反应详情

ethyl propiolate (804 mg) was added to the o-xylene (15 mL) solution of tetrahydropyridino[1,2-c][1,2,3]oxadiazolone (1.04 g) under a nitrogen atmosphere and refluxed for 16 h. The solution was concentrated under a reduced pressure. The residue was applied to silica gel column chromatography, then the column was eluted with n-hexane-AcOEt (2/1–1/1). The titled compound was obtained as yellow oil (871 mg, 65%), and 4,5,6,7-tetrahydropyrazolo[1,5-a]pyridine-3-carboxylic acid ethyl ester was obtained as yellow oil (345 mg, 26%).

1. temperaturerefluxed for 16 h
2. concentrationThe solution was concentrated under a reduced pressure
3. washthe column was eluted with n-hexane-AcOEt (2/1–1/1)