Indole → 1,2,3,4-Tetrahydrocarbazole

Participants

Reaction Steps

In Scheme XVII, Step A, a phenylhydrazine salt (for example the hydrochloride salt) of formula (4), is reacted with a cyclic ketone of formula (3), wherein Z=OBn, in a Fischer indole reaction to provide a tetrahydrocarbazole of formula (5). The hydrazine and ketone are reacted in acetic acid and heated at about 60 to 110° C., for about 4 to 48 hours. The product is isolated by removal of the acetic acid under reduced pressure and trituration of the material in an inert solvent, preferably dichloromethane. After filtration, the filtrate is concentrated and the resulting material purified using standard techniques such as recrystillization or silica gel chromatography.

Provenance & Evidence