In order to derive kainic acid to a more simpler compound and submit it to the Hofmann degradation, the carboxyl was substituted with a methyl group. Dihydrokaininediol was led through N, O, O-tritosyldihydrokaininediol (XVI), m.p. 120°, C31H39O8NS3, to N-tosyldihydrokainine diiodide (XVII), m.p. 97°, C17H25O2NSI2. Dimethyl N-benzoyldihydrokainate (XVIII), m.p. 94°, C19H25O5N, was prepared from dimethyl dihydrokainate hydrochloride, reduced to N-benzyldihydrokaininediol (XIX), b.p2 188°, C17H27O2N, and chlorinated to N-benzyldihydrokainine dichloride hydrochloride (XX), m.p. 186°, C17H26NCl3. Dehalogenation was attempted by several methods on (XVII) and (XX) but the attempt failed. N-Methyldihydrokaininediol (X) was chlorinated to N-methyldihydrokainine dichloride hydrochloride (XXI) which was treated with alkali after zinc powder reduction, in acid medium, and the oil (XXII) of b.p16 86° thereby obtained was catalytically reduced to form the objective N-methylmethylethylisopropylpyrrolidine (XXIII-i), b.p16 91°, [α]D18: +40°, C11H23N; picrate, m.p. 94°; methiodide (XXIV-i), m.p. 197°. From the results of ozonization, catalytic reduction, and infrared absorption spectrum, (XXII) was assumed to be N-methylmethylvinylisopropylpyrrolidine. High temperature-high pressure reduction of dihydrokaininediol in ethanolic solution, with copper-chromium catalyst, afforded two substances, (a) b.p22 75-80° and (b) b.p27 140-145°. (a) is N-ethylmethylethylisopropylpyrrolidine formed by N-ethylation with ethanol while (b) is a compound in which one of the -CH2OH group had been left intact in this reaction. Based on these findings, N-methyldihydrokaininediol was similarly treated in methanol solution and afforded (XXIII-ii), b.p21 90-95°, which formed a picrate of m.p. 124-125° and a methiodide (XXIV-ii) of m.p. 187°, [α]D17: +5°. It was assumed that (XXIII-ii) was racemized during the high temperature-high pressure reduction.
