L-alanine methyl ester hydrochloride (420 mg) and 7-(5-{3-chloro-4-[(1-methylethyl)oxy]phenyl}-1,2,4-oxadiazol-3-yl)-1H-indole-3-carbaldehyde (D71) (382 mg) was added to a solution of NaOH (120 mg) in methanol (20 mL). After stirring for 0.5 hour, methanol was evaporated off and then after addition of AcOH (0.5 mL) in dichloromethane (40 mL), NaBH(OAc)3 (847 mg) was added. The reaction mixture was stirred at room temperature overnight and quenched by saturated NaHCO3 solution. The organic layer was separated and washed with water and brine. After the solvent was evaporated off the residue was purified by Mass Directed AutoPrep to afford methyl N-{[7-(5-{3-chloro-4-[(1-methylethyl)oxy]phenyl}-1,2,4-oxadiazol-3-yl)-1H-indol-3-yl]methyl}-D-alaninate (D76) (223 mg) as a white solid. MS (ES): C24H25ClN4O4 requires 468; found 491.1 (M+Na+).
