Pyridine Sentence Examples

pyridine
  • It gives rise to various decomposition products such as pyridine, picoline, &c., when its vapour is passed through a red-hot tube.

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  • By passing the vapour of this compound through a red-hot tube, it yields the isomeric a0- pyridylpyrrol, the potassium salt of which with methyl iodide gives a substance methylated both in the pyridine and pyrrol nuclei.

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  • By distillation over lime, the methyl group is removed from the pyridine ring, and the resulting a- pyridyl-Nmethylpyrrol gives i-nicotine on reduction.

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  • Rhombic sulphur may be obtained artificially by slowly crystallizing a solution of sulphur in carbon bisulphide, or, better, by exposing pyridine saturated with sulphuretted hydrogen to atmospheric oxidation (Ahrens, Ber., 1890, 23, p. 2708).

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  • Thus benzene, (CH) gives thiophene, (CH) S, from which it is difficultly distinguished; pyridine, (CH) N, gives thiazole, (CH) N S, which is a very similar substance; naphthalene gives thionaphthen, C 11 S, with which it shows great analogies, especially in the derivatives.

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  • Similarly a CH group may be replaced by a nitrogen atom with the production of compounds of similar stability; thus benzene gives pyridine, naphthalene gives quinoline and isoquinoline; anthracene gives acridine and a and 3 anthrapyridines.

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  • Six-membered ring systems can be referred back, in a manner similar to the above, to pyrone, penthiophene and pyridine, the substances containing a ring of five carbon atoms, and an oxygen, sulphur and nitrogen atom respectively.

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  • Pyrrol is readily converted into pyridine derivatives by acting with bromoform, chloroform, or methylene iodide on its potassium salt, t3-brom-and O-chlorpyridine being obtained with the first two compounds, and pyridine itself with the last.

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  • When l-gulonic acid is heated with pyridine, it is converted into l-idonic acid, and vice versa; and d-gulonic acid may in a similar manner be converted into d-idonic acid, from which it is possible to prepare d-idose.

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  • Lastly, when d-galactonic acid is heated with pyridine, it is converted into talonic acid, which is reducible to talose, an isomeride bearing to galactose the same relation that mannose bears to glucose.

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  • The crude anthracene cake is purified by treatment with the higher pyridine bases, the operation being carried out in large steam-jacketed boilers.

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  • The crystallized anthracene is then removed by a centrifugal separator and the process of solution in the pyridine bases is repeated.

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  • The "general" mixture consists of Too litres of spirit, and 5 litres of wood spirit or 2 litre of pyridine.

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  • Konigs, expressed the opinion that the alkaloids were derivatives of pyridine or quinoline.

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  • This view has been fairly well supported by later discoveries; but, in addition to pyridine and quinoline nuclei, alkaloids derived from isoquinoline are known.

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  • The 1 5 diketones of this type, when heated with aqueous ammonia, form pyridine derivatives.

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  • In practice, the crude anthracene is purified by solution in the higher pyridine bases, after which treatment it is frequently sublimed.

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  • Moissan, contains only a trifling amount of morphia, and the effect produced by it is apparently due, not to that alkaloid, but to such decomposition products as pyrrol, acetone and pyridine and hydropyridine bases.

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  • Formulae have been proposed by Pschorr and Knorr explaining this and other decompositions (in Pschorr's formula the morphine ring system is a fusion of a phenanthrene and pyridine nucleus); another formula, containing a fusion of a phenanthrene with a pyrrol ring, was proposed by Bucherer in'1907.

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  • Distilled with zinc dust morphine yields phenanthrene, pyridine and quinoline; dehydration gives, under certain conditions, apomorphine, C17H17N02, a white amorphous substance, readily soluble in alcohol, either and chloroform.

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  • The amount of pyridine produced in most of these processes is very small, and the best source for its preparation is the "light-oil" fraction of the coal-tar distillate.

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  • Pyridine is a colourless liquid of a distinctly unpleasant, penetrating odour.

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  • On the constitution of the pyridine nucleus, see K6rner, Gior.

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  • As regards the isomerism of the pyridine substitution products, three mono-derivatives are known, the different positions being indicated by the Greek, letters a, s and y, as shown in the inset formula.

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  • The oxypyridines may be prepared by distilling the corresponding oxypyridine carboxylic acids with lime, or by fusing the pyridine carboxylic acids with caustic potash.

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  • Hofmann had shown that conine on distillation with zinc dust gave a-propyl pyridine (conyrine).

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  • It also occurs with pyridine and its homologues in bone-oil.

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  • Quinoline is a colourless liquid with a smell resembling that of pyridine.

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  • Alkaline potassium permanganate oxidizes it to pyridine tricarboxylic acid (236).

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  • When reduced in alcoholic solution by means of sodium amalgam it yields methyl granatoline, 08H130H NCH3; this substance, on oxidation with cold potassium permanganate, is converted into granatoline, C 8 H, 5 NO, which on distillation over zinc dust yields pyridine.

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  • The hydrochloride of the latter base when distilled over zinc dust yields a-propyl pyridine.

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  • The aldehydes condense readily with acetoacetic ester in the presence of ammonia, to pyridines (see Pyridine), whilst 0.

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  • Hofmann (see Pyridine).

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  • Thus, axon protection is likely to be mediated by altered ubiquitination or pyridine nucleotide metabolism.

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  • The attachment locant " 4 " in each pyridine amplificant is invariant.

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  • Ladenburg (1883, 1887) demonstrated that the molecule contained a reduced pyridine nucleus.

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  • Contact dermatitis from castor oil and vitamin B was attributed to pyridine derivatives (Kadlec & Hanslian 1965).

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