1,1'-Carbonyldiimidazole → (RS)-N-(4-cyano-benzyl)-2-ethoxy-2-(3-phenyl-[1,2,4]oxadiazol-5-yl)-acetamide

Participants

Reaction Conditions

Reaction Steps

To a solution under N2 of 1,1′-carbonyldiimidazole (272 mg) in THF (10 ml) was added a solution of (RS)-N-(4-cyano-benzyl)-2-ethoxy-malonamic acid (400 mg) in THF (10 ml). The mixture was stirred for 30 min before addition of a solution of benzamidoxime (228 mg) in THF (20 ml). After stirring 18 h the solvent was evaporated. The crude product was dissolved in EtOAc and extracted with HCl 0.1 N, NaHCO3 and brine. After drying (MgSO4) the solvent was evaporated. The resulting white powder was redissolved in DMF (15 ml) and this solution was heated 5 min in a sealed tube at 140° C. using microwave radiation. DMF was removed, the residue was diluted with EtOAc and washed twice with water. The aqueous phases were extracted with more EtOAc. The combined organic phases were dried over MgSO4 and the solvent was evaporated. Flash chromatography (MeCl2/Et2O, from 100:0 to 95:5) yielded (RS)-N-(4-cyano-benzyl)-2-ethoxy-2-(3-phenyl-[1,2,4]oxadiazol-5-yl)-acetamide, 305 mg (55%); lightly yellow oil. MS 363.1 (100, [M+H]+), 380 (53, [M+NH4]+).

Provenance & Evidence