反应详情

温度

95 °C

To a 2-neck round bottom flask (1 L) equipped with a mechanical stirrer was added ethyl 2-(hydrazinecarboxamido)-4-methylthiazole-5-carboxylate (42.00 g, 172.00 mmol) in anhydrous triethyl orthoformate (393 mL). The yellow reaction mixture was heated at 95° C. for 2 h, and then cooled to ambient temperature. The precipitate was filtered and washed with cold methanol (100 mL) to afford the title compound as a colourless solid (34.9 g, 80%): mp 165-167° C.; 1H NMR (300 MHz, DMSO-d6) δ 12.94 (br, 1H), 9.09 (s, 1H), 4.64 (t, J=7.1 Hz, 2H), 2.98 (s, 3H), 1.67 (t, J=7.1 Hz, 3H); 13C NMR (75 MHz, DMSO-d6) δ 162.3, 157.1, 154.5, 152.3, 133.6, 118.4, 61.9, 17.7, 14.9; MS (ES+) m/z 255.0 (M+1).

1. customTo a 2-neck round bottom flask (1 L) equipped with a mechanical stirrer
2. temperaturecooled to ambient temperature
3. filtrationThe precipitate was filtered
4. washwashed with cold methanol (100 mL)