反应详情

Under nitrogen, a solution of 1.2 g (5 mmol) of imidate ester from step 6 and 850 mg (5 mmol) of N2 -butyl valeric acid hydrazide from step 2 in 25 mL of absolute methanol was stirred for 24 h at ambient temperature. The methanol was removed in vacuo and replaced with 25 mL of anhydrous toluene. The reaction vessel was equipped with a Dean-Stark trap and the reaction stirred at reflux for 48 h. Concentration in vacuo produced the crude product residue. Purification by silica gel chromatography (Waters Prep-500A) using ethyl acetate/hexane (60:40) gave 700 mg (40%) of 2-bromo-5-[(1, 3-dibutyl-1H-1,2,4-triazol-5-yl)methyl]pyridine as an oil: NMR (CDCl3) δ 0.88 (t, J=7Hz, 3H), 0.92 (t, J=7Hz, 3H), 1.25-1.75 (m, 8H), 2.67 (t, J=8Hz, 2H), 3.93 (t, J= 7Hz, 2H), 4.05 (s, 2H), 7.43 (s, 1H), 7.44 (s, 1H), 8.27 (s, 1H); MS (FAB)m/e (rel intensity) 353 (50), 351 (50), 297 (100), 295 (100), 215 (40), 160 (90), 158 (90), 138 (70).

1. customThe methanol was removed in vacuo
2. customThe reaction vessel was equipped with a Dean-Stark trap
3. temperatureat reflux for 48 h
4. concentrationConcentration in vacuo
5. customproduced the crude product residue
6. customPurification by silica gel chromatography (Waters Prep-500A)