Niacinamide or nicotinamide is a form of vitamin B3 found in food and used as a dietary supplement and medication. As a supplement, it is used orally (swallowed by mouth) to prevent and treat pellagra (niacin deficiency). While nicotinic acid (niacin) may be used for this purpose, niacinamide has the benefit of not causing skin flushing. As a cream, it is used to treat acne, and has been observed in clinical studies to improve the appearance of aging skin by reducing hyperpigmentation and redness. It is a water-soluble vitamin. Niacinamide is the supplement name, while nicotinamide is the scientific name.
Pyridine is a basic heterocyclic organic compound with the chemical formula C5H5N. It is structurally related to benzene, with one methine group (=CH−) replaced by a nitrogen atom (=N−). It is a highly flammable, weakly alkaline, water-miscible liquid with a distinctive, unpleasant fish-like smell. Pyridine is colorless, but older or impure samples can appear yellow, due to the formation of extended, unsaturated polymeric chains, which show significant electrical conductivity. The pyridine ring occurs in many important compounds, including agrochemicals, pharmaceuticals, and vitamins. Historically, pyridine was produced from coal tar. As of 2016, it is synthesized on the scale of about 20,000 tons per year worldwide.
In organic chemistry, a toluenesulfonyl group (tosyl group, abbreviated Ts or Tos) is a univalent functional group with the chemical formula −SO2−C6H4−CH3. It consists of a tolyl group, −C6H4−CH3, joined to a sulfonyl group, −SO2−, with the open valence on sulfur. This group is usually derived from the compound tosyl chloride, CH3C6H4SO2Cl (abbreviated TsCl), which forms esters and amides of toluenesulfonic acid, CH3C6H4SO2OH (abbreviated TsOH). The para orientation illustrated (p-toluenesulfonyl) is most common, and by convention tosyl without a prefix refers to the p-toluenesulfonyl group.
The Hofmann rearrangement is the organic reaction of a primary amide to a primary amine with one less carbon atom. The reaction involves oxidation of the nitrogen followed by rearrangement of the carbonyl and nitrogen to give an isocyanate intermediate. The reaction can form a wide range of products, including alkyl and aryl amines.
In organic chemistry, the Knoevenagel condensation reaction is a type of chemical reaction named after German chemist Emil Knoevenagel. It is a modification of the aldol condensation.
4-Aminopyridine (4-AP) is an organic compound with the chemical formula H2NC5H4N. It is one of the three isomeric aminopyridines. It is used as a research tool in characterizing subtypes of the potassium channel. It has also been used as a drug, to manage some of the symptoms of multiple sclerosis, and is indicated for symptomatic improvement of walking in adults with several variations of the disease. It was undergoing Phase III clinical trials as of 2008, and the U.S. Food and Drug Administration (FDA) approved the compound on January 22, 2010. Fampridine is also marketed as Ampyra in the United States by Acorda Therapeutics and as Fampyra in the European Union, Canada, and Australia. In Canada, the medication has been approved for use by Health Canada since February 10, 2012.
Dimethylglyoxime is a chemical compound described by the formula CH3C(NOH)C(NOH)CH3. Its abbreviation is dmgH2 for neutral form, and dmgH− for anionic form, where H stands for hydrogen. This colourless solid is the dioxime derivative of the diketone butane-2,3-dione (also known as diacetyl). DmgH2 is used in the analysis of palladium or nickel. Its coordination complexes are of theoretical interest as models for enzymes and as catalysts. Many related ligands can be prepared from other diketones, e.g. benzil.
Allylpalladium(II) chloride dimer (APC) is a chemical compound with the formula [(η3-C3H5)PdCl]2. This yellow air-stable compound is an important catalyst used in organic synthesis. It is one of the most widely used transition metal allyl complexes.
Lithium triethylborohydride is the organoboron compound with the formula LiEt3BH. Commonly referred to as LiTEBH or Superhydride, it is a powerful reducing agent used in organometallic and organic chemistry. It is a colorless or white liquid but is typically marketed and used as a THF solution. The related reducing agent sodium triethylborohydride is commercially available as toluene solutions.
