2,5-Furandicarboxylic acid, Properties and conversions
Newer methods have been described by Janda et al., who introduced the synthesis of 2,5-furandicarboxylic dichloride, by the reaction of FDCA with thionyl chloride The synthesis of diethyl ester and dimethyl ester as well as the amidation as well as several other modifications have been reported. The versatility of FDCA is also seen in the number of derivatives available via relatively simple chemical transformations. Selective reduction can lead to partially hydrogenated products, such as 2,5 dihydroxymethylfuran, and fully hydrogenated materials, such as 2,5 bis(hydroxymethyl)tetrahydrofuran.


2,5-Furandicarboxylic acid, Applications
The most important group of FDCA conversions is undoubtedly the polymerization. The potential applications of furan-based building blocks for polymer applications has been extensively reviewed by Gandini. A notable example is polyethylene 2,5-furandicarboxylate, but also other polyesters and various polyamides and polyurethanes have been described in literature. Amongst others like Dupont and Corbion, the company Avantium claims to have developed a cost-effective route to produce FDCA and the derived polyesters. FDCA has also been applied in pharmacology. It was demonstrated that its diethyl ester had a strong anaesthetic action similar to cocaine.


2,5-Furandicarboxylic acid, Applications
Dicalcium 2,5-furandicarboxylate was shown to inhibit the growth of Bacillus megatorium. Screening studies on FDCA-derived anilides showed their important anti-bacterial action. The diacid itself is a strong complexing agent, chelating such ions as: Ca2+, Cu2+ and Pb2+; it is utilized in medicine to remove kidney stones. HMF is metabolized via FDCA in mammals including humans. A very diluted solution of FDCA in tetrahydrofuran is utilized for preparing artificial veins for transplantation. At the beginning of this chapter, it was mentioned that FDCA is a chemically stable compound.


2,5-Furandicarboxylic acid, Applications
This property has been well benefited in industry – FDCA as most of polycarboxylic acids can be an ingredient of fire foams. Such foams help to extinguish fires in a short time caused by polar and non-polar solvents. FDCA has a large potential as a replacement for terephthalic acid, a widely used component in various polyesters, such as polyethylene terephthalate (PET) and polybutyleneterephthalate (PBT). The versatility of FDCA is also seen in the number of derivatives available via relatively simple chemical transformations. Selective reduction can lead to partially hydrogenated products, such as 2,5-dihydroxymethylfuran, and fully hydrogenated materials, such as 2,5-bis(hydroxymethyl)tetrahydrofuran.


2,5-Furandicarboxylic acid, Applications
Both of these latter materials can serve as alcohol components in the production of new polyester, and their combination with FDCA would lead to a new family of completely biomass-derived products. Extension of these concepts to the production of new nylons, either through reaction of FDCA with diamines, or through the conversion of FDCA to 2,5-bis(aminomethyl)tetrahydrofuran. FDCA can also serve as a starting material for the production of succinic acid, whose utility is elsewhere.


2,5-Furandicarboxylic acid, Technical barriers
The primary technical barrier in the production and use of FDCA is the development of an effective and selective dehydration process from sugars. The control of sugar dehydration could be a very powerful technology, leading to a wide range of additional, inexpensive building blocks, but it is not yet well understood. Currently, dehydration processes using hydroxymethylfurfural (HMF) as intermediate are generally non-selective, unless, immediately upon their formation, the unstable intermediate products can be transformed into more stable materials such as methoxymethylfurfural (MMF). Necessary R&D will include development of selective dehydration systems and catalysts. FDCA formation will require development of cost-effective and industrially viable oxidation technology that can operate in concert with the necessary dehydration processes.


2,5-Xylidine
2,5-Xylidine is an organic compound with the formula C6H3(CH3)2NH2. It is one of several isomeric xylidines. It is a colorless viscous liquid. Commercially significant derivatives include Solvent Yellow 30, Solvent Red 22, Acid Red 65, and Solvent Red 26.


2,5-Xylidine, Production
Like many xylidines, it is prepared by nitration of the corresponding xylene followed by reduction of the nitroxylene. Reduction can be effected with HCl/Fe, but usually is achieved by catalytic hydrogenation:


2,5-Xylidine, Safety
It is mutagenic and tumor-inducing. Acute toxicity of xylidines is modest as indicated by LD50 (rats, oral) are in the range 0.1-1 g/kg.


2,5-diamino-6-(ribosylamino)-4(3H)-pyrimidinone 5'-phosphate reductase
2,5-diamino-6-(ribosylamino)-4(3H)-pyrimidinone 5'-phosphate reductase (EC , 2,5-diamino-6-ribosylamino-4(3H)-pyrimidinone 5'-phosphate reductase, MjaRED, MJ0671 (gene)) is an enzyme with systematic name 2,5-diamino-6-(5-phospho-D-ribosylamino)pyrimidin-4(3H)-one:NAD(P)+ oxidoreductase. This enzyme catalyses the following chemical reaction


2,5-diamino-6-(ribosylamino)-4(3H)-pyrimidinone 5'-phosphate reductase
The reaction proceeds in the opposite direction. A step in riboflavin biosynthesis, NADPH and NADH functions equally well as a reductant.


2,5-diaminovalerate transaminase
In enzymology, a 2,5-diaminovalerate transaminase (EC ) is an enzyme that catalyzes the chemical reaction


2,5-diaminovalerate transaminase
Thus, the two substrates of this enzyme are 2,5-diaminopentanoate and 2-oxoglutarate, whereas its two products are 5-amino-2-oxopentanoate and L-glutamate.


2,5-diaminovalerate transaminase, Nomenclature
This enzyme belongs to the family of transferases, specifically the transaminases, which transfer nitrogenous groups. The systematic name of this enzyme class is 2,5-diaminopentanoate:2-oxoglutarate aminotransferase. Other names in common use include diamino-acid transaminase, and diamino acid aminotransferase.


2,5-didehydrogluconate reductase
In enzymology, a 2,5-didehydrogluconate reductase (EC ) is an enzyme that catalyzes the chemical reaction


2,5-didehydrogluconate reductase
Thus, the two substrates of this enzyme are 2-dehydro-D-gluconate and NADP+, whereas its 3 products are 2,5-didehydro-D-gluconate, NADPH, and H+.


2,5-didehydrogluconate reductase
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 2-dehydro-D-gluconate:NADP+ 2-oxidoreductase. Other names in common use include 2,5-diketo-D-gluconate reductase, and YqhE reductase.


2,5-didehydrogluconate reductase, Structural studies
As of late 2007, only one structure has been solved for this class of enzymes, with the PDB accession code .


2,5-dihydroxypyridine 5,6-dioxygenase
In enzymology, a 2,5-dihydroxypyridine 5,6-dioxygenase (EC ) is an enzyme that catalyzes the chemical reaction


2,5-dihydroxypyridine 5,6-dioxygenase
The 2 substrates of this enzyme are 2,5-dihydroxypyridine and O2, whereas its product is N-formylmaleamic acid.


2,5-dihydroxypyridine 5,6-dioxygenase
This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O2 as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). The oxygen incorporated need not be derived from O2. It employs one cofactor, iron.


2,5-dihydroxypyridine 5,6-dioxygenase, Nomenclature
The systematic name of this enzyme class is 2,5-dihydroxypyridine:oxygen 5,6-oxidoreductase. Other names in common use include 2,5-dihydroxypyridine oxygenase, and pyridine-2,5-diol dioxygenase.


2,5-diketocamphane 1,2-monooxygenase
2,5-diketocamphane 1,2-monooxygenase (EC , 2,5-diketocamphane lactonizing enzyme, ketolactonase I, 2,5-diketocamphane 1,2-monooxygenase oxygenating component, 2,5-DKCMO, camphor 1,2-monooxygenase, camphor ketolactonase I) is an enzyme with systematic name (+)-bornane-2,5-dione,NADH:oxygen oxidoreductase (1,2-lactonizing). This enzyme catalyses the following chemical reaction


2,5-dioxopiperazine hydrolase
In enzymology, a 2,5-dioxopiperazine hydrolase (EC ) is an enzyme that catalyzes the chemical reaction


2,5-dioxopiperazine hydrolase
Thus, the two substrates of this enzyme are 2,5-dioxopiperazine and H2O, whereas its product is glycylglycine.


2,5-dioxopiperazine hydrolase
This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in cyclic amides. The systematic name of this enzyme class is 2,5-dioxopiperazine amidohydrolase. Other names in common use include cyclo(Gly-Gly) hydrolase, and cyclo(glycylglycine) hydrolase.


2,5-dioxovalerate dehydrogenase
In enzymology, a 2,5-dioxovalerate dehydrogenase (EC ) is an enzyme that catalyzes the chemical reaction


2,5-dioxovalerate dehydrogenase
The 3 substrates of this enzyme are 2,5-dioxopentanoate, NADP+, and H2O, whereas its 3 products are 2-oxoglutarate, NADPH, and H+.


2,5-dioxovalerate dehydrogenase
This enzyme belongs to the family of oxidoreductases, specifically those acting on the aldehyde or oxo group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 2,5-dioxopentanoate:NADP+ 5-oxidoreductase. Other names in common use include 2-oxoglutarate semialdehyde dehydrogenase, and alpha-ketoglutaric semialdehyde dehydrogenase. This enzyme participates in ascorbate and aldarate metabolism.


2,500-year celebration of the Persian Empire
The 2,500-year celebration of the Persian Empire, officially known as the 2,500th Year of the Foundation of the Imperial State of Iran, was a national event in Iran that consisted of an elaborate set of grand festivities and took place from 12–16 October 1971 to celebrate the founding of the ancient Achaemenid Persian Empire by Cyrus the Great. The intent of the celebration was to highlight Iran's ancient civilization and history as well as to showcase its contemporary advances under Mohammad Reza Pahlavi, the last Shah of Iran.


2,500-year celebration of the Persian Empire
Some later historians came to believe that this massive celebration contributed to events that ultimately culminated in the 1979 Iranian Revolution, which replaced the Persian monarchy with an Islamic republic. The revolution was led by Ruhollah Khomeini, an Ayatollah who garnered support from the Iranian people, various leftist and Islamist organizations, and student movements to overthrow the Shah and establish the present-day Islamic Republic of Iran, for which he served as Supreme Leader from 1979 to 1989. The event has been described as the most expensive party ever held in modern history.


2,500-year celebration of the Persian Empire, Planning
The planning for the party took a year, according to the 2016 BBC Storyville documentary, Decadence and Downfall: The Shah of Iran's Ultimate Party. The filmmakers interviewed people tasked by the Shah to organize the party. The Cyrus Cylinder served in the official logo as the symbol for the event. With the decision to hold the main event at the ancient city of Persepolis, near Shiraz, the local infrastructure had to be improved, including the Shiraz International Airport and a highway to Persepolis.


2,500-year celebration of the Persian Empire, Planning
While the press and supporting staff would be housed in Shiraz, the main festivities were planned for Persepolis. An elaborate tent city was planned to house attendees. The area around Persepolis was cleared of snakes and other vermin. Trees and flowers were planted, and 50,000 song birds were imported from Europe. Other events were scheduled for Pasargadae, the site of the Tomb of Cyrus, as well as Tehran.


2,500-year celebration of the Persian Empire, Tent City of Persepolis
The Tent City (also called Golden City) was planned by the Parisian interior-design firm of Maison Jansen on 160 acres (0.65 km2). They referred to the meeting between Francis I of France and Henry VIII of England at the Field of the Cloth of Gold in 1520. Fifty 'tents' (prefabricated luxury apartments with traditional Persian tent-cloth surrounds) were arranged in a star pattern around a central fountain. Numerous trees were planted around them in the desert, to recreate how ancient Persepolis would have looked. Each tent was provided with direct telephone and telex connections for attendees to their respective countries. The entire celebration was televised to the world by way of a satellite connection from the site.


