3-Oxocyclohexanecarboxylic acid (27.2 mg, 0.19 mmol) was added to a stirred solution of 4-chloro-N-(4-methoxyphenyl)benzohydrazide hydrochloride (50 mg, 0.16 mmol) in acetic acid (0.5 mL), the mixture was heated at 80° C. under nitrogen for 3 h, then it was allowed to cool to ambient temperature and stirred overnight. Ice-water (2 mL) was poured into the cold reaction mixture and the formed precipitate was collected by filtration, carefully washed with water and dried in vacuo to yield the title compound (50 mg, 82%) as an off-white solid. C21H18ClNO4, Mr=383.82; 1H NMR (400 MHz, DMSO-d6) d: 1.79-1.87 (m, 1H), 2.11-2.14 (m, 1H), 2.57-2.75 (m, 5H), 6.73 (dd, J=2.8/9.0 Hz, 1H), 6.97 (d, J=2.8 Hz, 1H), 7.06 (d, J=9.2 Hz, 1H), 7.62-7.69 (m, 4H); LCMS (ESI) tR: 2.82 min (>99%, ELSD), m/z: 384.0 [M+1]+.
