pyridine

enUK

pyr·i·dine

P0686400 (pĭr′ĭ-dēn′)n. A flammable, colorless or yellowish liquid base, C₅H₅N, having a penetrating odor and serving as the parent compound of many biologically important derivatives. It is used as a solvent and in the manufacture of various agricultural chemicals, rubber products, water repellents, dyes, and drugs.

[pyr(o)- + -id(e) + -ine.]

py·rid′ic (pī-rĭd′ĭk) adj.

pyridine

(ˈpɪrɪˌdiːn) n (Elements & Compounds) a colourless hygroscopic liquid with a characteristic odour. It is a basic heterocyclic compound containing one nitrogen atom and five carbon atoms in its molecules and is used as a solvent and in preparing other organic chemicals. Formula: C5H5N[C19: from pyro- + -id³ + -ine²]

pyr•i•dine

(ˈpɪr ɪˌdin, -dɪn)

n. a colorless, flammable, liquid organic base, C₅H₅N, used chiefly as a solvent and in organic synthesis. [1855; pyr- or pyr (role) + -idine] py•rid•ic (paɪˈrɪd ɪk) adj.

Thesaurus

Noun

pyridine - a toxic colorless flammable liquid organic base with a disagreeable odor; usually derived from coalalkali, base - any of various water-soluble compounds capable of turning litmus blue and reacting with an acid to form a salt and water; "bases include oxides and hydroxides of metals and ammonia"triphosphopyridine - a pyridine ring with three phosphorus groups

pyridine

enUK

pyridine

(pĭr`ĭdēn) or

azine

(ăz`ēn), C₅H₅N, colorless, flammable, toxic liquid with a putrid odor. It melts at −42&degC; and boils at 115.5&degC;. Chemically, it is a heterocyclic aromatic tertiary amine (see under amino groupamino group,
in chemistry, functional group that consists of a nitrogen atom attached by single bonds to hydrogen atoms, alkyl groups, aryl groups, or a combination of these three. An organic compound that contains an amino group is called an amine.
..... Click the link for more information. ). Its molecule resembles that of benzene, one carbon-hydrogen unit in the benzene ring being replaced with a nitrogen molecule. It is miscible with water and with most organic solvents. Its aqueous solution is slightly alkaline. Pyridine is used as a solvent, as a denaturant for alcohol, and as a starting material in the synthesis of other compounds. Compounds that can be derived from pyridine include antihistamines and vitamins. Pyridine is obtained from bone oil or from coal tar by destructive distillation, which decomposes alkaloids that contain it. Alkaloids that contain pyridine include coniine, piperine (the alkaloid in pepper), and nicotine (present in tobacco); free pyridine is present in tobacco smoke.

Pyridine

a heterocyclic compound. Colorless liquid with a characteristic odor. Melting point, — 41.6°C; boiling point, 115.3°C; density, 0.9832 g/cm³ (at 20°C). The structural formula

Pyridine is a weak base that is miscible in all proportions with water and most organic solvents. It forms salts with acids as well as with alkyl halides (RX); the alkyl halide salts are called N-alkyl pyridinium salts and have the general formula C₅H₅N-RX. Pyridine also forms complexes with FeCl₂, S0₂, S0₃, Br₂, and H₂0. It is oxidized by peracids (RCOOOH)to give N-oxides.

Pyridine exhibits the properties of an aromatic compound, although—unlike benzene—it does not undergo electrophilic substitution readily: it is nitrated, sulfonated, and brominated only at about 300°C, primarily with the resultant formation of ss-derivatives. Nucleophilic substitution occurs more easily with pyridine than with benzene. For example, pyridine reacts with NaNH₂ to give α-aminopyridine and with KOH to give a- hydroxypyridine. Pyridine is reduced by sodium in ethanol or by hydrogen over a nickel catalyst at 120°C to give piperidine. The pyridine ring can be cleaved by, for example, the action of bases on pyridinium salts to form glutaconic dialdehyde (HOCCH=CHCH₂COH) or the corresponding glutaconic-dialdehyde derivative. The pyridine nucleus is a structural component of many alkaloids, vitamins, and drugs, including anabasine, nicotine, nicotinic acid, and nikethamide.

Pyridine is toxic, with a maximum permissible vapor concentration in the air of 0.0015 mg/l. Coal tar, which contains about 0.08 percent pyridine, is the major source. A mixture of pyridine and its homologues, the pyridine bases, are extracted with dilute sulfuric acid from the light and medium fractions of the tar oils in coal tar. After neutralization, the desired compounds are separated by distillation.

Pyridine is widely used in industrial organic synthesis as a solvent and in the production of dyes, pesticides, and drugs. Derivatives of pyridine, for example, 2-methyl-5-vinylpyridine, are used in the production of vinylpyridine lattices. Pyridine N-sulfur trioxide (C₅H₅N -S03) is a mild sulfonating agent.

E. P. LUR’E

pyridine

[′pir·ə‚dēn] (organic chemistry) C₅H₅N Organic base; flammable, toxic yellowish liquid, with penetrating aroma and burning taste; soluble in water, alcohol, ether, benzene, and fatty oils; boils at 116°C; used as an alcohol denaturant, solvent, in paints, medicine, and textile dyeing.

pyridine

pyr·i·dine

pyridine

pyr•i•dine

pyridine

pyridine

azine

Pyridine

pyridine

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pyridine

pyr·i·dine

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pyridine

Words related to pyridine

noun a toxic colorless flammable liquid organic base with a disagreeable odor

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