2,500-year celebration of the Persian Empire, Tent City of Persepolis
The large 'Tent of Honor' was designed for the reception of the dignitaries. The 'Banqueting Hall' was the largest structure, and measured 68 by 24 metres (223 ft × 79 ft). The tent site was surrounded by gardens of trees and other plants flown in from France and adjacent to the ruins of Persepolis. Catering services were provided by Maxim's de Paris, which closed its restaurant in Paris for almost two weeks to provide for the glittering celebrations. Legendary hotelier Max Blouet came out of retirement to supervise the banquet. Lanvin designed the uniforms of the Imperial Household. 250 red Mercedes-Benz 600 limousines were used to chauffeur guests from the airport and back. The dinnerware was created using Limoges porcelain and linen by D. Porthault.


2,500-year celebration of the Persian Empire, Festivities
The festivities were opened on 12 October 1971, when the Shah and the Shahbanu paid homage to Cyrus the Great at his mausoleum at Pasargadae. For the next two days, the Shah and his wife greeted arriving guests, often directly at Shiraz's airport. On 14 October, a grand gala dinner took place in the Banqueting Hall in celebration of the birthday of the Shahbanu. Sixty members of royal families and heads of state were assembled at the single large serpentine table in the Banqueting Hall. The official toast was raised with a Dom Perignon Rosé 1959.


2,500-year celebration of the Persian Empire, Festivities
The food and the wine for the celebration were provided by the Parisian restaurant Maxim's. 600 guests dined over five and a half hours, thus making for the longest and most lavish official banquet in modern history as recorded in successive editions of the Guinness Book of World Records. A son et lumière show, the Polytope of Persepolis designed by Iannis Xenakis and accompanied by the specially-commissioned electronic music piece Persepolis, concluded the evening.


2,500-year celebration of the Persian Empire, Festivities
The next day saw a huge military parade of armies of different Iranian empires covering two and half millennia by 1,724 men of the Iranian armed forces, all in period costume, followed by representatives of the Imperial Armed Forces, with a large military band, manned by military musicians and providing the music for the parade, split into two - the modern band playing in Western instruments and a traditional band wearing uniforms of the bandsmen from different eras of Iranian history. In the evening, a less formal "traditional Persian party" was held in the Banqueting Hall as the concluding event at Persepolis.


2,500-year celebration of the Persian Empire, Festivities
On the final day, the Shah inaugurated the Shahyad Tower (later renamed the Azadi Tower after the Iranian Revolution) in Tehran to commemorate the event. The tower was also home to the Museum of Persian History. In it was displayed the Cyrus Cylinder, which the Shah promoted as "the first human rights charter in history". The cylinder was also the official symbol of the celebrations, and the Shah's first speech at Cyrus' tomb praised the freedom that it had proclaimed, two and a half millennia previously. The festivities were concluded with the Shah paying homage to his father, Reza Shah Pahlavi, at his mausoleum.


2,500-year celebration of the Persian Empire, Festivities
The event brought together the rulers of two of the three oldest extant monarchies, the Shah and Emperor Haile Selassie I of Ethiopia. Emperor Hirohito of Japan was represented by his youngest brother, Prince Mikasa. By the end of the decade, both the Ethiopian and Iranian monarchies had ceased to exist.


2,500-year celebration of the Persian Empire, Security
Security was a major concern. Persepolis was a favoured site for the festivities as it was isolated and thus could be tightly guarded, a very important consideration when many of the world's leaders were gathered there. Iran's security services, SAVAK, captured and took into "preventive custody" anyone that it suspected of being a potential threat.


2,500-year celebration of the Persian Empire, Criticism
The Ministry of the Court placed the cost at $17 million (at that time); Ansari, one of the organizers, puts it at $22 million (at that time). The actual figure is difficult to calculate exactly and is a partisan issue.


2,500-year celebration of the Persian Empire, List of guests
Queen Elizabeth II had been advised not to attend, with security being an issue. The Duke of Edinburgh and Princess Anne represented her instead. Other major leaders who did not attend were Richard Nixon and Georges Pompidou. Nixon had initially planned to attend but later changed his mind and sent Spiro Agnew instead.


2,500-year celebration of the Persian Empire, List of guests
Some materials say that the attendee of China was Guo Moruo. According to his daughter, Guo was originally planned to attend, but he fell ill on the way arriving and then-Chinese Ambassador to Pakistan Zhang Tong attended instead.


2,500-year celebration of the Persian Empire, Film
Iran's National Film Board produced a documentary of the celebrations, titled Forugh-e Javidan (فروغ جاویدان) in Persian and Flames of Persia in English. Farrokh Golestan directed, and Orson Welles who had said of the event "This was no party of the year, it was the celebration of 25 centuries!" agreed to narrate the English text, written by Macdonald Hastings, in return for the Shah's brother-in-law funding Welles' own film, The Other Side of the Wind. The film was aimed at a Western audience. Despite a requirement to show the film in 60 cinemas in Tehran, its "overheated rhetoric" and popular resentment at the extravagance of the event meant it did poorly at the domestic box office.


2,500-year celebration of the Persian Empire, Today
Persepolis remains a major tourist attraction in Iran and apparently there are suggestions to rehabilitate the archeological site as it is a proclamation of Iranian history. In 2005, it was visited by nearly 35,000 people during the Iranian new year holiday.


2,500-year celebration of the Persian Empire, Today
The tent city remained operating until 1979 for private and government rent, when it was looted after the Iranian Revolution and the departure of the Shah. The iron rods for the tents and roads built for the festival area still remain and are open to the public, but there are no markers making any reference to what they were originally for. The dedicated Shahyad Tower remains as a major landmark in Tehran, although it was renamed Azadi Tower in 1979.


2,6-Di-tert-butylphenol
2,6-Di-tert-butylphenol is an organic compound with the structural formula 2,6-((CH3)3C)2C6H3OH. This colorless solid alkylated phenol and its derivatives are used industrially as UV stabilizers and antioxidants for hydrocarbon-based products ranging from petrochemicals to plastics. Illustrative of its usefulness, it prevents gumming in aviation fuels.


2,6-Di-tert-butylphenol, Production
2,6-Di-tert-butylphenol is prepared industrially via the Friedel–Crafts alkylation of phenol with isobutene catalyzed by aluminium phenoxide:


2,6-Di-tert-butylphenol, Applications
2,6-di-tert-butylphenol is a precursor to more complex compounds used as antioxidants and light-protection agents for the stabilization for polymers. Of particular note is methyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate (CAS# 6386-38-5), which is formed by the Michael addition of methyl methacrylate. This compound is used as a feedstock in the synthesis of more complex antioxidants such as Irganox 1098. 2,6-Di-tert-butylphenol is also used in the synthesis of CGP-7930, probucol, and nicanartine.


2,6-Di-tert-butylphenol, Safety and regulation
2,6-Di-tert-butylphenol is covered by the U.S. Department of Transportation Code of Federal Regulations 49 CFR 172.101, Appendix B (20 Dec 2004). This substance is designated by the U.S. Department of Transportation (DOT) as a marine pollutant.


2,6-Di-tert-butylpyridine
This is the current revision of this page, as edited by Fswitzer4 (talk | contribs) at 14:26, 22 June 2020 (Added FDA UNII). The present address (URL) is a permanent link to this version.


2,6-Di-tert-butylpyridine
2,6-Di-tert-butylpyridine is an organic compound with the formula (Me3C)2C5H3N. This colourless, oily liquid is derived from pyridine by replacement of the two H atoms with tert-butyl groups. It is a hindered base. For example, it can be protonated, but it does not form an adduct with boron trifluoride.


2,6-Di-tert-butylpyridine, Preparation
2,6-Di-tert-butylpyridine is prepared by the reaction of tert-butyllithium with pyridine. The synthesis is reminiscent of the Chichibabin reaction.


2,6-Di-tert-butylpyridine, Preparation
Some related bulky pyridine compounds have been described, including 2,4,6-tri-t-butylpyridine. and 2,6-di-tert-butyl-4-methylpyridine.


2,6-Diacetylpyridine
2,6-Diacetylpyridine is an organic compound with the formula C5H3N(C(O)CH3)2. It is a white solid that is soluble in organic solvents. It is a disubstituted pyridine. It is a precursor to ligands in coordination chemistry.


2,6-Diacetylpyridine, Synthesis
The synthesis of 2,6-diacetylpyridine begins with oxidation of the methyl groups in 2,6-lutidine to form dipicolinic acid. This process has been well established with potassium permanganate and selenium dioxide. The diketone can be formed from the diester of picolinic acid groups through a Claisen condensation. The resulting adduct can be decarboxylated to give diacetylpyridine.


2,6-Diacetylpyridine, Synthesis
Treating 2,6-pyridinedicarbonitrile with methylmagnesium bromide provides an alternative synthesis for the diketone.


2,6-Diacetylpyridine, Precursor to Schiff base ligands
Diacetylpyridine is a popular starting material for ligands in coordination chemistry, often via template reactions. The diiminopyridine (DIP) class of ligands can be formed from diacetylpyridine through Schiff base condensation with substituted anilines. Diiminopyridine ligands have been the focus of much interest due to their ability to traverse a wide range of oxidation states.


2,6-Diacetylpyridine, Precursor to Schiff base ligands
In azamacrocycle chemistry, diacetylpyridines can undergo the same Schiff base condensation with N1-(3-aminopropyl)propane-1,3-diamines. The product of the condensation can be hydrogenated to yield macrocyclic tetradentate ligands. Similar penta- and hexadentate ligands have been synthesized by varying the polyamine chain.


2,6-Diaminopurine
2,6-diaminopurine (2,6-DAP, also known as 2-aminoadenine) is a compound once used in the treatment of leukemia. As the Z base, it is found instead of adenine (A) in the genetic material of some bacteriophage viruses.


2,6-Diaminopurine
In August 2011, a report, based on NASA studies with meteorites found on Earth, was published suggesting 2,6-diaminopurine and related organic molecules, including the DNA and RNA components adenine and guanine, may have been formed extraterrestrially in outer space.


2,6-Diaminopurine, In viruses
In cyanophage S-2L (Siphoviridae), diaminopurine is used instead of adenine (host evasion). Diaminopurine base (Z) pairs perfectly with thymine (T) as it is identical to adenine (A) but has an amine group at position 2 forming 3 intermolecular hydrogen bonds, eliminating the major difference between the two types of basepairs (weak:A-T and strong:C-G). This improved stability affects protein-binding interactions that rely on those differences.


2,6-Diaminopurine, In viruses
Four papers published April 2021 further describes the use and production of the Z-base. It is now known that:


2,6-Diaminopurine, In viruses
In August 2021, it was shown that DatZ, MazZ and PurZ are sufficient to replace some occurrence of A by Z in the bacterial genome of E. coli; expression of this system is toxic to the cell. The structures of MazZ (subtype 2) and PurZ are also determined, showing a possible link between PurZ and archaeal verions of PurA.


2,6-Diaminopurine, Biosynthesis
2-aminoadenine is produced in two steps. The enzyme MazZ (homolgous to MazG, EC 3.6.1.8) first performs:


2,6-Diaminopurine, Biosynthesis
The enzyme PurZ (homolgous to PurA, EC 6.3.4.4) then performs:


2,6-Diaminopurine, Biosynthesis
The resulting dSMP is processed by host enzymes analogously to adenylosuccinate to produce dZTP.


2,6-Diaminopurine, In cellular life
2,6-DAP was used to treat leukemia since as early as 1951. It is known to arrest progression of cell cycle in mouse leukemia cells by 1989. Cancer cells are known to become resistant to DAP by losing their adenine phosphoribosyltransferase (APRT) function, a process shared with E. coli.


2,6-Diaminopurine, In cellular life
DAP derivatives are in vitro antivirals useful against pseudorabies virus, a economically important livestock disease. This base, in its free form, is able to correct UGA nonsense mutations by encouraging translational readthrough, through the inhibition of FTSJ1.


