To a mixture of 2-(2,6-dichlorophenyl)-1,3-dioxo-2,3-dihydro-1H-isoindole-5-carboxylic acid (403 mg), EDCI (121 mg) and HOBt (135 mg) in DMF (8 mL) was added 3,4-dimethylaniline (53 mg) and the mixture was stirred at room temperature for 24 h. The mixture was poured into water and was extracted with EtOAc. The organic phase was washed with water (3×) and dried over sodium sulfate. The solvent was removed under reduced pressure and the residue crystallized from EtOAc to give 2-(2,6-dichlorophenyl)-1,3-dioxo-2,3-dihydro-1H-isoindole-5-carboxylic acid (3,4-dimethylphenyl)-amide as a pale-yellow solid, mp=238-240° C.; MS (m/z) 439 (M−1); 1H NMR DMSO-d6, 400 MHz) δ 10.49 (s, 1H), 8.62 (s, 1H), 8.50 (d, J=7.83 Hz, 1H), 8.24 (d, J=7.58 Hz, 1H), 7.80 (s, 1H), 7.78 (s, 1H), 7.67 (t, 1H), 7.59 (s, 1H), 7.53 (d, J=8.08 Hz, 1H), 2.24 (s, 3H), 2.21 (s, 3H).
