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

Participants

Reaction Conditions

Reaction Steps

NBS (2.03 g, 11.41 mmol) was added in portions to a 75 mL sealed tube reactor containing methyl 5-methyl-4-(1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate (2.1 g, 8.89 mmol) [prepared according to the procedure of Preparation 10] in Tetrahydrofuran (THF) (40 ml) at room temperature. The mixture was heated to 70° C. for 1 hour. The reaction mixture was partitioned between CHCl3 and H2O, the organic layer dried with Na2SO4, the reaction mixture adsorbed onto silica and purified via column chromatography (15-40% EtOAc/Hex) affording the title compound (2.57 g, 8.15 mmol, 92%): LC-MS (ES) m/z=316 (M+H)+.

Provenance & Evidence