23.2 g (74.28 mmol) of ethyl 5-amino-1-(2-fluorobenzyl)-1H-indole-2-carboxylate from Example XXXVI and 15.03 g (20.71 ml, 148.56 mmol) of triethylamine are added to 300 ml of dichloromethane. The mixture is cooled to 0° C., and a solution of 11 g (11.35 ml, 81.71 mmol) of 3,3-dimethylbutyryl chloride in 300 ml of dichloromethane is added. The mixture is stirred at RT overnight and, for work-up, poured into water. The pH is adjusted to 7 and the mixture is extracted 3 times with ethyl acetate. The combined organic phases are dried over sodium sulphate, filtered and concentrated under reduced pressure.
