Cyclopropylamine → 7-Hydroxyindole

Participants

Reaction Conditions

Reaction Steps

7-Chloroacetyloxy-1,4-dihydro-4-methylcyclopent b!indol-3(2H)-one (15.0 g) and cyclopropylamine (9.6 g) were dissolved in 300 ml toluene and cooled to -10° C. Titanium tetrachloride (6.3 g) dissolved in 50 ml toluene was added slowly to the first solution. The reaction mixture was allowed to come up to room temperature and stirred overnight. The next day another 1.5 equivalents of the amine (4.6 g) was added to the reaction mixture and the mixture was stirred for one hour. The reaction mixture was filtered through a pad of silica gel, eluting with 3:1 hexane/ethyl acetate, giving a yellow oil after removal of solvents. 3-Cyclopropylamino-4-methyl-1,2,3,4-tetrahydrocyclopent b!-indol-7-ol was isolated as a light yellow solid (3.3 g) after flash chromatography and recrystallization from ethyl acetate.

Provenance & Evidence