New carbamate analogs of (-)-physostigmine were prepared from (-)-eseroline and various isocyanates, including optically active 1- phenylethyl isocyanates. N-Benzylation of (-)-N1-noreseroline O- methylether prepared by total synthesis afforded N1- benzylnorphysostigmine, after O-demethylation and reaction with N-methylisocyanate, and N1-norphysostigmine after catalytic debenzylation over Pd-catalyst in methanol. A larger quantity of (+)-physostigmine was prepared by total synthesis, using for purification of intermediates and end product fumarate and salicylate salts and avoiding column chromatography.
