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CONINE

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Originally appearing in Volume V06, Page 942 of the 1911 Encyclopedia Britannica.
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CONINE , or CoNIINE (a-propyl piperidine), CRH17N, an See also:

alkaloid occurring, associated with y-coniceine, conhydrine, pseudoconhydrine and methyl conine, in See also:hemlock (Conium maculatum). It is a colourless oily liquid of specific gravity o•845 (20° C.), boiling at 166° C., almost insoluble in See also:water, soluble in See also:ether and in See also:alcohol. It has a See also:sharp burning See also:taste and a penetrating See also:smell, and acts as a violent See also:poison. It is dextro-rotatory. The alkaloid is a strong See also:base and is very readily oxidized; chromic See also:acid converts it into normal butyric acid and See also:ammonia; See also:hydrogen peroxide gives aminopropylvalerylaldehyde, NH2•CH(C3H7)•(See also:CH2)3•CHO, whilst the benzoyl derivative is oxidized by See also:potassium permanganate to benzoyl-a-aminovaleric acid, C6H5CO•NH• CH(C3H7) • (CH2)3• COOH. It combines directly with methyl iodide to See also:form dimethyl coninium iodide, C1oH22NI, which by the destructive methylation See also:process of A. W. See also:Hofmann (Berichte, 1881, 14, pp. 494, 659) is converted into the See also:hydrocarbon conylene C8H14, a See also:compound that can also be obtained by See also:heating nitrosoconine with phosphoric anhydride to 8o-90 C. On heating conine with concentrated hydriodic acid and See also:phosphorus it is decomposed into ammonia and normal octane C8H18. Conine is a secondary base, forming a nitroso derivative with nitrous acid, a See also:urethane with chlorcarbonic ester and a See also:tertiary base (methyl conine) with methyl iodide; reactions which point to the presence of the = NH See also:group in the See also:molecule. It was the first alkaloid to be synthesized, a result due to A.

Ladenburg (see various papers in the Bericlate for the years 1881, 1884, 1885, 1886, 1889, 1893, 1894, 1895, and See also:

Liebig's Annalen for 1888, 1894). A. W. Hofmann had shown that conine on See also:distillation with See also:zinc dust gave a-propyl See also:pyridine (conyrine). This substance when heated with hydriodic acid to 3oc C. is converted into a-propyl piperidine, which can also be obtained by the reduction of a-allyl pyridine (formed from a-methyl pyridine and See also:paraldehyde). The a-propyl piperidine so obtained is the inactive (racemic) form of conine, and it can be resolved into the dextro- and laevo-varieties by means of dextro-tartaric acid, the d-conine d-tartrate with See also:caustic soda giving d-conine closely resembling the naturally occurring alkaloid. A. Laden-See also:burg (Ber. 1906, 39, p. 2486) showed that the difference in the rotations of the natural and synthetic d-conine is not due to another substance, iso-conine, as was originally supposed, but that the artificial product is a stereo-isomer, which yields natural conine on heating for some See also:time to 290°-300°, and then distilling. y-Coniceine, CsH15N, is a tetrahydro conyrine, i.e. a tetra-hydro propyl pyridine. It may be obtained by brominating conine, and then removing the elements of hydrobromic acid with alkalis.

Other coniceines have been prepared. Conhydrine, C8H17NO, and pseudoconhydrine are probably stereo-isomers, the latter being converted into the former when boiled with ligroin. Since conhydrine is dehydrated by phosphorus pentoxide into a mixture of a and (3 coniceines, it may be considered an oxyconine. Methyl conine, C5H18N or C3H14•N(See also:

CH3), is synthesized from conine and an aqueous See also:solution of potassium methyl sulphate at Too°.

End of Article: CONINE

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