2,6-Diaminopurine, Bioengineering
In bioengineering, anti-miRNA oligonucleotides (specifically, the serinol nucleic acid [SNA] type) incorporating base Z instead of A show enhanced binding to RNA.


2,6-Diaminopurine, Bioengineering
DAP is used similar to other nuclear acid analogues in the investigation of enzyme structures and mechanisms.


2,6-Dibromoquinonechlorimide
2,6-Dibromoquinonechlorimide is a chemical used in chemical analysis and chromatography to detect phenolic chemicals. In the presence of phenolic substances it turns indigo in colour. In the presence of aflatoxin it turns green. 2,6-Dibromoquinonechlorimide explodes if heated above 120 °C and decomposes slowly over 60 °C.


2,6-Dibromoquinonechlorimide
2,6-Dibromoquinonechlorimide is used in a buffer solution around pH 9.4. It is very sensitive and can detect down to 0.05 parts per million of phenols. The mechanism is a reaction of the chlorimide group (=NCl) with the phenol to produce an indophenol, with two rings joined via an =N- link.


2,6-Dichloroaniline
2,6-Dichloroaniline is an organic compound with the formula C6H3Cl2(NH2). It is one of several isomers of dichloroaniline. It is a colorless or white solid. Derivatives include the drugs clonidine and diclofenac.


2,6-Dichloroaniline, Preparation
In the laboratory, it can be prepared by halogenation of sulfanilamide followed by desulfonation.


2,6-Dichlorobenzonitrile
2,6-Dichlorobenzonitrile (DCBN or dichlobenil) is an organic compound with the chemical formula C6H3Cl2CN. It is a white solid that is soluble in organic solvents. It is widely used as an herbicide.


2,6-Dichlorobenzonitrile, Mechanism of action
It has herbicidal properties killing young seedlings of both monocot and dicot species. DCBN interferes with cellulose synthesis. DCBN adapted cell walls use minimal amounts of cellulose, instead relying on Ca2+-bridge pectates.


2,6-Dichlorobenzonitrile, Safety
In 1971 in the U.S. State of California, their department of agriculture reported, "Dichlobenil kills the roots of many species, but not all; further, the killing does not extend much beyond the portion actually soaked."


2,6-Dichlorobenzonitrile, Safety
In 1996, the University of California's Statewide Integrated Pest Management Project reported:


2,6-Dichlorobenzonitrile, Safety
Dosages were difficult to control... and as a result soaking or spraying methods are no longer used. The current application method involves applying metam-sodium products in foam carriers (similar to shaving cream).


2,6-Dichlorobenzonitrile, Safety
The U.S. Food & Drug Administration (FDA, a major operational division of the U.S. Department of Health & Human Services) mentions "dichlobenil" in a report entitled "Herbicidal suppression of bracken and effects on forage production."


2,6-Dichlorobenzonitrile, Safety
The U.S. Department of Energy - Bonneville Power Administration has reported "high potential" for dichlobenil to enter groundwater.


2,6-Dichlorobenzonitrile, Safety, Residue
Inland Fisheries Ireland has reported, "The dichlobenil residue in water almost completely dissipates in 5 to 6 months."


2,6-Dichlorobenzonitrile, Safety, Toxicity and environment
Since 1995, the U.S. National Institutes of Health has warned about potential damage to humans during indoor usage (see products listed, below):


2,6-Dichlorobenzonitrile, Safety, Toxicity and environment
Leave all windows open and fans operating... Put all pets outdoors, and take yourself any your family away from treated areas for at least the length of time prescribed on the label.


2,6-Dichlorobenzonitrile, Safety, Toxicity and environment
It is no longer approved for use within the EU. It has low solubility, is not highly volatile and has potential to leach into groundwater. It is moderately persistent in soils and very persistent in water. It is moderately toxic to mammals, aquatic organisms, honeybees and earthworms.


2,6-Dichlorobenzonitrile, Safety, Toxicity and environment
The report quotes a European Union regulatory effective date of 2009. The Inland Fisheries Ireland has reported:


2,6-Dichlorobenzonitrile, Safety, Toxicity and environment
The registration of all dichlobenil products (including Casoron G) was revoked in Ireland from 18th March 2009, under Commission Decision 2008/754/EC of 18th September 2008. A period of grace for the disposal, storage, placing on the market and use of existing stocks expired on 18th March 2010.


2,6-Dichlorobenzonitrile, Safety, Toxicity and environment
The London underground found itself in violation by using dichlobenil in September 2011. As of 2012, the United Nations' International Programme on Chemical Safety (IPCS) has advised that "the substance can be absorbed into the body by inhalation, through the skin and by ingestion...  A harmful concentration of airborne particles can be reached quickly when dispersed... The substance may have effects on the skin. This may result in chloracne." Further, it has advised


2,6-Dichlorobenzonitrile, Safety, Toxicity and environment
The substance is toxic to aquatic organisms. This substance does enter the environment under normal use. Great care, however, should be taken to avoid any additional release, for example through inappropriate disposal.


2,6-Dichlorobenzonitrile, Safety, Toxicity and environment
Particulate filter respirator adapted to the airborne concentration of the substance... Sweep spilled substance into covered sealable containers. If appropriate, moisten first to prevent dusting. Carefully collect remainder. Then store and dispose of according to local regulations.


2,6-Dichlorobenzonitrile, Safety, Toxicity and environment
While the ICPS warns strongly, "Do NOT let this chemical enter the environment," it does not note the contradiction that dichlobenil's usage is on the environment.


2,6-Dichlorobenzonitrile, Safety, Toxicity and environment
The U.S. Centers for Disease Control and Prevention (CDC) follows and cites the ICPS.


2,6-Dichlorobenzonitrile, Consumer products, United States
This partial list of consumer products with "dichlobenil" as an active ingredient:


2,6-Dichlorophenol
2,6-Dichlorophenol is a compound with formula C6H3Cl2OH. It is one of the six isomers of dichlorophenol. It is a colorless solid. Its pKa is 6.78, which is about 100x more acidic than 2-chlorophenol (8.52) and 1000x more acidic than phenol itself (9.95).


2,6-Dichlorophenol, Preparation
It can be produced in a multistep process from phenol, which is converted to its 4-sulfonic acid derivative. The resulting phenol sulfonic acid  chlorinates at the positions flanking the phenol. Hydrolysis releases the sulfonic acid group.


2,6-Dichlorophenol, Preparation
An alternative synthesis starts with the ethyl ester of 4-hydroxybenzoic acid, which chlorinates at the positions flanking the phenolic center. Ester hydrolysis followed by decarboxylation affords 2,6-dichlorophenol.


2,6-Dichloropyridine
2,6-Dichloropyridine is an organohalide with the formula C5H3Cl2N. A white solid, it is one of several isomers of dichlorpyridine. It serves as a precursor to the antibiotic enoxacin. 2,6-Dichoropyridine is produced by direct reaction of pyridine with chlorine. 2-Chloropyridine is an intermediate.


2,6-Dichloroquinone-4-chloroimide
2,6-Dichloroquinone-4-chloroimide (Gibbs reagent) is an organic compound used as an colorimetric indicator to detect phenolic compounds. Upon reaction with phenol itself, 2,6-dichlorophenolindophenol is formed, a chemical that is used as a redox indicator.


2,6-Diformylpyridine
2,6-Diformylpyridine is an organic compound with the formula C5H3N(CHO)2. The molecule features formyl groups adjacent to the nitrogen of pyridine. The compound is prepared by oxidation of 2,6-dimethylpyridine.


2,6-Dihydroxybenzoic acid
2,6-Dihydroxybenzoic acid (γ-resorcylic acid) is a dihydroxybenzoic acid. It is a very strong acid due to its intramolecular hydrogen bonding.


2,6-Dihydroxybenzoic acid
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2,6-Dihydroxypyridine
2,6-Dihydroxypyridine is an alkaloid with the molecular formula C5H3N(OH)2. It is a colorless solid. 2,6-Dihyroxypyridine is an intermediate in the degradation of nicotine.


2,6-Dihydroxypyridine, Preparation
2,6-Dihydroxypyridine is an intermediate in the degradation of nicotine by the aerobic bacterium Arthrobacter nicotinovorans. The following reaction shows the formation of the intermediate from L-nicotine of tobacco.


2,6-Dihydroxypyridine, Preparation
The figure represents the pathway for the degradation of L-nicotine by A. nicotinovorans to 2,6-dihydroxypyridine


2,6-Dihydroxypyridine, Preparation
Another reaction of 2,6-dihydroxypyridine highlights its function as a substrate for oxygenase. One example is the enzyme monooxygenase, which oxidizes the substrate by transferring one oxygen atom of O2 to the substrate. The other oxygen atom is reduced to water. The product of the oxidase reaction was determined to be 2,3,6-tri-hydroxypyridine because of the results of the stoichiometry as well as the results of the ultraviolet spectrum. This reaction can be shown by the following equation:


2,6-Dihydroxypyridine, Preparation
Arthrobacter oxydans, when grown on agar plates, were most active in the oxidation of 2,6-dihydroxypyridine.


2,6-Dihydroxypyridine, Structure and properties
The distribution of these tautomers is solvent-dependent. Studies show that tautomer II is most common in ethanol, water, and DMSO.


2,6-Dihydroxypyridine, Other Applications
2,6-Dihydroxypyridine has been investigated  in an oxidation method of dyeing hair. The process utilizes 2,6-dihydroxypyridine as a coupling agent, and 2,4,5,6-tetraaminopyrimidine as a primary intermediate. This oxidation method intensifies the color of the dyed hair for several days.


2,6-Dihydroxypyridine, Main Reactions
2,6-dihydroxypyridine is a key intermediate in the degradation of nicotine by certain bacteria. The enzyme 2,6-dihydroxypyridine-3-hydroxylase, which is produced in Escherichia coli, is responsible for catalyzing the sixth step of nicotine degradation in the bacterium Arthrobacter nicotinovoran. 2,6-dihydroxypyridine is hydroxylated by hydroperoxy-FAD. This reaction yields 2,3,6-tri-hydroxypyridine. This is shown in the following reaction::


2,6-Dihydroxypyridine, Main Reactions
2,6-dihydroxypyridine hydroxylase is a dimeric flavoprotein, with one bound FAD molecule attached. The reaction is NADH-dependent and the enzyme only accepts 2,6-dihydroxypyridine as a substrate. Furthermore, the enzyme is inhibited by 2,6-dimethoxypyridine and 2,3-dihydroxypyridine.


2,6-Diisopropylaniline
2,6-Diisopropylaniline is an organic compound with the formula H2NC6H3(CHMe2)2 (Me = CH3). It is a colorless liquid although, like many anilines, samples can appear yellow or brown. 2,6-Diisopropylaniline is a bulky aromatic amine that is often used to make ligands in coordination chemistry. The Schrock carbenes often are transition metal imido complexes derived from this aniline. Condensation with diacetylpyridine and acetylacetone gives, respectively, diiminopyridine and NacNac ligands.


2,6-Diisopropylnaphthalene
2,6-Diisopropylnaphthalene (2,6-DIPN) is an organic compound with the formula C10H6(i-Pr)2 (where i-Pr = isopropyl). 2,6-DIPN is one of several isomers of diisopropylnaphthalene. It is a white or colorless solid.


2,6-Diisopropylnaphthalene
2,6-DIPN is plant growth regulator. It helps inhibit the sprouting of potatoes during storage, especially in combination with chlorpropham. 2,6-DIPN is intended for use in the manufacturing of products intended to prevent sprouting of stored potatoes.


2,6-Dimethoxybenzoquinone
2,6-Dimethoxybenzoquinone (2,6-DMBQ) is a chemical compound, classified as a benzoquinone, that has been found in Rauvolfia vomitoria and in Tibouchina pulchra.


