For the studies on modification of mesembrine (II), N-methyl-2-[8-(3, 4-dimethoxyphenyl)-1, 4-dioxaspiro [4, 5] decan-8-yl] ethylamine (I) was synthesized from 1, 4-dioxaspiro [4, 5] decan-8-one (III) : the Cope reaction of III with ethyl cyanoacetate gave 1, 4-dioxaspiro [4, 5] decan-8-ylidene cyanoacetate (IV), whose Grignard reaction with 4-halogeno-1, 2-dimethoxybenzene afforded ethyl 8-(3, 4-dimethoxyphenyl)-1, 4-dioxaspiro-[4, 5] decane-8-cyanoacetate (V). Hydrolysis of V followed by decarboxylation gave 8-(3, 4-dimethoxyphenyl)-1, 4-dioxaspiro [4, 5] decane-8-acetonitrile (VIII), which was reduced with LiAlH4 to obtain 2-[8-(3, 4-dimethoxyphenyl)-1, 4-dioxaspiro [4, 5] decan-8-yl]-ethylamine (IX). Treatment of IX with ethyl chloroformate followed by reduction with LiAlH4 furnished I.
