To a solution of N-(1-(4-formylphenyl)piperidin-4-yl)-N-isopropylacetamide (0.300 g, 1.04 mmol) in DMA (10 mL) was added 2-amino-4,6-dimethoxybenzamide (0.204 g, 1.04 mmol), NaHSO3 (0.129 g, 1.24 mmol) and p-TsOH (0.019 g, 0.10 mmol). The resulting solution was heated to 155° C. overnight and then cooled to room temperature. The solution was diluted with water, extracted with CH2Cl2, washed with brine, dried over anhydrous Na2SO4, filtered, and concentrated in vacuo. The material was purified by flash chromatography on silica gel eluting, with 30% to 100% of 92:7:1 CHCl3/MeOH/concentrated NH4OH in CH2Cl2, to afford the title compound (0.100 g, 20%). 1H NMR (300 MHz, DMSO-d6): mixture of rotamers δ 11.66 (s, 1H), 8.07 (d, J=8.3 Hz, 2H), 6.89-7.15 (m, 2H), 6.67 (s, 1H), 6.46 (s, 1H), 3.90-4.11 (m, 3H), 3.88 (s, 3H), 3.83 (s, 3H), 2.80-3.02 (m, 2H), 2.39-2.66 (m, 1H), 1.92-2.06 (m, 3H), 1.63-1.82 (m, 2H), 1.32-1.47 (m, 1H), 1.21-1.32 (m, 3H), 1.08-1.21 (m, 4H). ESI MS m/z 463 [M−H]−.
