Method of preparation of physostigmine carbamate derivatives from eseretholes

摘要

This invention relates to a process for the preparation of a product of the formula <IMAGE> (I) wherein R, R1, R2, X and m are defined within which process comprises (a) contacting a compound of Formula II <IMAGE> (II) wherein R3 is loweralkyl, with a reagent selective from the group consisting of aluminum chloride, hydrobromic acid and boron tribromide followed by tartaric acid to afford a compound of Formula III <IMAGE> (III) wherein R, X and m are as defined above; (b) contacting the reaction mixture containing compound of Formula IV <IMAGE> (IV) wherein R4 is hydrogen or loweralkyl in the presence of a carboxylic acid of the formula R5COOH wherein R5 is loweralkyl to afford a compound of formula V <IMAGE> (V) wherein R, R4, X and m are as above; contacting the reaction mixture containing the compound of Formula V obtained in step (b) with a compound of the formula R1R2NH wherein R1 and R2 are as above; and isolating the product of Formula I.