Dichloromethane → 1-(3-Thienyl)-1H-indole-2,3-dione

Participants

Reaction Steps

Copper(II) acetate monohydrate (4.25 g, 23.4 mmol) was heated at reflux in acetic anhydride (30 mL) for 2 h. The mixture was filtered and washed with anhydrous ether (500 mL). The solid was dried in vacuo at 55° C. for 16 h. Dichloromethane (1 mL) was added to a mixture of copper(III) acetate (62 mg, 0.34 mmol), isatin (50 mg, 0.34 mmol), and thiophene-3-boronic acid (87 mg, 0.68 mmol), followed by triethylamine (0.10 mL, 0.68 mmol) under argon. The resulting solution was stirred for 16 h at room temperature. The reaction mixture was then recharged with 0.10 mmol copper(II) acetate, 0.10 mmol of 3-thiophene boronic acid, and 1 drop of triethylamine, and the mixture was heated at 50° C. for 6 h. The crude material was purified by preparative TLC using 3:97 methanol in chloroform as the eluent, giving the desired product as a yellow solid (25 mg, 0.11 mmol, 33%). 1H NMR (400 MHz): δ 7.70 (d, J=7.5, 1H), 7.58 (t, J=7.8, 1H), 7.50 (d, J=5.1, 1H), 7.48 (s, 1H), 7.24 (d, J=5.1, 1H), 7.18 (t, J=7.51, 1H), 7.05 (d, J=8.0, 1H).

Provenance & Evidence