Studies on the syntheses of heterocyclic compounds. Part DCXX. Total synthesis of (±)-orientalidine and a positional isomer

Abstract

The total synthesis of (±)-orientalidine (2) was accomplished by treatment of (±)-demethylmecambridine (3) with methylene chloride and sodium hydride in dimethylformamide. 11-Hydroxy-12-hydroxymethyl-3,10-dimethoxy-1,2-methylenedioxyberbine (16) was synthesised from 1-(3-benzyloxy-4-methoxybenzyl)-1,2,3,4-tetrahydro-6-methoxy-7,8-methylenedioxyisoquinoline (11) by way of 11-benzyloxy-3,10-dimethoxy-1,2-methylenedioxyberberine (12) and the corresponding phenolic base (15). Treatment of the hydroxymethylated berbines (5) and (16) under the same conditions as for the synthesis of orientalidine gave the corresponding berbines (6) and (18) containing a fused m-dioxin system.