Reaction Steps
50.6 mg of EDCI was added to a mixture of 29.1 mg of Boc-hydrazine, 33.7 mg of HOBT, 105 mg of 1′-[(4,8-dimethoxyquinolin-2-yl)carbonyl]-6-(carboxy)spiro[chroman-2,4′-piperidin]-4-one and 2.2 mL of DMF, and the resulting mixture was stirred at room temperature for 14 hours. The reaction mixture was diluted with 15 mL of ethyl acetate, washed with water and aqueous saturated NaHCO3 solution, and dried over sodium sulfate. The residue was purified through silica gel chromatography (2% MeOH/CHCl3) to obtain 119 mg of tert-butyl 2-({1′-[(4,8-dimethoxyquinolin-2-yl)carbonyl]-4-oxospiro[chroman-2,4′-piperidin]-6-yl}carbonyl)hydrazinecarboxylate. 2 mL of 4 N HCl in dioxane was added to 59.1 mg of the product, and stirred at room temperature for 1 hour, and then concentrated. The residue was suspended in 2.5 mL of THF, and 0.049 μL of triethylamine and 24.3 mg of CDI were added thereto at 0° C., and stirred at room temperature for 14 hours. Water was added to the reaction solution, and extracted with chloroform, and the organic layer was dried over sodium sulfate and concentrated. The residue was purified through silica gel thin-layer chromatography (17% MeOH/CHCl3) to obtain the intended compound. 1H-NMR (CDCl3) δ: 8.85 (1H, br s), 8.38 (1H, d, J=2.2 Hz), 7.97 (1H, dd, J=2.2, 8.8 Hz), 7.77 (1H, dd, J=8.5, 1.0 Hz), 7.47 (1H, dd, J=7.8, 8.5 Hz), 7.20 (1H, s), 7.13 (1H, d, J=8.8 Hz), 7.08 (1H, dd, J=1.0, 7.8 Hz), 4.64-4.56 (1H, m), 4.24-4.16 (1H, m), 4.09 (3H, s), 4.03 (3H, s), 3.67-3.58 (1H, m), 3.43-3.34 (1H, m), 2.87 (1H, d, J=16.8 Hz), 2.81 (1H, d, J=16.8 Hz), 2.26-2.18 (1H, m), 2.11-2.04 (1H, m), 2.01-1.87 (2H, m). MS [M+H]+=517.
