—pyridic /puy rid"ik/, adj./pir"i deen', -din/, n. Chem.a colorless, flammable, liquid organic base, C5H5N, having a disagreeable odor, usually obtained from coal or synthesized from acetaldehyde and ammonia: used chiefly as a solvent and in organic synthesis.[1850-55; PYR- + -ID3 + -INE2]
* * *Any of a class of aromatic compounds with a six-member aromatic ring composed of five carbon atoms and one nitrogen atom, making it a heterocyclic compound.The simplest one is pyridine itself (C5H5N). Natural compounds with pyridine rings include niacin and pyridoxine (see vitamin B complex), the tuberculosis drug isoniazid, and several plant products (e.g., nicotine). Pyridine is used as a raw material for various drugs, vitamins, and fungicides and as a solvent. Because it has a nauseating odour and a burning taste, it is added to ethanol and antifreezes to make them undrinkable (see denaturation).
* * *any of a class of organic compounds of the aromatic heterocyclic series characterized by a six-membered ring structure composed of five carbon atoms and one nitrogen atom. The simplest member of the pyridine family is pyridine itself, a compound with molecular formula C5H5N.Pyridine is used as a solvent and is added to ethyl alcohol to make it unfit for drinking. It is converted to such products as sulfapyridine, a drug active against bacterial and viral infections; pyribenzamine and pyrilamine, used as antihistaminic drugs; piperidine, used in rubber processing and as a chemical raw material; and water repellents, bactericides, and herbicides. Compounds not made from pyridine but containing its ring structure include niacin and pyridoxal, both B vitamins; isoniazid, an antitubercular drug; and nicotine and several other nitrogenous plant products.Pyridine occurs in coal tar, its principal source before development of a synthesis based on acetaldehyde and ammonia. The pure substance is a colourless, flammable, weakly alkaline, water-soluble liquid with an unpleasant odour; it boils at 115.5° C (234° F).
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