2,6-Dimethoxybenzoquinone, Toxicity
At physiological concentrations 2,6-dimethoxybenzoquinone is an antibacterial substance. At higher concentrations there is evidence that it is mutagenic, cytotoxic, genotoxic, and hepatotoxic. Some reports have challenged its mutagenicity and others  exclude such a possibility.


2,6-Dimethylnaphthalene
2,6-Dimethylnaphthalene (2,6-DMN) is a polycyclic aromatic hydrocarbon. It is one of the ten dimethylnaphthalene isomers, which are derived from naphthalene by the addition of two methyl groups.


2,6-Dimethylnaphthalene, Synthesis
Alkylated naphthalenes (methyl-, dimethyl-, and poly-methyl naphthalenes, thus including 2,6-DMN) are found in low concentrations in crude oil and coal tar. Separation is difficult, expensive, and requires a number of operations such as selective crystallization and adsorption, in addition to any isomerization reactions. Alternative routes to 2,6-DMN remains of interest.


2,6-Dimethylnaphthalene, Synthesis
In the "alkenylation process" butadiene (1) , o-xylene (2), and Sodium-potassium alloy (3) are used, which react to form 5-(ortho-tolyl)pent-2-ene (OTP, 3). OTP is subsequently cyclized to 1,5-dimethyltetraline (4). Dehydrogenation then provides 1,5-dimethylnaphthalene (1,5-DMN, 5). Finally, 1,5-DMN is isomerized to 2,6-DMN (6). In the final step, other mono-, di-, and tri-methylnaphthalenes are formed. More work is therefore required in separation of the mixture, which is done by selective crystallization.


2,6-Dimethylnaphthalene, Applications
2,6-Dimethylnaphthalene is mainly used for the preparation of 2,6-naphthalenedicarboxylic acid by oxidation of 2,6-dimethylnaphthalene in the liquid phase. 2,6-Naphthalenedicarboxylic acid is a monomer for the production of high-performance polymers, in particular poly (ethylene-2,6-naphthalene dicarboxylate) or shorter polyethylene naphthalate (PEN). That polyester is stronger and has a higher thermal resistance than the more frequently used polyethylene terephthalate (PET).


2,6-Dimethylnaphthalene, Applications
2,6-Dimethylnaphthalene undergoes ammoxidation to give the 2,6-dicyanonaphthalene, which can be hydrogenated to bis(aminomethyl)naphthalene, a precursor to dyes.


2,6-Dimethylpiperidine
2,6-Dimethylpiperidines are chemical compounds with the formula C5H8(CH3)2NH. Three stereoisomers exist: the achiral (R,S)-isomer and the chiral (R,R)/(S,S) enantiomeric pair. Dimethylpiperidines are derivatives of the heterocycle piperidine, wherein two hydrogen atoms are replaced by methyl groups.


2,6-Dimethylpiperidine
The 2,6-dimethylpiperidines are prepared by reduction of 2,6-dimethylpyridine (2,6-lutidine). The achiral isomer is the predominant isomer produced in this reaction.


2,6-Dimethylpiperidine
The 2,6-dimethylpiperidines are of interest for their conformational properties. The (R,S)-isomer exists largely in the chair conformation with equatorial methyl groups. The (R,R)/(S,S)-isomers are attractive chiral secondary amine building blocks.


2,6-Lutidine
2,6-Lutidine is a natural heterocyclic aromatic organic compound with the formula (CH3)2C5H3N. It is one of several dimethyl-substituted derivative of pyridine, all of which are referred to as lutidines. It is a colorless liquid with mildly basic properties and a pungent, noxious odor.


2,6-Lutidine, Occurrence and production
It was first isolated from the basic fraction of coal tar and from bone oil.


2,6-Lutidine, Occurrence and production
A laboratory route involves condensation of ethyl acetoacetate, formaldehyde, and an ammonia source to give a bis(carboxy ester) of a 2,6-dimethyl-1,4-dihydropyridine, which, after hydrolysis, undergoes decarboxylation.


2,6-Lutidine, Occurrence and production
It is produced industrially by the reaction of formaldehyde, acetaldehyde, and ammonia.


2,6-Lutidine, Uses
2,6-Lutidine has been evaluated for use as a food additive owing to its nutty aroma when present in solution at very low concentrations.


2,6-Lutidine, Uses
Due to the steric effects of the two methyl groups, 2,6-lutidine is less nucleophilic than pyridine. Protonation of lutidine gives lutidinium, [(CH3)2C5H3NH]+, salts of which are sometimes used as a weak acid because the conjugate base (2,6-lutidine) is so weakly coordinating. In a similar implementation, 2,6-lutidine is thus sometimes used in organic synthesis as a sterically hindered mild base. One of the most common uses for 2,6-lutidine is as a non-nucleophilic base in organic synthesis. It takes part in the formation of silyl ethers as shown in multiple studies.


2,6-Lutidine, Biodegradation
The biodegradation of pyridines proceeds via multiple pathways. Although pyridine is an excellent source of carbon, nitrogen, and energy for certain microorganisms, methylation significantly retards degradation of the pyridine ring. In soil, 2,6-lutidine is significantly more resistant to microbiological degradation than any of the picoline isomers or 2,4-lutidine. Estimated time for complete degradation was >30 days.


2,6-Lutidine, Toxicity
Like most alkylpyridines, the LD50 of 2,6-dimethylpyridine is modest, being 400 mg/kg (oral, rat).


2,6-Naphthalenedicarboxylic acid
2,6-Naphthalenedicarboxylic acid is an organic compound with the formula C10H6(CO2H)2. This colorless solid is one of several isomers of naphthalenedicarboxylic acid. It is a precursor to the high performance polyester polyethylene naphthalate (PEN, poly(ethylene-2,6-naphthalene dicarboxylate)). It is also used in the synthesis of some metal-organic frameworks.


2,6-Naphthalenedicarboxylic acid, Preparation
The conjugate base of 2,6-naphthalenedicarboxylic acid, when heated, isomerizes to the 1,6-isomer, which is readily converted to 1,6-naphthalenedicarboxylic acid. It is also produced by oxidation of 2,6-diisopropylnaphthalene.


2,6-Pyridinedicarbothioic acid
2,6-Pyridinedicarbothioic acid (PDTC) is an organosulfur compound that is produced by some bacteria. It functions as a siderophore, a small chelating agent with a high affinity for iron. Siderophores are deployed as ion scavengers for microbes. Siderophores solubilize compounds by forming strong complexes. PDTC is secreted by the soil bacteria Pseudomonas stutzeri and Pseudomonas putida.


2,6-Pyridinedicarbothioic acid, Synthesis and biosynthesis
PDTC can be synthesized by treating the pyridine-2,6-dicarboxylic acid (or its diacid dichloride) with H2S in dry pyridine:


2,6-Pyridinedicarbothioic acid, Synthesis and biosynthesis
This produces an orange 1:1 pyridinium salt of 2,6-pyridinedicarbothioate. Treatment of this salt with acid give PDTC, which can then be extracted with dichloromethane.


2,6-Pyridinedicarbothioic acid, Synthesis and biosynthesis
The biosynthesis of PDTC remains unclear although some insights can be deduced from the genetics. It is suggested that Pseudomonas stutzeri may have acquired at least one of the genes by lateral transfer from mycobacteria. In a proposed biosynthetic sequence pyridine-2,6-dicarboxylic acid, a known bacterial metabolite, is activated as its bis-adenosine monophosphate (AMP) derivative. The sulfur donor and its activation remain uncertain.


2,6-Pyridinedicarbothioic acid, Coordination chemistry
PDTC binds to both Fe2+ and Fe3+. The ferric complex is brown, whereas the ferrous complex is blue. In the presence of air, the ferrous complex oxidizes to the ferric compound. It is iron selective as only the Fe complex is soluble in water. PDTC is produced mainly during the exponential phase of bacterial growth. The conditions at which Pseudomonas produces PDTC is 25 °C, pH=8 and sufficient aeration.


2,6-Xylenol
2,6-Xylenol is a chemical compound which is one of the six isomers of xylenol. It is also commonly known as 2,6-dimethylphenol (DMP).


2,6-Xylenol
A known application of DMP is in the synthesis of Mexiletine.


2,6-Xylenol, Production
2,6-DMP can be produced by the direct methylation of phenol. This is carried out with gaseous phenol and methanol at elevated temperatures in the presence of a catalyst


2,6-Xylenol, Related polymers
2,6-Xylenol is a monomer for poly(p-phenylene oxide) engineering resins through carbon - oxygen oxidative coupling. Carbon-to-carbon dimerization is also possible. In one study 2,6-xylenol is oxidized with iodosobenzene diacetate with a fivefold excess of the phenol.


2,6-Xylenol, Related polymers
In the first step of the proposed reaction mechanism the acetyl groups in the iodine compound are replaced with the phenol. This complex dissociates into an aryl radical anion and a phenoxy residue. The two aryl radicals recombine forming a new carbon-carbon covalent bond and subsequently lose two protons in a rearomatization step. The immediate reaction product is a diphenoquinone as result of a one-step 4-electron oxidation. It is nevertheless possible to synthesize the biphenol compound via a comproportionation of the quinone with xylenol already present. In this reaction sequence the hypervalent iodine reagent is eventually reduced to phenyliodine.


2,6-Xylidine
2,6-Xylidine is an organic compound with the formula C6H3(CH3)2NH2. It is one of several isomeric xylidines. It is a colorless viscous liquid. Commercially significant derivatives are the anesthetics lidocaine, bupivacaine, mepivacaine, and etidocaine.


2,6-Xylidine, Production and reactions
Many xylidines are prepared by nitration of a xylene followed by hydrogenation of the nitroaromatic, but this approach is not efficient for this isomer. Instead, it is prepared from by treatment of the related xylenol with ammonia in the presence of oxide catalysts.


2,6-beta-fructan 6-levanbiohydrolase
2,6-beta-fructan 6-levanbiohydrolase (EC , beta-2,6-fructan-6-levanbiohydrolase, 2,6-beta-D-fructan 6-levanbiohydrolase, levanbiose-producing levanase, 2,6-beta-D-fructan 6-beta-D-fructofuranosylfructohydrolase) is an enzyme with systematic name (2->6)-beta-D-fructofuranan 6-(beta-D-fructosyl)-D-fructose-hydrolase. This enzyme catalyses the following chemical reaction


2,6-dihydroxypseudooxynicotine hydrolase
2,6-dihydroxypseudooxynicotine hydrolase (EC ) is an enzyme with systematic name 1-(2,6-dihydroxypyridin-3-yl)-4-(methylamino)butan-1-one hydrolase. This enzyme catalyses the following chemical reaction


2,6-dihydroxypseudooxynicotine hydrolase
The enzyme is present in the soil bacterium Arthrobacter nicotinovorans.


2,6-dihydroxypyridine 3-monooxygenase
In enzymology, a 2,6-dihydroxypyridine 3-monooxygenase (EC ) is an enzyme that catalyzes the chemical reaction


2,6-dihydroxypyridine 3-monooxygenase
The 4 substrates of this enzyme are 2,6-dihydroxypyridine, NADH, H+, and O2, whereas its 3 products are 2,3,6-trihydroxypyridine, NAD+, and H2O.


2,6-dihydroxypyridine 3-monooxygenase
This enzyme belongs to the family of oxidoreductases, specifically those acting on paired donors, with O2 as oxidant and incorporation or reduction of oxygen. The oxygen incorporated need not be derived from O2 with NADH or NADPH as one donor, and incorporation of one atom o oxygen into the other donor. The systematic name of this enzyme class is 2,6-dihydroxypyridine,NADH:oxygen oxidoreductase (3-hydroxylating). This enzyme is also called 2,6-dihydroxypyridine oxidase. It has 2 cofactors: FAD,  and Flavoprotein.


