Acetonitrile → ethyl 4-bromo-3,5-dimethyl-1H-pyrrole-2-carboxylate

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Reaction Conditions

Reaction Steps

3,5-Dimethyl-1H-pyrrole-2-carboxylic acid ethyl ester (204 g), 177 g of potassium carbonate and 1428 mL of acetonitrile were stirred and cooled to 4° C. in an ice bath. N-Bromosuccinimide (228 g) was added in portions with vigorous stirring keeping the temperature under 17° C. The mixture was warmed to 20° C. and 2856 mL of water was slowly added. The precipitate was collected by vacuum filtration and washed three times with 400 mL of ethanol:water 1:2 each time. The solids were dried under vacuum at 60° C. to give 228 g (76% yield) of 4-bromo-3,5-dimethyl-1H-pyrrole-2-carboxylic acid ethyl ester as an off-white solid. 1H-NMR (dimethylsulfoxide-d6) δ 1.26 (t, 3H, CH3), 2.14, 2.17 (2×s, 2×3H, 2×CH3), 4.20 (d, 2H, CH2O), 11.75 (br s, 1H, NH). MS m/z 246, 248 [M+1].

Provenance & Evidence