Cesium carbonate → Ethyl 1-((3,5-dimethylisoxazol-4-yl)methyl)-1H-pyrazole-4-carboxylate

Participants

Reaction Steps

Ethyl 1H-pyrazole-4-carboxylate (4.2 g, 30 mmol), 4-(chloromethyl)-3,5-dimethylisoxazole (5.1 g, 35 mmol), and cesium carbonate (9.8 g, 30 mmol), in DMF (50 mL), were stirred at 80° C. for 12 hours. The reaction was cooled to ambient temperature, diluted with 0.1 N HCl (150 mL) and extracted with ethyl acetate (3×, 75 mL). The combined organic extracts were dried over sodium sulfate and concentrated on the rotovap. The solid product was triturated with ethyl acetate/hexanes(1/9) and collected by filtration to afford ethyl 1-((3,5-dimethylisoxazol-4-yl)methyl)-1H-pyrazole-4-carboxylate (6 g, 80%) as a white solid. 1H NMR (CDCl3, 400 MHz): δ1.34 (t, J=7.2 Hz, 3H), 2.19 (s, 3H), 2.43 (s, 3H), 4.29 (q, J=7.2 Hz, 2H), 5.06 (s, 2H), 7.77 (s, 1H), 7.91 (s, 1H).

Provenance & Evidence