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

Participants

Reaction Conditions

Reaction Steps

NBS (747 mg, 4.20 mmol) was added in portions to a 50 mL sealed tube reactor containing methyl 4-(1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate (860 mg, 3.48 mmol) [prepared according to the procedure of Example 37] in Tetrahydrofuran (THF) (17 mL) at room temperature. The mixture was heated to 70° C. for 1.5 hours, cooled to room temperature and partitioned between CHCl3 and H2O. The organic layer was dried with Na2SO4, adsorbed onto silica and purified via column chromatography (20-40% EtOAc/hexanes) affording the title compound (867 mg, 83%): LC-MS (ES) m/z=303 (M+H)+.

Provenance & Evidence