2,6-dioxo-6-phenylhexa-3-enoate hydrolase
In enzymology, a 2,6-dioxo-6-phenylhexa-3-enoate hydrolase (EC ) is an enzyme that catalyzes the chemical reaction


2,6-dioxo-6-phenylhexa-3-enoate hydrolase
Thus, the two substrates of this enzyme are 2,6-dioxo-6-phenylhexa-3-enoate and H2O, whereas its two products are benzoate and 2-oxopent-4-enoate.


2,6-dioxo-6-phenylhexa-3-enoate hydrolase
This enzyme belongs to the family of hydrolases, specifically those acting on carbon-carbon bonds in ketonic substances. The systematic name of this enzyme class is 2,6-dioxo-6-phenylhexa-3-enoate benzoylhydrolase. This enzyme is also called HOHPDA hydrolase. This enzyme participates in biphenyl degradation and fluorene degradation.


2,6-dioxo-6-phenylhexa-3-enoate hydrolase, Structural studies
As of late 2007, 3 structures have been solved for this class of enzymes, with PDB accession codes , , and .


2,7,4'-Trihydroxyisoflavanone 4'-O-methyltransferase
2,7,4'-Trihydroxyisoflavanone 4'-O-methyltransferase (EC , SAM:2,7,4'-trihydroxyisoflavanone 4'-O-methyltransferase, HI4'OMT, HMM1, MtIOMT5) is an enzyme with systematic name S-adenosyl-L-methionine:2,7,4'-trihydroxyisoflavanone 4'-O-methyltransferase . This enzyme catalyses the following chemical reaction


2,7-Dihydrothiepine
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2,8-Dihydroxyadenine
2,8-Dihydroxyadenine is a derivative of adenine which accumulates in 2,8 dihydroxy-adenine urolithiasis. The poorly soluble purine 2,8-dihydroxyadenine is excreted in the urine because of a deficiency in the adenine salvage enzyme adenine phosphoribosyltransferase. The defect is inherited as an autosomal recessive trait; the homozygous state is associated with high urinary levels of 2,8-dihydroxyadenine and with crystalluria, calculus formation, and potential nephrotoxicity. The condition primarily presents as renal obstructive disease, but some patients have presented with advanced kidney failure. Allopurinol therapy appears to be effective. 2, 8-dihydroxyadenine formation can be easily controlled with allopurinol, which is administered in a dose of 300 mg/day in adults (10 mg/kg/day in children) in the absence of kidney failure.


2,8-Dihydroxyhexahydrochrysene
2,8-Dihydroxyhexahydrochrysene (2,8-DHHHC) is a synthetic, nonsteroidal weak estrogen with approximately 1/2,000th the estrogenic potency of the structurally-related estrogen diethylstilbestrol. It is said to be intermediate in structure between estradiol and hexestrol, but conversely to both of them, is drastically less potent in comparison.


2,N,N-TMT
2,N,N-Trimethyltryptamine, 2,N,N-TMT, or 2-Me-DMT is a tryptamine derivative that is a psychedelic drug. It was invented by Alexander Shulgin and reported in his book TiHKAL (#34). It is claimed to show psychoactive effects at a dosage of 50–100 mg orally, but these are relatively mild compared to other similar drugs, suggesting that while the 2-methyl group has blocked the binding of metabolic enzymes, it is also interfering with binding to the 5HT2A receptor target that mediates the hallucinogenic effects of these drugs.


2,N,N-TMT, Legal status
Sweden's public health agency suggested classifying 2-Me-DMT as a hazardous substance, on May 15, 2019.


2,alpha-DMT
2,alpha-DMT, or 2,α-dimethyltryptamine, is a tryptamine and a lesser-known psychedelic drug. It is the 2,a-dimethyl analog of DMT. 2,α-DMT was first synthesized by Alexander Shulgin. In his book TiHKAL (Tryptamines I Have Known and Loved), Shulgin lists the dosage as 300-500 mg, and the duration as 7–10 hours. 2,α-DMT causes mydriasis and paresthesia. It also produces a calm, drunk-like feeling. Very little data exists about the pharmacological properties, metabolism, and toxicity of 2,α-DMT.


2-(1,2-epoxy-1,2-dihydrophenyl)acetyl-CoA isomerase
2-(1,2-epoxy-1,2-dihydrophenyl)acetyl-CoA isomerase (EC , paaG (gene), 1,2-epoxyphenylacetyl-CoA isomerase) is an enzyme with systematic name 2-(1,2-epoxy-1,2-dihydrophenyl)acetyl-CoA isomerase. This enzyme catalyses the following chemical reaction


2-(1-Hexyloxyethyl)-2-devinyl pyropheophorbide-a
2-(1-Hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH) is a photosensitiser chemical that is used in photodynamic therapy.


2-(1-Hexyloxyethyl)-2-devinyl pyropheophorbide-a, Clinical trials
A phase I/II clinical trial started in 1997 for esophageal cancer.


2-(1-Hexyloxyethyl)-2-devinyl pyropheophorbide-a, Clinical trials
A phase II trial for non-small cell lung cancer is due to run from 2007 to 2011.


2-(2-(4-Methyl-3-cyclohexen-1-yl)propyl)cyclopentanone
2-[2-(4-Methyl-3-cyclohexen-1-yl)propyl]cyclopentanone (trade name by Givaudan: Nectaryl) is an organic compound belonging to the group of ketones and cycloalkanes. The compound is used as a fragrance.


2-(2-(4-Methyl-3-cyclohexen-1-yl)propyl)cyclopentanone, Synthesis
The synthesis of the compound is carried out by a radical addition of cyclopentanone to (+)-limonene under oxygen in acetic acid. As a catalyst, manganese(II) acetate and cobalt(II) acetate are used.


2-(2-(4-Methyl-3-cyclohexen-1-yl)propyl)cyclopentanone, Properties
The flash point of the compound is 162.5 °C, and the autoignition temperature is 294 °C. The specific rotation is reported to be [α]D20=+228–235° (1 M; chloroform)


2-(2-(4-Methyl-3-cyclohexen-1-yl)propyl)cyclopentanone, Properties
In general, the compound features a fruity apricot-like odor. Of the four stereo isomers, (2R,2′S,1′′R)-Nectaryl and (2R,2′R,1′′R)-Nectaryl contribute especially to the compound's odor, the odor detection threshold lies at 0.094 ng·l−1 and 0.112 ng·l−1, respectively. In contrast to that, the other stereo isomers show an unspecific fruity odor, the odor detection threshold are 11.2 ng·l−1 and 14.9 ng·l−1 which is much higher.


2-(2-(4-Methyl-3-cyclohexen-1-yl)propyl)cyclopentanone, Properties
The tenacity on blotter (the time during which the compound is smellable with unchanged characteristics) is reported to be three weeks.


2-(2-(4-Methyl-3-cyclohexen-1-yl)propyl)cyclopentanone, Uses
The substance is used as a fragrance in exemplary air conditioning products, perfumes and polishes.


2-(2-Ethoxyethoxy)ethanol
2-(2-Ethoxyethoxy)ethanol, also known under many trade names,  is the organic compound with the formula CH3CH2OCH2CH2OCH2CH2OH. It is a colorless liquid. It is a popular solvent for commercial applications. It is produced by the ethoxylation of ethanol.


2-(2-Ethoxyethoxy)ethanol, Applications
It is a solvent for dyes, nitrocellulose, paints, inks, and resins. It is a component of wood stains for wood, for setting the twist and conditioning yarns and cloth, in textile printing, textile soaps, lacquers, penetration enhancer in cosmetics, drying varnishes and enamels, and brake fluids. It used to determine the saponification values of oils and as a neutral solvent for mineral oil-soap and mineral oil-sulfated oil mixtures (giving fine dispersions in water)


2-(2-Hydroxyphenyl)-2H-benzotriazoles
2-(2-Hydroxyphenyl)-2H-benzotriazoles, also referred to as phenolic benzotriazoles, are an important class of UV absorbers comprising the benzotriazole building block.


2-(2-Hydroxyphenyl)-2H-benzotriazoles, Structure
The molecules are composed of substituted benzotriazoles with a phenyl group in the 2-position, which carries a hydroxy group in the ortho-position.


2-(2-Hydroxyphenyl)-2H-benzotriazoles, Use
2-(2-hydroxyphenyl)-2H-benzotriazoles are used as UV stabilizers in lacquers and plastics.


2-(2-Methoxyethoxy)ethanol
2-(2-Methoxyethoxy)ethanol, also known under trade names Methyl Carbitol, is an industrial solvent and is also commonly used as a Fuel System Icing Inhibitor (FSII) in jet fuels. It is a clear, colorless, hygroscopic liquid. Structurally it is an alcohol and an ether, with a formula  CH3OCH2CH2OCH2CH2OH. At direct contact it causes drying of skin by leaching fats, and is mildly irritating to the eyes. It is flammable.


2-(Dicyanomethylene)croconate
2-(Dicyanomethylene)croconate is a divalent anion with chemical formula C8N2O2−4 or ((N≡C−)2C=)(C5O4)2−. It is one of the pseudo-oxocarbon anions, as it can be described as a derivative of the croconate oxocarbon anion C5O2−5 through the replacement of one oxygen atom by a dicyanomethylene group =C(−C≡N)2.


2-(Dicyanomethylene)croconate
The anion was synthesized and characterized by A. Fatiadi in 1980, by hydrolysis of croconate violet treated with potassium hydroxide. It gives an orange solution in water.


2-(Diphenylphosphino)anisole
2-(Diphenylphosphino)anisole is the organophosphorus compound  with the formula (C6H5)2PC6H4-2-OCH3. It is a white solid that is soluble in organic solvents. The compound is used as a ligand in organometallic chemistry and homogeneous catalysis. It is the prototypical hemilabile ligand. This compound is prepared from 2-bromoanisole.


2-(Ethylamino)-1,2-diphenylethanone
2-(Ethylamino)-1,2-diphenylethanone (also known as α-ethylamino-deoxybenzoin, [α-(Ethylamino)benzyl]-(phenyl)-ketone and βk-Ephenidine) is a chemical compound which was first invented in 1955, researched by ICI in 1969 as an antidepressant, and subsequently claimed by AstraZeneca as an inhibitor of the enzyme 11β-Hydroxysteroid dehydrogenase type 1. No other pharmacological data has been disclosed, though its chemical structure closely resembles that of certain designer drug compounds such as ephenidine and N-ethylhexedrone.


2-(R)-hydroxypropyl-CoM dehydrogenase
In enzymology, a 2-(R)-hydroxypropyl-CoM dehydrogenase (EC ) is an enzyme that catalyzes the chemical reaction


2-(R)-hydroxypropyl-CoM dehydrogenase
Thus, the two substrates of this enzyme are 2-(R)-hydroxypropyl-CoM and NAD+, whereas its 3 products are 2-oxopropyl-CoM, NADH, and H+.


2-(R)-hydroxypropyl-CoM dehydrogenase
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 2-[2-(R)-hydroxypropylthio]ethanesulfonate:NAD+ oxidoreductase. This enzyme is also called 2-(2-(R)-hydroxypropylthio)ethanesulfonate dehydrogenase.


2-(R)-hydroxypropyl-CoM dehydrogenase, Structural studies
As of late 2007, only one structure has been solved for this class of enzymes, with the PDB accession code .


2-(S)-hydroxypropyl-CoM dehydrogenase
In enzymology, a 2-(S)-hydroxypropyl-CoM dehydrogenase (EC ) is an enzyme that catalyzes the chemical reaction


2-(S)-hydroxypropyl-CoM dehydrogenase
Thus, the two substrates of this enzyme are 2-(S)-hydroxypropyl-CoM and NAD+, whereas its 3 products are 2-oxopropyl-CoM, NADH, and H+.


2-(S)-hydroxypropyl-CoM dehydrogenase
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-OH group of donor with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 2-[2-(S)-hydroxypropylthio]ethanesulfonate:NAD+ oxidoreductase. This enzyme is also called 2-(2-(S)-hydroxypropylthio)ethanesulfonate dehydrogenase.


