Microbial transformations of natural antitumor agents. IV. Formation of N-(2)-nor-d-tetrandrine by Cunninghamella blakesleeana (ATCC 8688a).

Microbial transformation experiments have been conducted with the antitumor alkaloid, d-tetrandrine. The alkaloid is selectively demethylated at the N-(2)-position by Cunninghamella blakesleeana ATCC 8688a. The biotransformation reaction is highly selective and uncomplicated by side-product formation. N-demethylation of the alkaloid using methylchloroformate is not regio-specific. Procedures used in screening microorganisms for their abilities to yield metabolites of d-tetrandrine are evaluated.