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

Participants

Reaction Steps

A stirred solution of 5.0 g (30.96 mmol) of nortropinone hydrochloride and 4.6 g (31.89 mmol) of phenylhydrazine hydrochloride in 20 mL of ethanol was heated at reflux for 2.5 hours. After slow dropwise addition of 5 mL of concentrated sulfuric acid, the reaction mixture was stirred and refluxed for an additional 16 hours, and then it was added to a 50 mL of ethanol and sufficient IRA-400 resin was added to bring the mixture to pH 10. Decolorizing carbon (10 g) was added and the mixture was stirred at ambient temperature for 30 minutes. The mixture was filtered through a pad of diatomaceous earth. After the filter cake was washed several times with warm ethanol, the filtrates were combined and concentrated. The residue was chromatographed on silica gel using methylene chloride: methanol: aqueous ammonium hydroxide/91.5: 7.5: 1.0 to afford 3.19 g (52%) of 5,6,7,8,9,10-hexahydro-7,10-iminocyclohept[b]indole identical with that obtained by Method A.

Provenance & Evidence