2-(acetamidomethylene)succinate hydrolase
In enzymology, a 2-(acetamidomethylene)succinate hydrolase (EC ) is an enzyme that catalyzes the chemical reaction


2-(acetamidomethylene)succinate hydrolase
Thus, the two substrates of this enzyme are 2-(acetamidomethylene)succinate and H2O, whereas its 4 products are acetate, succinate semialdehyde, NH3, and CO2.


2-(acetamidomethylene)succinate hydrolase
This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in linear amides. The systematic name of this enzyme class is 2-(acetamidomethylene)succinate amidohydrolase (deaminating, decarboxylating). This enzyme is also called alpha-(N-acetylaminomethylene)succinic acid hydrolase. This enzyme participates in vitamin B6 metabolism.


2-(hydroxymethyl)-3-(acetamidomethylene)succinate hydrolase
In enzymology, a 2-(hydroxymethyl)-3-(acetamidomethylene)succinate hydrolase (EC ) is an enzyme that catalyzes the chemical reaction


2-(hydroxymethyl)-3-(acetamidomethylene)succinate hydrolase
Thus, the two substrates of this enzyme are 2-(hydroxymethyl)-3-(acetamidomethylene)succinate and H2O, whereas its 4 products are acetate, 2-(hydroxymethyl)-4-oxobutanoate, NH3, and CO2.


2-(hydroxymethyl)-3-(acetamidomethylene)succinate hydrolase
This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in linear amides. The systematic name of this enzyme class is 2-(hydroxymethyl)-3-(acetamidomethylene)succinate amidohydrolase (deaminating, decarboxylating). Other names in common use include compound B hydrolase, alpha-hydroxymethyl-alpha'-(N-acetylaminomethylene)succinic acid, and hydrolase. This enzyme participates in vitamin B6 metabolism.


2-1 road
A 2-1 road (2-minus-1 road) is a type of road with extra wide shoulders, and a smaller two-way lane in the middle for vehicles. The shoulders are to be used by pedestrians and cyclists, and if necessary by meeting vehicles. The purpose of the road is to give more space to pedestrians and cyclists and thereby avoid constructing new dedicated pedestrian and bicycle paths, especially in areas where new constructions are to be avoided or not possible.


2-1 road
The road-type is popular in Denmark where a third of all municipalities have at least one stretch of this type of road. Together with other traffic calming measures these roads have lowered traffic accidents with about 25%. Sweden started building this type of road in 2006 and is there called "bymiljöväg", or in English "village environment road", as it often goes through and between different dispersed settlements. There the roads have been met by critique from both residents and the police as they believe it will lead to more accidents. Drivers' behavior have also been criticized.


2-1-1
2-1-1 is a special abbreviated telephone number reserved in Canada and the United States as an easy-to-remember three-digit telephone number meant to provide information and referrals to health, human, and social service organizations.


2-1-1
Like the emergency telephone number 9-1-1, 2-1-1 is one of the eight N11 codes of the North American Numbering Plan (NANP).


2-1-1, History, United States
For many years, New York Telephone (now a unit of Verizon) used 2-1-1 as an automated credit request number for disconnected or misdialed calls. This service was in service from the 1970s through the early 2000s.


2-1-1, History, United States
Before the introduction of direct long-distance dialing, the long-distance operator was reached by dialing 2-1-1 in order to place a long-distance call. When the states in the US and  provinces in  Canada were assigned area codes in 1947 by The North American Numbering Plan, direct long distance dialing using the area code + local number was slowly introduced starting in 1951, eventually eliminating the use  of 211. After that, the local telephone providers designated "00" for long distance operator access.


2-1-1, History, United States
United Way of Metropolitan Atlanta was the first to introduce a 2-1-1 service in 1997. Many states began implementation plans soon after, aided by the United Way of America in partnership with the Alliance of Information and Referral Systems (AIRS). On July 20, 2000, the Federal Communications Commission (FCC) approved 2-1-1 for nationwide use as a short number in the United States along with 5-1-1 for transportation. In Texas, particularly in the Coastal Bend area, 2-1-1 is also the number to call for elderly and handicapped people needing evacuation assistance in the event of a pending disaster such as a hurricane.


2-1-1, History, United States
As of 2017, close to 95% of the population in the U.S. (including Puerto Rico and Washington, DC) has access to 2-1-1 services. More than 200 agencies, including United Ways, provide 2-1-1 services. The largest population without access to 2-1-1 is the metro-Chicago area. In 2017, the 2-1-1 network in the U.S. answered close to 15 million requests for assistance through phone, text, and web chat.


2-1-1, History, Canada
The Canadian Radio-television and Telecommunications Commission (CRTC) approved the use of 2-1-1 throughout Canada on August 9, 2001. The first Canadian 2-1-1 service opened in Toronto on June 13, 2002. 2-1-1 services are free of charge and multilingual in Canada.


2-1-1, History, Canada
As of October 2020, the whole of Canada, including the territories, has had access to 2–1-1 thanks to a nationwide expansion, following the COVID-19 pandemic.


2-1-1, History, Canada
In Canada, 2-1-1 offers free and confidential information and referral for all non emergency needs.


2-1-1, Operation
2-1-1 center hours vary. Many are open 24/7 to refer callers to organizations that provide services in such areas as:


2-1-1, Operation
Where available, 2-1-1 is operated by a private non-profit community-service organization, local government or local United Ways, which are part of the broader United Way Worldwide network. 2-1-1 provides information and referral to callers on where to obtain assistance from local and national social service programs, local and national governmental agencies and local and national non-profit organizations as well as where to volunteer or make a donation locally. Referrals are often given from databases accessed by call specialists. These databases are maintained by 2-1-1 staff following stringent data management guidelines. The databases are typically local but in some cases linked together to form statewide databases.


2-1-1, Operation
Many 2-1-1 centers are exploring Memorandums of Understanding with state and federal governments to facilitate the efficient handling of future disasters. Television or radio stations could easily tell citizens to call 2-1-1 in the event of an emergency. Call specialists at these centers would be informed of current disaster plans or places to receive help and could then inform the public of the correct course of action.


2-1-1, Operation
After Hurricanes Harvey, Irma, and Maria in Florida, Texas, Puerto Rico, and the Gulf Coast region, 2-1-1 centers were instrumental in coordinating with local government officials and providing information to communities before and after local disasters. Furthermore, 2-1-1 providers in Massachusetts, Connecticut, and Florida were called upon to provide assistance to individuals fleeing Puerto Rico's devastation.


2-1-1, Availability, United States
As of May 2017, the service is available in all 50 states and Washington, D.C. and 95% of the U.S. population has access to 2-1-1 services by dialing 2-1-1 on a landline or cell phone. In 2017, the 2-1-1 network answered close to 15 million requests for assistance by phone, text, and chat.


2-1-1, Availability, Canada
In Canada, 2-1-1 is available in the following places (starting dates in parentheses). Note that this list may be out-of-date; 2-1-1 service coverage is generally expanding over time.


2-1-1, Availability, Canada
The Windsor Star has reported on March 20, 2003 that Windsor, Ontario intended to have a 2-1-1 service up by 2009, as the Provincial Government allocated $311,000 to start it up, with much of the money being donated by the United Way of Canada, but had a set time limit on how long those funds would be available. On November 26, 2007, the City of Windsor's  announced that 2-1-1 service for Windsor and Essex County began, and was being run by the United Way (who also runs the local 3-1-1 service).


2-1-1, Availability, Canada
Plans to introduce 2-1-1 services are also in development in other Canadian communities. Ontario extended 2-1-1 province-wide in 2012 and Nova Scotia's province-wide 2-1-1 deployment will be fully operational in 2014. In British Columbia, 2-1-1 services are administered by , and is available on Vancouver Island\Gulf Islands and in the Metro Vancouver, Squamish-Lillooet, Sunshine Coast Regional District and Fraser Valley and regional districts, with plans to expand the services provincially.


2-1-1, Availability, Canada
In some communities, unused X-1-1 codes were assigned as plant test numbers for telephone installers testing individual lines. In the Canadian province of Prince Edward Island, for instance, when 2-1-1 was dialed, it caused a busy signal to occur and the dialer's telephone line would "go dead" for several minutes afterward. These codes must first be "recovered" by moving the test functions elsewhere (958 and 959 are standard reserved local and long-distance test exchanges in most areas) to permit redeployment as local public information numbers.


2-1-1, Accreditation, United States
The American accrediting body for 2-1-1 centers is the  (AIRS). AIRS provides an in-depth accreditation process for 2-1-1 centers. AIRS also certifies 2-1-1 Call Center Representatives as Certified Information and Referral Specialists (CIRS), Certified Information and Referral Specialists for Aging (CIRS-A) and Certified Resource Specialists (CRS) annually. AIRS standards have been created to provide a benchmark for 2-1-1 centers and its staff. The standards regulate nationally how a 2-1-1 centers provides services and how they collect and store information.


2-1-1, Accreditation, United States
INFOLINE of Los Angeles, an information and referral services agency serving the greater Los Angeles area, developed a national taxonomy of human services that provides a standard language for information and referral providers nationally. AIRS adopted this taxonomy as its national standard for use in the field of information and referral. This taxonomy provides standard definition of terms, an exact coding structure for referrals and search methodology for providing referrals to consumers. More information about the AIRS/Infoline Taxonomy of Human Services can be found at .


2-1-1, Accreditation, United States
Accredited 2-1-1 centers must have active Memorandums of Understanding with local 9-1-1 service as well as domestic violence providers, elder care providers, mental health providers and local law enforcement to name a few.


2-1-1, Accreditation, Canada
In Canada, professional certification is handled by InformCanada . The national 211 initiative is a partnership between InformCanada and United Way of Canada – Centraide Canada.


2-1-1, Accreditation, Canada
Work is underway to create a bilingual, Canadian Taxonomy of human services based on the AIRS/Infoline Taxonomy. This project is led by InformCanada and significant steps have been made on the creation of a starter taxonomy by the 211 Ontario phase 2 project, funded by the Ontario Trillium Foundation and the government of Canada. Updates on the Canadian Taxonomy Project are maintained by 211.ca.


2-1-1, Implementation process
The number 2-1-1 must be captured and approved for assigning through the local telecom companies providing services in the local area. The process of implementing a 2-1-1 service in a community has taken many paths since its beginning in 1997. Some places have a centralized statewide system while others have decentralized regional networks with different types of affiliations.


2-1-1, Implementation process
In the United States, each implementation is monitored by the national accrediting entity  (AIRS) and its local statewide affiliate.


2-1-1, Implementation process
In Canada, the deployment of 2-1-1 service is subject to InformCanada accreditation and Canadian Radio-television and Telecommunications Commission (CRTC) approval.


2-1-2 Forecheck
The 2-1-2 forecheck, or pinch on a wide rim is an ice hockey forechecking strategy which uses two forwards deep in the offensive zone, with the remaining forward positioned high in the offensive zone, and the two defencemen positioned at the highest part of the zone near the blue line. This forecheck is used to apply both mental and physical pressure on the opposing team as they try to move the puck out of their defensive zone with objective of forcing a turnover. The positioning of the players removes options for moving the puck along the boards, forcing the play to the middle.


2-1-2 Forecheck
Each of the five skaters has a specific role in the execution of the 2-1-2 forecheck.


2-1-2 Forecheck
This system of forechecking needs to have good skaters in order to be successful. The Edmonton Oilers during their dynasty years were such a club and made use of the 2-1-2 forecheck.


2-10-0
Under the Whyte notation for the classification of steam locomotives, 2-10-0 represents the wheel arrangement of two leading wheels on one axle, ten powered and coupled driving wheels on five axles, and no trailing wheels. This arrangement was often named Decapod, especially in the United States, although this name was sometimes applied to locomotives of 0-10-0 "Ten-Coupled" arrangement, particularly in the United Kingdom. Notable German locomotives of this type include the war locomotives of Class 52.


