Piperine, conine, atropine, belladonine, cocaine, hyoscyamine and nicotine have been already synthesized; the constitution of several others requires confirmation, while there remain many important alkaloids - quinine, morphine, strychnine, &c. - whose constitution remains unknown.
(1) Pyridine group. Piperine; conine; trigonelline; arecaidine; guvacine; pilocarpine; cytisine; nicotine; sparteine.
CONINE, or Coniine (a-propyl piperidine), C 5 H 17 N, an alkaloid occurring, associated with y-coniceine, conhydrine, pseudoconhydrine and methyl conine, in hemlock (Conium maculatum).
Hofmann (Berichte, 1881, 1 4, pp. 494, 6 59) is converted into the hydrocarbon conylene C 8 H 14, a compound that can also be obtained by heating nitrosoconine with phosphoric anhydride to 80-90° C. On heating conine with concentrated hydriodic acid and phosphorus it is decomposed into ammonia and normal octane CsH18.
Canine is a secondary base, forming a nitroso derivative with nitrous acid, a urethane with chlorcarbonic ester and a tertiary base (methyl conine) with methyl iodide; reactions which point to the presence of the = NH group in the molecule.
Hofmann had shown that conine on distillation with zinc dust gave a-propyl pyridine (conyrine).
The a-propyl piperidine so obtained is the inactive (racemic) form of conine, and it can be resolved into the dextroand laevo-varieties by means of dextro-tartaric acid, the d-conine d-tartrate with caustic soda giving d-conine closely resembling the naturally occurring alkaloid.
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 time to 290°-300°, and then distilling.
It may be obtained by brominating conine, and then removing the elements of hydrobromic acid with alkalis.
Methyl conine, C 9 H 19 N or C8H14 N(CH3), is synthesized from conine and an aqueous solution of potassium methyl sulphate at