Studies on the syntheses of heterocyclic compounds. Part 777. A synthetic approach to seco-mitosane type of compound related to mitomycins

Abstract

1,2,3,4,5 6-Hexahydro-5,5,8-trimethoxy-9-methyl-1-benzazocine-7,10-dione (1b) has been synthesised from 2,3-dihydro-7-methoxy-6-methyl-1H-pyrrolo[1,2-a]indole-5.8-dione (10c). The key intermediate, 7,10-diacetoxy-5-trifluoroacetoxy-1-trifluoroacetyl-1,2,3,4,5,6-hexahydro-8-methoxy-9-methyl-1-benzazocine (13b), was prepared by a ring-opening reaction of 5,8-diacetoxy-1,2,9,9a-tetrahydro-7-methoxy-6-methyl-1H-pyrrolo-[1,2-a]indole (12) with trifluoroacetic anhydride. An alternative route to 1,2,3,4,5,6-hexahydro-1-benzazocine (7d) from 2,3,9,9a-hexahydro-7-methoxy-6-methyl-1H-pyrrolo[1,2-a]indole (6) has also been devised.