Convenient and Efficient Synthesis of 1-Oxo-1,2,3,4-tetrahydrocarbazoles via Fischer Indole Synthesis

Abstract

A convenient synthesis of 1-oxo-1,2,3,4-tetra-hydrocarbazoles has been developed by reaction of 2-aminocyclohexanone hydrochlorides with various phenylhydrazine hydrochlorides via Fischer indole synthesis under mild conditions. The method is more satisfactory in terms of the easy availability of starting materials and the simple one-pot operation.

Keywords:

• 2-Aminocyclohexanone
• Fischer indole synthesis
• 1-oxo-1,2,3,4-tetrahydrocarbazole
• phenylhydrazine

Notes

^a The ratio of 2-aminocyclohexanone hydrochloride 1a and phenylhydrazine hydrochloride 2a.

^b Isolated yield.

^c No reaction had occurred.

^a Isolated yield.

^b A 1.3:1 mixture of 3m and 3m′.