1,1'-Carbonyldiimidazole → 3-(4-amino-1,2,5-oxadiazol-3-yl)-4-(3-bromo-4-fluorophenyl)-1,2,4-oxadiazol-5(4H)-one

Participants

Reaction Conditions

Reaction Steps

A mixture of 4-amino-N-(3-bromo-4-fluorophenyl)-N′-hydroxy-1,2,5-oxadiazole-3-carboximidamide (65.7 g, 208 mmol), N,N-carbonyldiimidazole (Sigma-Aldrich) (50.6 g, 312 mmol, 1.5 equiv.), and ethyl acetate (750 mL) was heated to 60° C. and stirred for 20 min. LCMS indicated reaction completed. The reaction was cooled to room temperature, washed with 1 N hydrochloric acid (2×750 mL), dried over sodium sulfate, and concentrated. The crude product was triturated with a mixture of dichloromethane, ethyl acetate, and diethyl ether to give the desired product (60.2 g, 85%) as an off-white solid. 1H NMR (300 MHz, DMSO-d6) δ 8.05 (m, 1H), 7.69 (m, 1H), 7.57 (t, 1H, J=8.7 Hz), 6.58 (s, 2H); C10H5BrFN5O3 (MW 342.08), LCMS (EI) m/e 342/344 (M++H).

Provenance & Evidence