反应详情

A mixture of methyl 4-(2-nitrovinyl)benzoate (18.6 g, 90 mmol), paraformaldehyde (3.2 g, 108 mmol) and 10% Pd/C (0.9 g) in the mixture of methanol (220 mL) and tetrahydrofuran (220 mL) was stirred at room temperature over 1 atm of hydrogen for 3 h. Then the mixture was filtered and evaporated, purified by column chromatography (silica gel, petroleum ether/ethyl acetate 15:1 to 8:1) to obtain methyl 4-(2-(hydroxyimino)ethyl)benzoate (3.6 g, yield 21%) as yellow solid. 1H-NMR (400 MHz, DMSO-d6) δ (ppm): 3.55-3.56 (d, J=6.0 Hz, 0.5H), 3.69-3.71 (d, J=5.2 Hz, 1.5H), 3.84 (s, 3H), 6.84-6.87 (t, J=5.6 Hz, 0.75H), 7.45-7.47 (t, J=6.2 Hz, 0.25H), 7.37-7.41 (m, 2H), 7.90-7.91 (m, 2H), 10.68 (s, 0.25H), 11.14 (s, 0.75H); LC-MS (ESI) m/z: 194 (M+1)+.

1. filtrationThen the mixture was filtered
2. customevaporated
3. custompurified by column chromatography (silica gel, petroleum ether/ethyl acetate 15:1 to 8:1)