Sodium Carbonate → Ethyl 3-bromo-1-(4-methoxybenzyl)-1H-thieno[2,3-c]pyrazole-5-carboxylate

Participants

Reaction Conditions

Reaction Steps

3,5-Dibromo-1-(4-methoxybenzyl)-1H-pyrazole-4-carbaldehyde (1.3301 g, 3.56 mmol), ethyl thioglycolate (0.419 ml, 3.73 mmol), and sodium carbonate (0.761 g, 7.18 mmol) were dissolved in ethanol (35 ml) at 25° C. under Ar in a sealed heavy-walled reaction vessel. The reaction mixture was warmed to 80° C. and allowed to stir for 4 h. The reaction was stopped, cooled to room temperature, quenched by addition of saturated aqueous ammonium chloride (40 mL), and the mixture extracted with ethyl acetate (3×30 mL). The combined organic phases were washed with saturated aqueous sodium chloride (1×20 mL), dried (sodium sulfate), filtered, and the solvent evaporated under reduced pressure. The crude product was purified by flash chromatography (RediSep SiO2, 120 g column) on a CombiFlash Rf purification system eluting with ethyl acetate-hexanes (0-25%). The title compound (1.2063 g, 3.05 mmol, 86% yield) was recovered as a white solid. LC-MS [M+1]=395.2.

Provenance & Evidence