389 mg (1.17 mmol) of 1-(2,4-difluorobenzyl)-5-nitro-1H-indole-2-carboxylic acid from Example XXII, 336 mg (1.76 mmol) of N′-(3-dimethylaminopropyl)-N-ethyl-carbodiimide×HCl and 71.5 mg (0.59 mmol) of 4-dimethylaminopyridine are initially charged in 30 ml of a 10:1 dichloromethane:DMF mixture. 156 mg (0.13 ml, 1.40 mmol) of 4-fluoroaniline are added, and the mixture is stirred at RT for 4 hours. For work-up the mixture is diluted and extracted with aqueous hydrochloric acid and ethyl acetate. The organic phase is washed with sat. sodium chloride solution, dried with sodium sulphate, filtered and dried under reduced pressure.