2-10-0
These locomotives were popular in Europe, particularly in Germany and Russia; British use of the type was confined to the period during and after World War II. In the United States, the 2-10-0 was not widely popular but was a favorite of a small number of railroads which operated mostly in mountainous terrain. Among these was the Erie Railroad, a major Chicago to New York trunk line railroad.


2-10-0
The 2-10-0's main advantage was that five out of six of its axles were powered, meaning almost all the weight was available for traction rather than being distributed over pilot and trailing wheels. The long rigid wheelbase caused problems on tightly curved track, so blind drivers were the norm, either on the central axle, and/or on the second and/or fourth axles. Often lateral motion devices were attached to the leading drive axle.


2-10-0
The wheel arrangement's disadvantages included the firebox size restriction caused by the lack of trailing wheel. This meant the firebox was fitted in between the wheels (common on earlier locomotives) and was long and narrow, or if mounted above the driving wheels, was wide and long but shallow. Many locomotives chose the latter option. A firebox mounted over the drivers also restricted the diameter of the driving wheels, which in turn limited speed. As with the Consolidation (2-8-0), "chopping" at speed ensured a rough ride for the crew due to instability caused by the wheel arrangement. In fact, backing any locomotive without a trailing axle was restricted to under twenty miles per hour or less. Most 2-10-0s were not operated at speeds greater than 50 mph (80 km/h).


2-10-0
The type operated as freight engine, although locomotives in Germany and the United Kingdom proved capable of hauling passenger trains.


2-10-0, United States
The first Decapods were built for the Lehigh Valley Railroad in the late-1860s. They proved too rough on the track because of their long coupled wheelbase. No more followed for 19 years, until the Northern Pacific Railway bought two for use on the switchbacks over Stampede Pass, while the 2-mile (3.2 km) tunnel was being built. In low-speed service where high tractive effort was critical, these Decapods were successful. Small numbers of other Decapods were built over the next twenty years, mostly for service in steeply graded mountainous areas where power at low speeds was the requirement. The type did not prove as popular as the successful Consolidation (2-8-0) type. Among Decapod users was the Atchison, Topeka and Santa Fe Railway. The engines were tandem compounds but their ongoing reversing limitations became the genesis of the 2-10-2 wheel arrangement.


2-10-0, United States
The first boost in the number of Decapods occurred when Imperial Russia ordered approximately 1,200 Decapods from American builders during World War I. When the Bolshevik revolution occurred in 1917, 857 had already been delivered, but more than 200 were either awaiting shipment or were in the process of construction. These stranded locomotives were adopted by the United States Railroad Administration (USRA), the body created by the Government to oversee and control the railroads during the War, converted to American standards, and put to use on American railroads. Small and light-footed, these Russian decapods proved popular with smaller railroads, and many of them remained in service long after the USRA's control of the railroads ceased. Many indeed lasted until the end of steam on those railroads.


2-10-0, United States
Swengel suggested the 2-10-0 arrangement was 'obsolete' by 1916, when the Pennsylvania Railroad (PRR) commenced an experiment with a 2-10-0 locomotive at its Juniata plant. Most 10 coupled engines constructed for U.S. railroads during World War I were of the USRA 2-10-2 arrangement, but the PRR committed to 122 of the 2-10-0s. Swengel argued this commitment to the 2-10-0, nicknamed "Deks", was controversial even in 1916 and was more so in 1922 when the PRR placed additional orders. The PRR was soon the biggest user of Decapods in the United States. The type was ideally suited to the Pennsy's heavily graded Allegheny Mountains routes, which required lugging ability according to tractive effort, not speed according to horse power.


2-10-0, United States
The PRR bought 598 2-10-0s including 123 built at its own shops. In one of the largest locomotive orders ever, the rest came from the Baldwin Locomotive Works. The PRR 2-10-0s weighed 386,100 lb (175.1 t) and developed about 90,000 lbf (400.3 kN) of tractive effort with an axle loading of over 70,000 lb (32 t). The engines steamed at 250 psi (1.72 MPa) and had a relatively large superheater. The grate area of about 70 sq ft (6.5 m2) was on the small side, but a mechanical stoker partly compensated for this.


2-10-0, United States
The PRR decapod, class I1s, was unlike the Russian decapod; it was huge, taking advantage of the PRR's heavy trackage and high axle loading, with a fat, free-steaming boiler that earned the type the nickname of 'Hippos' on the PRR. Two giant cylinders (30½ x 32 inch) gave the I1s power and their tenders permitted hard and long workings between stops. They were unpopular with the crews, for they were hard riding. The last operations on the PRR were 1957.


2-10-0, United States
A small number of other Decapods were ordered by other railroads; the I-2 Decapods built for the Western Maryland Railway were the largest ever built, at almost 420,000 lb (190 t) weight, and are a notable exception to the rule of thumb for the comfort of the ride on a 2-10-0 wheel arrangement, crews said the engines cruised smoothly up to 50 mph without becoming a rough ride. (After the running gear was redesigned by the WM) The WM's I-2 are also noted as the strongest Decapods ever built, at 96,315 lbs of tractive effort.


2-10-0, United States
(Not to be confused with the 10 Russian Decapods the WM held in their roster, which were standard Russian Decapods aside from heavier steel frames the WM used to replace the original cast iron frames, the new frames also made the WM Russian Decapods 2 inches longer than other Russian Decapods)


2-10-0, United States
Baldwin developed two standard 2-10-0s for railroads with low axle-load requirements.


2-10-0, United States
Thirteen Decapod locomotives survive in the US, including two Baldwin standards, six Russian Decapods and one PRR I1. Two, Great Western 90, a Baldwin Decapod at the Strasburg Rail Road, and Frisco 1630, a Russian Decapod at the Illinois Railway Museum, are operational. One Decapod survives as a static exhibit at the North Carolina Transportation Museum in Spencer, North Carolina (Seaboard Air Line 2-10-0 #544).


2-10-0, Germany
The 2-10-0 arrangement was a very popular one in Germany. The first were built by the individual state railways from 1915 to 1918, and these later became the DRG BR58. The DRG then produced a number of standard classes of 2-10-0s: the heavy 3-cylinder BR44 (1753 built), the two-cylinder version BR43 (35 built), and the lightweight BR50 (3164 built). During wartime, the BR44 and BR50 designs were simplified as ÜK (Übergangs Kriegslokomotiven, or interim war locomotives). By 1941, it was clear that even these were too complicated, expensive, time-consuming to build, and used too much material in short supply, so new Kriegslokomotive (war locomotive) designs were developed: the lightweight BR52 (7794 built) and the intermediate weight BR42 (859 built).


2-10-0, Germany
Postwar locomotives of these types, particularly the BR 52, were spread all over Europe and were taken into service by the railways of many different countries:


2-10-0, United Kingdom
Locomotives with ten driving wheels were rare in British railway history. In 1913 an initial design for a four-cylinder 2-10-0 of 53,328 pounds-force (237,000 N) tractive effort was produced by the Lancashire and Yorkshire Railway, but none were built. This had been inspired by Jean-Baptiste Flamme's Type 36 (SNCB) 2-10-0s working in Belgium and used a similar tapered boiler, with the round-topped firebox almost filling the loading gauge. The first 2-10-0 was built during the Second World War, as a variant of the "Austerity" 2-8-0 for lightly built railways.


2-10-0, United Kingdom
The only other 2-10-0 type was the 251-strong Standard class 9F introduced by British Railways in 1954. The class included 92220 Evening Star, the last steam locomotive built for British Railways, in 1960; and 92203 (named Black Prince when preserved), which in 1983 set a record for the heaviest steam locomotive-hauled train in Britain when it started a 2,162-ton train at Foster Yeoman quarry in Somerset.


2-10-0, Finland
The State Railroads of Finland purchased 20 American Decapods after WWII - these were originally built for the Soviet Union, but never delivered to them. Of the 20 engines, 10 were made by Baldwin, 10 by Alco. Since they were originally built for the USSR, they had the correct gauge for Finland, too (1,524 mm (5 ft) exactly). One (Alco # 75214, 1947) is preserved at the Finnish Railway Museum in Hyvinkää, Finland. The Finnish designation was Tr2.


2-10-0, Finland
The locomotive was nicknamed Truman in Finland. It was used for hauling heavy freight trains.


2-10-0, France
From 1910 to 1951, the French industry built more than 500 decapods for three railway companies (Paris-Orléans, Nord, Est) and for the national railways (SNCF). Moreover, at the end of World War II, SNCF inherited more than 200 units of German decapods built in France, mostly BR 44. The last decapod, a SNCF 150P, was withdrawn in 1968. All 2-10-0s, of French or of German design, proved reliable and powerful in service. One can notice that some engines of the Paris-Orléans company were dedicated to passenger service on difficult mountain lines.


2-10-0, Poland
Between early 1920s and 1958 Polish industry delivered to PKP some 1200 decapods of classes Ty23, Ty37, Ty45 and Ty51. PKP also operated German decapods BR 52 (Ty2) and BR 42 (Ty3), as well as American ones (Ty246, nicknamed "Trumman"). They were used to work the heaviest goods trains.


2-10-0, Romania
After the Second World War, Romania built the 150.000 Class, after DRB Class 50. A total of 282 locomotives were built between 1946 and 1960, at Malaxa (later 23 August Works) in Bucharest, and in Reşiţa.


2-10-0, Soviet Union
2-10-0 were fairly common freight locomotives in the former Soviet Union. They came from several sources: US imports (class Ye (Russian: серия Е), built by ALCO and Baldwin, respectively), German war trophy DRB 52 class locomotives (what became the Soviet TE-series) and locally built. The locally built 2-10-0 locomotives were represented by some TE (built from captured German parts), SO (Sergo Ordjonikidze) and L (Lebedyanski)–series locomotives. The L-series locomotives were one of the more advanced steam locomotives built in the former Soviet Union. They used an automatic stoker to feed coal and had a relatively low axle load (18 tonnes or 40,000 lb) to be compatible with the war-torn railroads of the former Soviet Union. Several examples of these locomotives are still preserved in working order.


2-10-0, Soviet Union
There is a 2-10-0 Lebedyanski series locomotive L 4657, marooned in a siding at Port Baikal.


2-10-10-2
Under the Whyte notation for the classification of steam locomotive wheel arrangements, a 2-10-10-2 is a locomotive with two leading wheels, two sets of ten driving wheels, and a pair of trailing wheels.


2-10-10-2
The equivalent UIC classification is refined to (1′E)E1′ for Mallet locomotives. All 2-10-10-2 locomotives have been articulated locomotives, Mallet locomotives in particular.


2-10-10-2
This wheel arrangement was rare. Only two classes of 2-10-10-2 locomotives have been built; the Atchison, Topeka and Santa Fe Railway's 3000 class, and the Virginian Railway's class AE. The Atchison, Topeka, and Santa Fe 3000 class unfortunately performed poorly, and therefore were rebuilt back to the original 2-10-2s they came from between 1915-1918, after only being in service for approximately 3-7 years. None of these survived into preservation. The Virginian Railway Class AE were much more successful, providing between 25-31 years of service, where some were scrapped from 1943-1945, and the rest were scrapped from 1947 to 1949 . None were preserved.


2-10-10-2, ATSF 3000 class
This class of ten 2-10-10-2 locomotives were actually rebuilt from more conventional 2-10-2 Baldwin-built locomotives by the Atchison, Topeka and Santa Fe Railway in 1911 to 1912.


2-10-10-2, ATSF 3000 class
The ATSF 2-10-10-2's, #3000 class locomotives, were the largest locomotives in the world from 1911 to 1914.


2-10-10-2, ATSF 3000 class
Despite being good for helper service, they could only go 10 to 15mph before losing steam, resulting in the locomotives being rebuilt to 2-10-2s during 1915–1918.


