EDCI (187 mg) and HOBT (149 mg) were added to a solution of 3-cyano-4-[(1-methylethyl)oxy]benzoic acid (100 mg) in THF (5 mL). The mixture was stirred at room temperature for 1 hour followed by addition of ethyl 3-{5-[(Z)-(hydroxyamino)(imino)methyl]-1H-indol-2-yl}propanoate (D31) (201 mg). The resulting mixture was stirred at room temperature for 2 hrs followed by addition of TBAF (510 mg). The reaction vessel was sealed and heated in Biotage Initiator to 120° C. for 2 hrs. After cooling the reaction, THF was removed. The residue was dissolved in EtOAc. The organic solution was washed with saturated aqueous sodium bicarbonate solution. The organic solution was dried over anhydrous sodium sulfate. The dried solution was concentrated. The residue was purified by column chromatography to afford ethyl 3-[5-(5-{3-cyano-4-[(1-methylethyl)oxy]phenyl}-1,2,4-oxadiazol-3-yl)-1H-indol-2-yl]propanoate (D114) (68 mg). The product was directly used in the next step without identification.
