Water → Ethyl 4-bromothiophene-3-carboxylate

Participants

Reaction Conditions

Reaction Steps

Isopropylmagnesium chloride (263 mL of a 2.0 M solution in tetrahydrofuran, 0.527 mol) was added via cannula over 35 min to a solution of 3,4-dibromo-thiophene (102 g, 0.421 mol) in tetrahydrofuran (600 mL) at 0° C. The mixture was allowed to warm to 25° C. and was stirred at that temperature for 18 h. Water (25 mL) was added, and the mixture was stirred at 25° C. for 15 min, and then was concentrated in vacuo to ˜200 mL volume. The concentrate was partitioned between 1.0 M aqueous hydrochloric acid solution (400 mL) and ethyl acetate (2×350 mL). The combined organic layers were dried over sodium sulfate, filtered and were concentrated in vacuo to afford the crude product, 4-bromo-thiophene-3-carboxylic acid ethyl ester (91.9 g, 0.391 mol, 93%), as a yellow/brown oil. 1H NMR (400 MHz, CDCl3) δ: 1.40 (3H, t, J=7.5 Hz), 4.36 (2H, q, J=7.3 Hz), 7.31 (1H, d, J=3.9 Hz), 8.10 (1H, d, J=3.0 Hz).

Provenance & Evidence