Vomicine methiodide

Vomicine methiodide is likewise hydrolyzed by warm alkali to the betaine CCXLI (195). 

Vomicine methiodide is very similar to strychnine methiodide, with warm alkali converting the intermediate methohydroxide to the betaine, methylvomicine. The metho salts of vomicine are regenerated by mineral... 

Vomicine (C22H24O4N2) (8), like strychnine, is a weak base (it will not form a methiodide directly (25, 29) as will dihydrovomicine (29)) but shows greater solubility in most solvents (especially acetone (8)) and hence is found in the mother liquors from the purification of strychnine. The common origin of these two alkaloids, as well as their similar properties and analogous reactions, makes it highly probable that vomicine has the strychnine nucleus and many of the characteristic groupings of the latter... 

The weak basicity of vomicine has been ascribed to the grouping -0-CH2-Nb. In the event of such a grouping in vomicine, the strychnine ethanamine chain must be replaced by an ethyl side chain which at various times has been located at C3 and C4 (CXII) to conform with the strychnine formula. In agreement with this formula vomicine is a tertiary amine (with no N-CH3 grouping (Herzig Meyer) (8) ) for, although the methiodide is not formed from the direct combination of the two reactants, it has been obtained by the action of sodium iodide upon an aqueous solution of vomi-... 

The above structure for the colorless desoxyvomicine fails to offer a satisfactory explanation for the formation of a methiodide by this base, while vomicine fails to react with methyl iodide under similar conditions. Reduction of an acetic acid solution of desoxyvomicine methiodide by sodium amalgam yields the base C23H30O3N2 with two imino-methyl groups (29) (desoxydihydrovomicine and methane result from a similar reduction of desoxydihydrovomicine methiodide (32)). Base C2JH30O3N2 reacts smoothly with methyl iodide, while thermolysis of the derived metho-hydroxide yields trimethylamine. It would seem difficult to find an adequate explanation for the formation of trimethylamine on the present formula for desoxyvomicine. 

Dimethylvomicine-I methiodide with potash in methyl alcohol at 110-120° yields some trimethylamine, but is chiefly converted into an isomeride, C25H85O4NJI, m.p. 278° dec.). The lactam ring remains intact in both the methyl- and dimethyl-vomicines. Three of these products have been reduced electrolytically giving metbylvomicidine-I, m.p. 280° dec.) dimethylvomicidine-I, Cj4H340jN2, m.p. 286° (dec.) and dimethylvomicidine-II, m.p. 236° dec.). 

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