A novel electrochemical method for benzoylation of aminoalcohols with methyl benzoates at room temperature

A novel electrochemical method of benzoylating aminoalcohols 2 by use of methyl benzoates 1 at room temperature was developed. 2-Aminoethanols 2 (n = 0, R 3 = H) and 3-aminopropanols 2 (n = 1, R 3 = H) gave the corresponding benzamides 4 , as a result of electrochemical transesterification followed by O,N-actyl migration. In contrast, o- and m-aminobenzylalcohols ( 7 a and 7 b) and trans-4-(aminomethyl)cyclohexanemethanol ( 8 a) afforded the corresponding benzoic esters, since their acyl migration is hindered. A local anesthetic, procaine, was prepared by using this electrochemical reaction. A mechanism for electrochemical transesterification, which involves a formation of alcoholate anion by a one-electron reduction of alcohol, is presented. Keywords: amides, aminoalcohols, benzoylation, electrochemical, esters.