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Encyclopedia Britannica - Main :: NEW-NUM |
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NICOTINE, C10H ,4N2, an alkaloid, found with small quantities of nicotimine, C19H,4N2, nicoteine, C1oH,2N2, and nicotelline, C10H$N2, in tobacco. The name is taken from Nicotiana, the tobacco plant, so called after Jean Nicot (1530-1600), French ambassador at Lisbon, who introduced tobacco into France in 156o. These four alkaloids exist in combination in tobacco chiefly as malates and citrates. The alkaloid is obtained from an aqueous extract of tobacco by distillation
sharp
taste , and is very poisonous. It is very hygroscopic, dissolves readily in water, and rapidly undergoes oxidation on exposure to air. The free alkaloid is strongly laevo-rotatory. F. Ratz (Monats., 1905, 26, p. 1241) obtained the value [a]u=-169.54 at 20 its salts are dextro-rotatory. It behaves as a di-acid as well as a di-tertiary base.On oxidation with chromic or nitric acids, or potassium permanganate, it yields nicotinic acid or /3-pyridine carboxylic acid, C5H,N'CO2H; alkaline potassium ferricyanide gives nicotyrine, C,oH,0N2, and hydrogen peroxide oxynicotine, C,oH,4N20. Oxidation of its isomethylhydroxide with potassium permanganate yields trigonelline, C7H7NO2 (A. Pictet and P. Genequand, Ber., 1897, 30, p. 2117). It gives rise to various decomposition products such as pyridine, picoline, &c., when its vapour is passed through a red-hot tube. The hydrochloride on heating
sulphruic acid, when an intense rose-red colour is produced (I. Schindelmeiser, Pharm. Zentralhalle, 1899, 40, p. 704). The constitution of nicotine was established by A. Pinner (see papers in the Berichte, 1891 to 1895). With bromine in acetic acid solution at ordinary temperature, nicotine yields a perbromide, C,oH1oBr2N20HBr3, which with sulphur
distillation
heating
caustic
U-CC- CC >NCH3 and CCCN exist in the molecule, and the alkaloid is to be represented as a-pyridyl-N-met hyl-pyrollidi ne. This result has been confirmed by its synthesis by A. Pictet and P. Cr6pieux (Comptes rendus, 1903, 137, p. 86o) and Pictet and Rotschy (Bee., 1904, 37, p. 1225): $-aminopyridine is converted into its mucate, which by dry distillation gives N-/3-pyridylpyrrol. By passing the vapour of this compound through a red-hot tube, it yields the isomeric ai3-pyridylpyrrol; the potassium salt of which with methyl iodide gives a substance methylated both in the pyridine and pyrrol nuclei. By distillation over lime, the methyl group is removed from the pyridine ring, and the resulting a-pyridyl-N-methylpyrrol gives i-nicotine on reduction. This base is resolved into its active components by d-tartaric acid, l-nicotine-d-tartrate crystallizing out first. The natural (laevo) base is twice as toxic as the dextro. The following formulae are important: N CH 1 C =CH CHCH2 0C CH ~/ NH CH l\p N CH2 N / N \// N \/ CH CH H,C CH2 N-0-Pyridylpyrrol, a$-pyridylpyrrol, nicotine. Acetyl and benzoyl derivatives of nicotine on hydrolysis do not yield nicotine, but an isomeric, inactive oily liquid (metanicotine). It is a secondary base, and boils at 275-278 C. Nicotimine is a colourless liquid which boils at 25o-255 C. Its aqueous solution is alkaline. Nicoteine is a liquid which boils at 267 C. It is separated from the other alkaloids of the group by distilling off the nicotine and nicotimine in steam and then fractionating the residue. It is soluble in water and is very poisonous. Nicotelline crystallizes in needles which melt at 147 C. and is readily soluble in hot water. End of Article: NICOTINE, C10H If you wish, you can link directly to this article.
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