反应详情

To a stirred solution of diamino-3-methoxy-pyridinium salt of 4-nitrobenzoic acid (1 g, 7.14 mmol) in ethanol (10 mL) at 0° C., DBU (2.1 mL) was added followed by 1-formyl-cyclopropanecarboxylic acid ethyl ester (1.5 g, 10.71 mmol). After addition the reaction mixture was stirred at RT for 2 hours. The reaction mixture was concentrated, the obtained residue was diluted with EtOAc (100 mL), washed with water (20 mL×2), brine (20 mL), dried over anhydrous Na2SO4, filtered and concentrated. The crude was purified by silica gel column chromatography (using 0 to 15% EtOAc in CH2Cl2 as eluent) to afford the title compound (800 mg, 53%, white solid). 1H NMR (400 MHz, CDCl3): δ=8.18-8.16 (d, J=6.4 Hz; 1H), 6.89 (t, J=7.2 Hz, 1H), 6.76 (d, J=8 Hz; 1H), 4.20-4.14 (m, 2H), 4.03 (s, 3H), 1.73-1.70 (m, 2H), 1.59-1.56 (m, 2H), 1.20 (t, J=6.8 Hz; 3H) ppm.

1. additionAfter addition the reaction mixture
2. concentrationThe reaction mixture was concentrated
3. additionthe obtained residue was diluted with EtOAc (100 mL)
4. washwashed with water (20 mL×2), brine (20 mL)
5. dry with materialdried over anhydrous Na2SO4
6. filtrationfiltered
7. concentrationconcentrated
8. customThe crude was purified by silica gel column chromatography (using 0 to 15% EtOAc in CH2Cl2 as eluent)