2-10-10-2, Virginian Railway class AE86
These ten locomotives were built in 1918 by ALCO for the Virginian Railway. With a width of 144 inches (3,658 mm), they were delivered without their cabs and front low-pressure cylinders; and were assembled after delivery. The 48-inch (1,219 mm) low-pressure cylinders (on 90-inch or 2,286-millimetre centers) were the largest on any US locomotive; the cylinders had to be inclined a few degrees to provide clearance. The boiler was also the largest diameter of any locomotive; Railway Mech Engnr says "the outside diameter of the largest course is 112+7⁄8 inches (2,867 mm)." but the drawing shows 118+1⁄2 inches (3,010 mm) diameter at the rear tube sheet. The size of the fuel tenders was short so the locomotive would fit on the Virginian's existing turntables.


2-10-10-2, Virginian Railway class AE86
This class were compound Mallet locomotives. The rear, high-pressure cylinders exhausted their steam into the huge front cylinders. They could also be operated in simple mode for starting; reduced-pressure steam could be sent straight from the boiler to the front cylinders at low speed, for maximum tractive effort.


2-10-10-2, Virginian Railway class AE86
The calculated tractive effort was 147,200 lb (66,800 kg) in  compound; or 176,600 lb (80,100 kg) in simple for the Virginian locomotives.


2-10-10-2, Virginian Railway class AE86
The class remained in service until the 1940s. No locomotive example of this type survived into preservation.


2-10-2
Under the Whyte notation for the classification of steam locomotives, 2-10-2 represents the wheel arrangement of two leading wheels, ten powered and coupled driving wheels, and two trailing wheels. In the United States of America and elsewhere the 2-10-2 is known as the Santa Fe type, after the Atchison, Topeka and Santa Fe Railway that first used the type in 1903.


2-10-2, Overview
The 2-10-2 wheel arrangement evolved in the United States from the 2-10-0 Decapod of the Atchison, Topeka and Santa Fe Railway (ATSF). Their existing 2-10-0 tandem compound locomotives, used as pushers up Raton Pass, encountered problems reversing back down the grade for their next assignments since they were unable to track around curves at speed in reverse and had to run very slowly to avoid derailing. Consequently, the ATSF added a trailing truck to the locomotives which allowed them to operate successfully in both directions. These first 2-10-2 locomotives became the forerunners to the entire 2-10-2 family.


2-10-2, Overview
The trailing truck allows a larger, deeper firebox than that of a 2-10-0. Like all ten-coupled designs, the long rigid wheelbase of the coupled wheels presented a problem on curves, requiring flangeless drivers, lateral motion devices and much sideplay on the outer axles. To limit this problem, the coupled wheels were generally small, up to 64 inches (1,630 millimetres) in diameter, which in turn generated the problem of insufficient counterweights to balance the weight of the driving rods.


2-10-2, Overview
The 2-10-2's inherent problem was the low speed restriction on the type, which was about 35 miles per hour (56 kilometres per hour). Further, the 2-10-2 had other inherent restrictions. The massive cylinders that were required on locomotives in the United States for high tractive effort had the result that no reasonably sized valves could admit and exhaust steam at a sufficient rate to permit fast running.


2-10-2, Overview
In addition the 2-10-2, like the 2-6-2, had its main rod connected to the middle coupled axle, very near to the centre of gravity, which created a violent nosing (waddling) action when operating at speed. The peak of the 2-10-2 design limitations was reached in the United States in 1926 and was overcome with the advent of the superior 2-10-4 design.


2-10-2, Usage
Locomotives with a 2-10-2 wheel arrangement were used in a number of countries around the world, including those in North America, Western Europe, China, the Soviet Union and Africa. Continental Europe saw a fair number of 2-10-2s, although the type was always less popular than 2-8-2 Mikados and 2-10-0 Decapods. A large number of European 2-10-2s were tank locomotives, taking advantage of the symmetrical nature of the wheel arrangement.


2-10-2, Usage, Argentina
The metre gauge General Manuel Belgrano Railway in Argentina operated the E2 series of 2-10-2 locomotives. In 1956, Mitsubishi Heavy Industries of Japan constructed a batch of ten 2-10-2s based on this design for the isolated Ramal Ferro Industrial Río Turbio (RFIRP) 750 mm gauge railway in the southern Patagonian Desert, to haul coal from Río Turbio for shipping from Río Gallegos, Santa Cruz. These required modification by Livio Dante Porta to achieve their full potential. Ten more powerful examples were introduced into service in 1964.


2-10-2, Usage, Belgian Congo
Two classes of 2-10-2 locomotives were used in the Belgian Congo.


2-10-2, Usage, Canada
In 1916, Canadian National Railways (CNR) took delivery of ten Class T-1-a 2-10-2s from an order made by the short-lived Canadian Government Railways and built by ALCO. Ten more were delivered from the Montreal Locomotive Works in 1918, and another 25 slightly modified T-1-cs in 1920 that were 1,100 pounds lighter. Canadian Locomotive Company produced five T-2-as in 1924. Ten ALCO's named "T-3-a" were acquired from the Boston and Albany Railroad in 1928. Canadian Locomotive Company produced the last series of 2-10-2s for CNR, a batch of 15 T-4-as in 1929, and 18 T-4-bs in 1930.


2-10-2, Usage, Canada
The 2-10-2s began to be scrapped in the mid-1950s, with the last models being used until 1961. There are two surviving CNR 2-10-2 locomotives. One is No. 4008, on display at the CNR Station in Rainy River, Ontario, and the other is No. 4100, on display at the Canadian Railway Museum in Delson, QC.


2-10-2, Usage, China
The mainstay of Chinese steam was their 2-10-2 locomotives. This was the wheel arrangement of the Chinese QJ class locomotives that were based on the Soviet LV class and built by Datong Locomotive Works from 1959. They were produced until 1988 and were still in widespread service until the final steam runs in 2005.


2-10-2, Usage, China
After retirement, some of these QJ class locomotives found their way to the United States, where they are used in revenue freight and excursion service. In Train Festival 2011, Multipower International restored two Chinese IAIS 6988 locomotives to Federal Railroad Administration (FRA) Part 230 specifications and delivered them to the Railroad Development Corporation.


2-10-2, Usage, Germany
Examples on the German railway systems included classes BR84 and BR85, both standard tank locomotive designs built in 1935 and 1937 respectively, and class BR95, a tank locomotive built in 1922 by the Prussian State Railways as the Prussian T 20.


2-10-2, Usage, Germany
From 1936, the German railways built 28 three-cylinder 2-10-2 tender freight locomotives of class BR45, which were the most powerful steam locomotives on the system.


2-10-2, Usage, Germany
Further examples, still in regular service, are the metre-gauge DR Class 99.23-24 on the Harz Narrow Gauge Railways and the 750 mm-gauge DR Class 99.77-79 on the Rügen narrow-gauge railway.


2-10-2, Usage, Mozambique
While the 2-10-2 wheel arrangement was not very common in Africa, the Lourenco Marques system in Mozambique (Caminhos de Ferro de Moçambique or CFM) had altogether 37 locomotives of this type, in three classes.


2-10-2, Usage, Philippines
The Manila Railroad Company (now the Philippine National Railways) acquired ten 200-class locomotives in 1922 from the American Locomotive Company (Alco) and was purchased alongside the 4-8-2 170-class. Based on Henry Kirke Porter's acclaimed design of the 45 class, these were intended to replace the original Scottish-built tank locomotives as well as a small group of 4-4-2 tender locomotives that were acquired from the company's predecessors.


2-10-2, Usage, Philippines
They were serviced to haul heavy freight trains on the South Main Line between Manila and Lucena. This class also had one of the largest cylinders of any unarticulated Cape-gauge locomotive according to Alco, but it comparatively had small boilers and grills. Their arrival also called for larger 80 feet (24 m) turntables in both ends of the line, making them some of the largest and most powerful locomotives that entered Philippine service.


2-10-2, Usage, Philippines
Out of ten locomotives, four managed to survive World War II, all of which were still in active service in 1952. However, these locomotives were retired after the MRR turned to upgrading its fleet to diesel locomotives in 1956. Not a single unit was preserved.


2-10-2, Usage, Poland
Twenty-five OKz32 2-10-2 tank locomotives were delivered to PKP between 1934 and 1936. They were used mainly to work passenger trains between Kraków and Zakopane, a difficult railway line, steep in places, with many sharp curves, and requiring three direction changes.


2-10-2, Usage, Romania
Romania designed its 151.000 Class as freight locomotives to serve on the Căile Ferate Române (CFR). These locomotives used a straightforward two-cylinder 650 by 720 millimetres (25.591 by 28.346 inches) engine with 1,500 millimetres (59 inches) diameter coupled wheels and a total weight in working order of 123 tonnes (121 long tons; 136 short tons). The heating surface of the boiler was 254.8 square metres (2,743 square feet), of which 98.5 square metres (1,060 square feet) were superheated, while the grate area was 4.72 square metres (50.8 square feet). At a tractive effort of 21,294 kilograms-force (208,820 newtons; 46,950 pounds-force), they were the most powerful steam locomotives built in Romania.


2-10-2, Usage, Romania
Two of these locomotives were built by the Malaxa Works in 1939 and 1941, numbered 151.001 and 151.002. Number 151.002 was preserved.


2-10-2, Usage, South Africa
On 3 ft 6 in (1,067 mm) Cape gauge, this wheel arrangement was first used by the South African Railways (SAR) in 1927. Two Class 18 steam locomotives, the most powerful non-articulated locomotives to see service on the SAR, were introduced on the line between Witbank and Germiston in an attempt to ease problems that were being experienced with increasingly heavy coal trains. It was designed by Colonel F.R. Collins DSO, Chief Mechanical Engineer of the SAR from 1922 to 1929, and built by Henschel and Son in Germany. They were three-cylinder locomotives, with the two outer cylinders using Walschaerts valve gear and the inner cylinder using Gresley conjugated valve gear, actuated by the motions of the outer cylinders.


2-10-2, Usage, South Africa
One more 2-10-2 locomotive, the Class 20, was designed for branch line work on light rail by A.G. Watson, Chief Mechanical Engineer from 1929 to 1936. Only one locomotive was built by the SAR at its Pretoria Mechanical Shops at Salvokop in 1935.


2-10-2, Usage, South Africa
In 1950, this sole Class 20 locomotive was modified to an experimental condensing locomotive, equipped with a condensing tender that was ordered from Henschel in Germany in 1948. Beginning in 1951, tests with the condensing Class 20 were conducted in the Eastern Transvaal and the Karoo. The positive results of the condensing trials proved the viability of condensing locomotives in South Africa and led to the introduction of the Class 25 4-8-4 condensing locomotive fleet in 1953.


2-10-2, Usage, Soviet Union
In the Soviet Union, 2-10-2 locomotives were used to haul heavy freight trains. Two series were relatively common, the FD (for Felix Dzerzhinsky) with more than three thousand built through the 1930s, and the LV (Lebedyanskii, modified by the Voroshilovgrad factory).


2-10-2, Usage, Soviet Union
The FD class was developed from ALCO and Baldwin heavy freight locomotives that were imported to Soviet Russia, where they were designated as the Ta and Tb classes respectively. The first FD class locomotive was built at the Lugansk Locomotive Factory in 1931.


2-10-2, Usage, Soviet Union
In 1932, the Voroshilovgradskom plant began with the mass production of ФД20 locomotives. In the process of production, their construction was improved constantly. Production was interrupted at the outbreak of the Great Patriotic war in 1941 and was only resumed in 1942, when four locomotives were built in Ulan Ude. The total production was 2,927 locomotives of ФД20, and 286 locomotives of ФД21. The two subclasses only differed in respect of their types of superheater.


2-10-2, Usage, Soviet Union
In 1958, 1,054 FD class locomotives were sold to China, where they worked until the 1980s. A much lesser number were sold to North Korea at around the same time.