CRYPTOPLEURINE, A SYNTHESIS BASED ON BIOGENETIC CONSIDERATION

A ten-stage synthesis of (±)-cryptopleurine is described. In line with biogenetic postulates it involves oxidativa coupling of 2-(3,4-dihydroxyphenyl)-cis-3-(4-hydroxyphenyl)quinolizidin-4-one (VII; R 1 = H, R2 = O), itself obtained in six steps from 2-methylpyridine, methyl 3.4-dimethoxybenzoate, and 4-methoxyphenylacetyl chloride. The resulting dienone was found to have undergone dehydrogenation and, after rearrangement with acid, methylation, and reduction, afforded the alkaloid (I; R1 = R2 = R3 = H ; n = 2).