反应详情

A 250-mL round-bottom flask was charged with a solution of (E)-benzyl 3-(3-(dimethylamino)acryloyl)piperidine-1-carboxylate (19 g, 54.05 mmol, 1.00 equiv, 90%) in ethanol (100 mL). To this was added conc.HCl (3 mL, 36%) drop wise and allowed to stir for 10 minutes. Then, to the resulting mixture was added NH2NH2.H2O (60 mL, 80%) and refluxed overnight. The progress was monitored by TLC (EtOAc:PE=1:1). Upon completion, the resulting mixture was concentrated on a rotary evaporator and diluted with H2O (200 mL). The mixture was extracted with ethyl acetate (3×200 mL). Combined organic layers were dried over anhydrous magnesium sulfate, filtered off and concentrated on a rotary evaporator affording a residue that was purified by a silica gel column chromatography eluted with ethyl acetate/petroleum ether (2:3) to give benzyl 3-(1H-pyrazol-5-yl)piperidine-1-carboxylate as colorless oil (13 g, 80%).

1. additionTo this was added conc
2. temperaturerefluxed overnight
3. concentrationUpon completion, the resulting mixture was concentrated on a rotary evaporator
4. additiondiluted with H2O (200 mL)
5. extractionThe mixture was extracted with ethyl acetate (3×200 mL)
6. dry with materialCombined organic layers were dried over anhydrous magnesium sulfate
7. filtrationfiltered off
8. concentrationconcentrated on a rotary evaporator
9. customaffording a residue that
10. customwas purified by a silica gel column chromatography
11. washeluted with ethyl acetate/petroleum ether (2:3)