Tropane Alkaloid Synthesis Routes To Improve Its Asymmetric Synthesis

A valuable intermediate in the syntheses of a great part of tropane alkaloids is trop-△~6-3α-ol, a suggested common intermediate for the biogenesis of many tropane alkaloids. Several routes for synthesizing this conpound were studied.The routes starting from cycloheptanone, cyclohexene, cyclo-hexanone were attemped by various methods without success. The route starting fron pyrrol has been achieved, by which trop-△~6-3α-ol was synthesized with overall yield 47%.2α,4α-dimethyl-△~6-trop-3α-ol also has been synthesized from pyrrol with overall yield 57%.An asymmetric synthesis of anisodine has been studied. ( + ) or (- ) anisodine were obtained respectively with e · e 52% 75%, starting from trop-△~6-3α-ol. which was converted into 3α-atropoyltropene-6, and then epoxidation, asymmetric dihydroxylation.A stereospecific synthesis of scopolamine has been achieved through resolution of tropic acid.The routes for synthesizing anisodine and scopolamine shortened 6 steps by the improved method.An innovation in synthesis of the analogue Ⅱ , a cholinergic trapane alkaloid, was reported. The results of preliminary pharmacological tests showed that the isomer of analogue Ⅱ , Ⅱ A, Ⅱ B, which have been obtained for the first time, exhibited very strong cholinergic activity.