EFFICIENT SYNTHESES OF THE MARINE ALKALOIDS MAKALUVAMINE D AND DISCORHABDIN C - THE 4,6,7-TRIMETHOXYINDOLE APPROACH

摘要

A new and efficient synthesis of the tricyclic quinonimine 20 as its trifluoroacetate 23 has been developed starting from the commercially available 2,4,5-trimethoxybenzaldehyde and proceeding via the hitherto unknown 4,6,7-trimethoxyindole (7). Quinonimine 23 is the late stage key intermediate in several previously reported syntheses of the biologically active pyrrolo[4,3,2-de]-quinoline marine alkaloids discorhabdin C (1) and makaluvamine D (3). [References: 21]