Indole → 5,6,7,8,9,10-Hexahydro-7,10-iminocyclohept[b]indole

Participants

Reaction Steps

Accordingly, phenylhydrazine or 4-fluorophenylhydrazine is condensed with nortropinone or pseudo-pelletierine (9-azabicyclo-[3.2.1]nonan-3-one) under conditions of the Fischer indole synthesis to afford 5,6,7,8,9,10-hexahydro-7,10-iminocyclohept[b]indole or 6,7,8,9,10,11-hexahydro-7,11-imino-5H-cyclooct[b]indole or the corresponding-2-fluoro derivatives. Alkylation of the basic nitrogen in these compounds with the appropriately substituted alkyl halide or tosylate in dimethylformamide affords the compounds of Formula I wherein R1 is hydrogen. Alternatively, compounds of Formula I may be obtained by acylation of the hexahydro-7,10-iminocyclohept[b]indole or hexahydro-7,11-imino-5H-cyclooct[b]indole followed by reduction of the resulting amide with, for example, lithium aluminum hydride. Compounds of Formula I in which R1 is other than hydrogen or phenyl are prepared by abstraction of the a proton from the indole nitrogen, for example with sodium hydride in dimethylformamide, followed by reaction of the resulting anion with the required alkyl or aralkyl halide. Compounds of Formula I in which R1 is phenyl are prepared by alkylation or acylation/reduction of 5-phenyl-5,6,7,8,9,10-hexahydro-7,10-iminocyclohept-[b]indole (J. G. Berger and P. Tahbaz, U.S. Pat. No. 4,360,673, Nov. 23, 1982) or 5-phenyl-6,7,8,9,10,11-hexahydro-7,11-imino-5H-cyclooct[b]indole as outlined above.

Provenance & Evidence