反应详情

1-(3-Hydroxypropyl)piperazin-2-one (700 mg, 4.43 mmol) in formic acid (10 ml) and 37/40% aqueous formaldehyde solution (5 ml) was stirred and heated at 95° for 2 hr then the resulting solution evaporated in vacuo. The residue was taken up in 5% methanol in dichloromethane (20 ml), basified with a 7N solution of ammonia in methanol and stirred 4.5 hr at room temperature. The mixture was filtered and the filtrate purified by column chromatography on silica using increasing concentrations of methanolic ammonia in dichloromethane as eluent to give 1-(3-hydroxypropyl)-4-methylpiperazin-2-one (710 mg, 93%) as a colourless oil; NMR Spectrum:(CDCl3) 1.73 (quintet, 2H), 2.34 (s, 3H), 2.66 (t, 2H), 3.13 (s, 2H), 3.33 (t, 2H), 3.53 (m, 4H), 3.80 (s(broad, 1H).

1. temperatureheated at 95° for 2 hr
2. customthe resulting solution evaporated in vacuo
3. filtrationThe mixture was filtered
4. customthe filtrate purified by column chromatography on silica using
5. temperatureincreasing concentrations of methanolic ammonia in dichloromethane as eluent