N-bromobutanimide → methyl 4-(4-bromo-1-ethyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate

Participants

Reaction Conditions

Reaction Steps

To a solution of methyl 4-(1-ethyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate (0.45 g, 1.9 mmol) [see example 92(a)] in THF (5 mL) was added NBS (0.33 g, 2.5 mmol). The reaction mixture was heated to 70° C. under nitrogen. After 2 h, the reaction mixture was concentrated under vacuum and purified on silica (EtOAc/hexanes, 10-30%) to afford the title compound (0.47 g, 78%). LC-MS (ES) m/z=316 (M+H)+.

Provenance & Evidence