Diethyl acetylenedicarboxylate → 2-[2-Chloro-5-(methoxycarbonyl)phenylamino]-2-butenedioic acid diethyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 22 (5.00 g, 26.9 mmol) in ethanol (50 mL) was added but-2-ynedioic acid diethyl ester (5.02 g, 29.5 mmol) at room temperature. The reaction mixture was heated at 90° C. for 18 h and then cooled to room temperature. The solvent was removed under reduced pressure. The crude residue was washed with a solution of 1:1 Hexanes/diethyl ether (100 mL) to afford a white solid (23, 9.08 g, 95.1%). 1H NMR (DMSO-d6, 300 MHz) δ ?9.80 (s, 1H), 7.65-7.66 (m, 2H), 7.38 (s, 1H), 5.54 (s, 1H), 4.13-4.22 (m, 4H), 3.83 (s, 3H), 1.22 (t, J=7.1 Hz, 3H), 1.11 (t, J=7.1 Hz, 3H).

Provenance & Evidence