反应详情

A mixture of 3-phenyl-1H-pyrazol-5-ol (8.80 g, 0.055 mol), 1-bromo-3-chloropropane (9.5 g, 1.1 eq, 0.06 mol) and potassium carbonate (30.3 g, 4 eq, 0.22 mol) in acetonitrile (120 mL) is heated for 5.5 h under reflux. Thereafter the volatiles are evaporated and the residue is treated with 50 mL ethyl acetate. The residual solid is washed 2× with ethyl acetate and the combined organic phases are evaporated. The obtained crude product is triturated with methyl tert butylether and 6.4 g (53%) of 2-phenyl-6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine are obtained as solid.

1. temperatureis heated for 5.5 h
2. temperatureunder reflux
3. customThereafter the volatiles are evaporated
4. additionthe residue is treated with 50 mL ethyl acetate
5. washThe residual solid is washed 2× with ethyl acetate
6. customthe combined organic phases are evaporated
7. customThe obtained crude product
8. customis triturated with methyl tert butylether and 6.4 g (53%) of 2-phenyl-6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine
9. customare obtained as solid