The Chichibabin reaction is a method for producing 2-aminopyridine derivatives by the reaction of pyridine with sodium amide. It was reported by Aleksei Chichibabin in 1914. The following is the overall form of the general reaction:
The Doebner reaction is the chemical reaction of an aniline with an aldehyde and pyruvic acid to form quinoline-4-carboxylic acids.
Pyridine-N-oxide is the heterocyclic compound with the formula C5H5NO. This colourless, hygroscopic solid is the product of the oxidation of pyridine. It was originally prepared using peroxyacids as the oxidising agent. The compound is used infrequently as an oxidizing reagent in organic synthesis.
Trifluoromethanesulfonyl azide or triflyl azideCF3SO2N3 is an organic azide used as a reagent in organic synthesis.
2-Aminopyridine is an organic compound with the formula H2NC5H4N. It is one of three isomeric aminopyridines. It is a colourless solid that is used in the production of the drugs piroxicam, sulfapyridine, tenoxicam, and tripelennamine. It is produced by the reaction of sodium amide with pyridine, the Chichibabin reaction.
Alcohol oxidation is a collection of oxidation reactions in organic chemistry that convert alcohols to aldehydes, ketones, carboxylic acids, and esters. The reaction mainly applies to primary and secondary alcohols. Secondary alcohols form ketones, while primary alcohols form aldehydes or carboxylic acids.
Chloro(pyridine)cobaloxime is a coordination compound containing a CoIII center with octahedral coordination. It has been considered as a model compound of vitamin B12 for studying the properties and mechanism of action of the vitamin. It belongs to a class of bis(dimethylglyoximato)cobalt(III) complexes with different axial ligands, called cobaloximes. Chloro(pyridine)cobaloxime is a yellow-brown powder that is sparingly soluble in most solvents, including water.
Pyridyne in chemistry is the pyridine analogue of benzyne. Pyridynes are the class of reactive intermediates derived from pyridine. Two isomers exist, the 2,3-pyridine (2,3-didehydropyridine) and the 3,4-pyridyne (3,4-didehydropyridine). The reaction of 3-bromo-4-chloropyridine with furan and lithium amalgam gives 1,4-epoxy-dihydroquinoline through the 2,3-pyridyne intermediate. The reaction of 4-bromopyridine with sodium in liquid ammonia gives both 3-aminopyridine and 4-aminopyridine through the 3,4-pyridyne intermediate and an E1cB-elimination reaction.
2-Bromopyridine is an aryl bromide and isomer of bromopyridine with the formula BrC5H4N. It is a colorless liquid that is used as an intermediate in organic synthesis. It can be prepared from 2-aminopyridine via diazotization followed by bromination.
Sodium hypobromite is an inorganic compound with the chemical formula NaOBr. It is a sodium salt of hypobromous acid. It consists of sodium cations Na+ and hypobromite anions −OBr. It is usually obtained as the pentahydrate, so the compound that is usually called sodium hypobromite actually has the formula NaBrO·5H2O. It is a yellow-orange solid that is soluble in water. It adopts a monoclinic crystal structure with a Br–O bond length of 1.820 Å. It is the bromine analogue of sodium hypochlorite, the active ingredient in common bleach. In practice the salt is usually encountered as an aqueous solution.
Pyrithione is the common name of an organosulfur compound with molecular formula C
5H
5NOS, chosen as an abbreviation of pyridinethione, and found in the Persian shallot. It exists as a pair of tautomers, the major form being the thione 1-hydroxy-2(1H)-pyridinethione and the minor form being the thiol 2-mercaptopyridine N-oxide; it crystallises in the thione form. It is usually prepared from either 2-bromopyridine, 2-chloropyridine, or 2-chloropyridine N-oxide, and is commercially available as both the neutral compound and its sodium salt. It is used to prepare zinc pyrithione, which is used primarily to treat dandruff and seborrhoeic dermatitis in medicated shampoos, though is also an anti-fouling agent in paints.
