I agree Our site saves small pieces of text information (cookies) on your device in order to deliver better content and for statistical purposes. You can disable the usage of cookies by changing the settings of your browser. By browsing our website without changing the browser settings you grant us permission to store that information on your device.
Pyridines (azabenzenes) are six-membered aromatic heterocycles with one nitrogen atom in the ring. Electrophilic substitution with pyridine takes place under severe conditions, predominantly at the 3-position. Pyridine behaves both as a tertiary amine (alkylation, acylation, and N-oxidation), and as an aromatic compound (nucleophilic substitutions at the 2-position). Generally pyridine is much less basic than alkylamines and more basic than pyrrole and aniline. However, it is a sufficiently strong enough base to form salts with mineral acids.
Pyridine and picolines are employed as bases, scavengers, catalysts, as well as solvents for chemical reactions. Pyridine derivatives, 4-dimethylaminopyridine (DMAP) and 4-(1-pyrrolidinyl)pyridine, are best suited to activate the carboxylic acid halides, or anhydrides, during esterifications and acylations, and for alkylations, silylations, polymerizations, and rearrangements.
The Cornforth reagent (pyridinium dichromate, PDC), pyridinium chlorochromate (PCC), and the Collins reagent (adduct of pyridine with CrO3) are some of the most efficient agents for oxidizing alcohols to carbonyl compounds. Pyridine-borane serves as a mild reducing agent and pyridine-SO3 as a sulfonation agent. Pyridine derivatives are extensively employed in coordination chemistry as ligands. Pyridines, aminopyridines, and many other derivatives are precursors for several agrochemicals and pharmaceuticals such as: veterinary antibacterials (sulfasalazine), antiseptic products (cetylpyridinium and laurylpyridinium), antihistamines, and anti-inflammatory agents (for a review on pyridines: Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) pp 1-33).