反应详情

Under nitrogen, a sclution of 53.8 g (1.68 mol) of anhydrous hydrazine in 300 mL of methanol was cooled to 0° C. and treated with 186 g (1.4 mol) of methyl 4-methylvalerate. The reaction was allowed to warm to ambient temperature and stir overnight prior to stirring at reflux for 4 h. The reaction was concentrated in vacuo giving 166 g (93%) of 4-methylvaleric acid hydrazide as a colorless solid: 49°-51° C.; NMR (CDCl3) δ 0.89 (d, J=7 Hz, 6H), 1.48-1.64 (m, 3H), 2.15 (t, J=7 Hz, 2H), 3.91 (br s, 2H), 6.94 (br s, 1H). A 7.86 g (60 mmol) sample of the hydrazide was dissolved in 50 mL of methanol and treated with 7.8 g (60 mmol) of ethyl iminovalerate under nitrogen. The reaction was stirred at reflux overnight and concentrated in vacuo. Purification by silica gel chromatography (Waters Prep-500A) using ethyl acetate/hexane (40:60) gave 9.6 g (82%) of 3-butyl-5-isopentyl-1H-1,2,4-triazole as a colorless solid which melts close to ambient temperature: NMR (CDCl3) δ 0.81- 0.90 (m, 9H), 1.25-1.40 (m, 2H), 1.47-1.74 (m, 5H), 2.70 (t, J=7 Hz, 4H); MS (FAB) m/e (rel intensity) 196 (100); HRMS. Calcd for M+H: 196.1814. Found: 196.1832.

1. stirringto stirring
2. temperatureat reflux for 4 h
3. concentrationThe reaction was concentrated in vacuo