Yield:603309-90-6 68%

Reaction Conditions:

with manganese(IV) oxide in dichloromethane; for 2 h;Heating / reflux;

Steps:

172

Oxidation; Add manganese (IV) oxide (3.0 grams) to a solution of 2, 3-dihydro-6-fluoroindole- 7-carboxaldehyde (350 mg, 2.11 mmol) in dichloromethane and reflux for 2 hours. Cool to room temperature and filter through celite. Concentrate the filtrate under reduced pressure to provide the title compound as an off-white solid (240 mg, 68 %). 1H-NMR (400 MHz, DMSO-d6) : 89. 7 (s, 1H), 7.1 (dd, 1H), 6.55 (d, 1H), 6.15 (m, 1H), 5.75 (s, 1H).

References:

WO2003/76442,2003,A1 Location in patent:Page/Page column 80