Ammonia → 1,2,3,3a,4,8b-Hexahydrocyclopenta[b]indole

Participants

Reaction Conditions

Reaction Steps

1.9 g of sodium cyanoborohydride are added in portions to a solution of 1.5 g of 1,2,3,4-tetrahydrocyclopenta[b]indole in 40 ml of acetic acid cooled to 15° C. The reaction medium is stirred for 20 hours while allowing it to rise to ambient temperature and then the pH is brought to neutrality with a 28% aqueous ammonia solution. The reaction mixture is diluted with water and then extracted with dichloromethane, and the organic phase is washed with a saturated sodium chloride solution, dried over magnesium sulfate, filtered, and concentrated under reduced pressure. The residue is purified by silica column chromatography, elution being carried out with a mixture of heptane and ethyl acetate (95/05), so as to give 1.3 g of 1,2,3,3a,4,8b-hexahydrocyclopenta[b]indole in the form of a colorless oil.

Provenance & Evidence