Photolytic syntheses of dl-Laurotetanine, dl-Schefferine & dl-Corytenchine

Abstract

Debenzylation of 1-(5'-benzyloxy-2'-bromo-4'-methoxybenzyl)-6,7-dimethoxy-l,2,3,4-tetra-hydroisoquinoline (V) gave the phenolic tetrahydroisoquinoline (VI) and 12-bromoscheflerine (VII). Photolysis of the hydrochloride of l-(2'-brorno-5'-hydroxy-4'-methoxybenzyl)-6,7-di-methoxy-l,2,3,4-tetrahydroisoquinoline (IV) gave dl-laurotetanine (I), 12-bromoschefferine (VII), dl-schefferine (III), dl-corytenchine (IV) and 1-(3'-hydroxy-4'-methoxy-benzyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (VIII). Compounds III, IV, VII and VIII obtained during photolysis were identical with authentic synthetic samples. Synthetkr dl-schefferine (III) was identical with a natural sample of (-) schefferine.