To a solution of oxalyl chloride (2.1 mL) in dichloromethane (125 mL) at 0° C. was added a solution of N,N-dimethylformamide (2.32 mL) in Dichloromethane (DCM) (75 mL) dropwise during 30 mins. The reaction mixture was stirred at 0° C. for another 15 minutes. A solution of 7-(5-{3-chloro-4-[(1-methylethyl)oxy]phenyl}-1,2,4-oxadiazol-3-yl)-1-methyl-1H-indole (D58) (7.4 g) in Dichloromethane (100 mL) was added in one portion. the mixture was stirred and warmed to room temperature slowly. After stirred at room temperature for 5 hours, dichloromethane was evaporated off. Ethyl acetate (300 mL), water (100 mL) and concentrated HCl solution (5 mL) was added to the residue. The mixture was stirred for 30 minutes and KOH was added to adjust pH value to about 8. The organic layer was separated, washed with water and brine, then dried over MgSO4. Filtration and evaporation afforded the product 7-(5-{3-chloro-4-[(1-methylethyl)oxy]phenyl}-1,2,4-oxadiazol-3-yl)-1-methyl-1H-indole-3-carbaldehyde (D61) (5.2 g). δH (CDCl3, 400 MHz): 1.47 (6H, d), 3.87 (3H, s), 4.71-4.77 (1H, m), 7.09 (1H, d), 7.44 (1H, t), 7.68 (1H, dd), 7.72 (1H, s), 7.89 (1H, dd), 8.26 (1H, d), 8.56 (1H, dd), 10.06 (1H, s). MS (ES): C21H18ClN3O3 requires 395. found 396.1 (M+H+).
