EDCI (151 mg) and HOBT (121 mg) were added to a solution of 3-cyano-4-[(1-methylethyl)oxy]benzoic acid (can be prepared as described in WO2005/58848, 135 mg) in DMF (5 mL) at RT. The resulting solution was stirred for 45 min. 1,1-dimethylethyl 3-{6-[(hydroxyamino)(imino)methyl]-1H-indol-3-yl}propanoate (D16) (199 mg) was added and the reaction mixture was stirred at RT for 3 hours. The reaction mixture was heated to 80° C. and stirred at that temperature for 5 hours. DMF was evaporated. EtOAc (100 mL) was added and the organic solution was washed with saturated aqueous sodium bicarbonate solution (75 mL) and water (75 mL). The organic fraction was dried over anhydrous magnesium sulfate. The dried solution was concentrated. The residue was purified by Biotage (25→33% EtOAc in hexane) to afford 1,1-dimethylethyl 3-[6-(5-{3-cyano-4-[(1-methylethyl)oxy]phenyl}-1,2,4-oxadiazol-3-yl)-1H-indol-3-yl]propanoate (D19) (105 mg) as a white solid. δH (DMSO-d6, 400 MHz): 1.38 (9H, s), 1.39 (6H, d), 2.60 (2H, t), 2.96 (2H, t), 4.98 (1H, m), 7.35 (1H, d), 7.55 (1H, d), 7.72 (2H, m), 8.12 (1H, d), 8.42 (1H, dd), 8.51 (1H, d), 11.21 (1H, s). MS (ES): C27H28N4O4 requires 472; found 473.0 (M+H+).
