow Chemical, Shell Oil Company, as well as Dole Food Company, who used it on overseas crops, but never used it in Côte d'Ivoire.


1,2-Dibromo-3-chloropropane, Lawsuits
The United States Court of Appeals for the Ninth Circuit ruled against the workers in September 2008, stating that the plaintiffs did not show that the defendants had "specific intent" to intend harm against the workers and the citizens of the country. To be found guilty of genocide the defendant must have knowingly set out to commit the offense.


1,2-Dibromo-3-chloropropane, Safety
DBCP causes a dramatic decrease in male fertility, ranging from oligospermia (low sperm count) to azoospermia (lack of sperm).


1,2-Dibromobenzene
1,2-Dibromobenzene is an organobromine compound with the formula C6H4Br2. It is one of three isomers, the others being 1,3- and 1,4-dibromobenzene. It is a colorless liquid, although impure samples appear yellowish. The compound is a precursor to many 1,2-disubstituted derivatives of benzene. For example, it is a precursor to 1,2-dicyanobenzene and dithioethers.


1,2-Dibromoethane
1,2-Dibromoethane, also known as ethylene dibromide (EDB), is an organobromine compound with the chemical formula C2H4Br2. Although trace amounts occur naturally in the ocean, where it is formed probably by algae and kelp, it is mainly synthetic. It is a dense colorless liquid with a faint sweet odor, detectable at 10 ppm, is a widely used and sometimes-controversial fumigant. The combustion of 1,2-dibromoethane produces hydrogen bromide gas that is significantly corrosive.


1,2-Dibromoethane, Preparation and use
It is produced by the reaction of ethylene gas with bromine, in a classic halogen addition reaction:


1,2-Dibromoethane, Preparation and use
Historically, 1,2-dibromoethane was used as a component in anti-knock additives in leaded fuels. It reacts with lead residues to generate volatile lead bromides, thereby preventing fouling of the engine with lead deposits.


1,2-Dibromoethane, Preparation and use, Pesticide
It has been used as a pesticide in soil and on various crops. The applications were initiated after the forced retirement of 1,2-dibromo-3-chloropropane (DBCP). Most of these uses have been stopped in the U.S. It continues to be used as a fumigant for treatment of logs for termites and beetles, for control of moths in beehives.


1,2-Dibromoethane, Preparation and use, Reagent
1,2-Dibromoethane has wider applications in the preparation of other organic compounds including those carrying modified diazocine rings and vinyl bromide that is a precursor to some fire retardants.


1,2-Dibromoethane, Preparation and use, Reagent
In organic synthesis, 1,2-dibromoethane is used as a source of bromine to brominate carbanions and to activate magnesium for certain Grignard reagents. In the latter process, 1,2-dibromoethane reacts with magnesium, producing ethene and magnesium bromide, and exposes a freshly etched portion of magnesium to the substrate.


1,2-Dibromoethane, Health effects
1,2-Dibromoethane causes changes in the metabolism and severe destruction of living tissues. The known empirical LD50 values for 1,2-dibromoethane are 140 mg kg−1 (oral, rat), and 300.0 mg kg−1 (dermal, rabbit). 1,2-Dibromoethane is a known carcinogen, with pre-1977 exposure levels ranking it as the most carcinogenic substance on the HERP Index.


1,2-Dibromoethane, Health effects
The effects on people of breathing high levels are not known, but animal studies with short-term exposures to high levels caused depression and collapse, indicating effects on the brain. Changes in the brain and behavior were also seen in young rats whose male parents had breathed 1,2-dibromoethane, and birth defects were observed in the young of animals that were exposed while pregnant. 1,2-Dibromoethane is not known to cause birth defects in humans. Swallowing has caused death at 40ml doses.


1,2-Dibromoethylene
1,2-Dibromoethylene, also known as 1,2-dibromoethene and acetylene dibromide, is a dihalogenated unsaturated compound with one bromine on each of the two carbon atoms. There are two isomers of this compound, cis and trans. Both isomers are colorless liquids.


1,2-Dibromoethylene, Synthesis
1,2-dibromoethylene can be synthesized by halogenation of acetylene C2H2 with bromine Br2. In order to prevent the formation tetrahalogenated compounds, acetylene is used in excess, with Br2 as the limiting reagent.


1,2-Dibromoethylene, Synthesis
Alternately, halogenation of this kind could also be achieved through the use of two equivalents of N-bromosuccinimide and lithium bromide (LiBr). N-Bromosuccinimide provides Br+ as an electrophile, which is followed by Br− from LiBr.


1,2-Dibromopropane
1,2-Dibromopropane, also known as propylene dibromide, is an organic compound with the formula CH3CHBrCH2Br. It is the simplest chiral hydrocarbon containing two bromine atoms:


1,2-Dichloro-1,1,2-trifluoroethane
1,2-Dichloro-1,1,2-trifluoroethane is a volatile liquid chlorofluoroalkane composed of carbon, hydrogen, chlorine and fluorine, and with structural formula CClF2CHClF. It is also known as a refrigerant with the designation R-123a.


1,2-Dichloro-1,1,2-trifluoroethane, Properties
The critical temperature of R-123a is 461.6 K (188.5 °C; 371.2 °F). The rotation of the molecule appears to be hindered by the present of chlorine on each carbon atom, but is eased at higher temperatures.


1,2-Dichloro-1,1,2-trifluoroethane, Use
Although not deliberately used, R-123a is a significant impurity in its isomer, the widely used 2,2-dichloro-1,1,1-trifluoroethane (R-123).


1,2-Dichloro-2-nitrosopropane
1,2-Dichloro-2-nitrosopropane is a chlorinated nitrosoalkane. It's a deep blue liquid with powerful lachrymatory effects.