4-Aminobenzoic Acid → Benzoic Acid

To a stirred mixture of 2-chloro-4-phenyl-6,7-dihydro-5H-cyclopenta[d]pyrimidine (1.3 g, 5.4 mmol) in 2-propanol (30 mL) was added 4-aminobenzoic acid (0.82 g, 6.0 mmol) and the mixture was heated to reflux for 4 h. The mixture was cooled to rt and the precipitate was collected by filtration, washed with 2-propanol and dried to give the intermediate benzoic acid as a yellow solid (1.5 g, 84%). A portion of this intermediate (1.3 g, 3.9 mmol) was treated with 2,6-dimethylaniline (498 mg, 4.12 mmol), triethylamine (2.1 mL, 15 mmol) and HATU (1.91 g, 5.00 mmol) in dimethylformamide (10 mL). The stirred mixture was heated to 80° C. overnight, then cooled to rt. The reaction was diluted with ethyl acetate and extracted with water. The organic layer was washed with saturated sodium bicarbonate and concentrated on a rotary evaporator. The resulting residue was purified by preparative reverse phase HPLC to give N-(2,6-dimethylphenyl)-4-[(4-phenyl-6,7-dihydro-5H-cyclopenta[d]pyrimidin-2-yl)amino]benzamide (1.18 g, 69%) as a light yellow solid. 1H NMR (400 MHz, CD3OD): δ 7.98 (m, 6H), 7.56 (m, 3H), 7.17 (m, 3H), 3.18 (m, 2H), 2.98 (m, 2H), 2.25 (s, 6H), 2.17 (m, 2H). MS (EI) for C28H26N4O: 435.2 (MH+).