Cyclohexene → Ethyl 5-amino-1H-indole-2-carboxylate

Participants

Reaction Steps

A mixture of 5-Nitro-1H-indole-2-carboxylic acid ethyl ester 15 (88.7 mg, 0.38 mmol) and cyclohexene (0.1 mL, 0.98 mmol) in THF/MeOH (3/8 mL) in the presence of Pd(OH)2 on activated carbon (Pearlman's catalyst) (2.74 g) was heated to reflux for 5 h. The reaction mixture was cooled to room temperature. The mixture was filtered through a pad of Celite. The Celite and the palladium were washed with EtOAc. The combined solution was concentrated. The residue was purified by flash column chromatography on silica gel, eluting with 5-45% EtOAc/hexane to afford 66.6 mg of ethyl 5-amino-1H-indole 2-carboxylate 20. 1H-NMR (CDCl3): 8.653 (Br, 1H, NH), 7.228 (d, J=8.5-9.0 Hz, 1H, Ar—H), 7.031 (dd, J=1.0 Hz and 2.0 Hz, 1H, Ar—H), 6.932 (d, J=2.5 Hz, 1H, Ar—H), 6.803 (dd, J=2.5 Hz, 1H, Ar—H), 4.379 (q, J=7.0-7.5 Hz, 2H, CH2), 1.396 (t, J=7.0-7.5 Hz, 3H, CH3). LC-MS: 205.2 (MH+).

Provenance & Evidence