反应详情

温度

90 °C

A mixture of 3-hydroxy-4,5,6,7-tetrahydro-1,2-benzisothiazole 22a (4.74 g), pyridinium hydrochloride (12.7 g), phosphoric acid (2.1 g) and phosphorus oxychloride (25 mL) was stirred at 90° C. for 5 h. The reaction mixture was evaporated and ethyl acetate (130 mL) was added to the residue. A saturated solution of sodium hydrogencarbonate (130 mL) was added and after 10 min of stirring the phases were separated. The aqueous phase was extracted with ethyl acetate (2×150 mL) and the combined organic phases were dried and evaporated to give an oil. Column chromatography on silica gel (eluent:toluene-ethyl acetate 1:1) gave the title compound as a yellow oil (2.8 g).

1. customThe reaction mixture was evaporated
2. additionethyl acetate (130 mL) was added to the residue
3. additionA saturated solution of sodium hydrogencarbonate (130 mL) was added and after 10 min
4. stirringof stirring the phases
5. customwere separated
6. extractionThe aqueous phase was extracted with ethyl acetate (2×150 mL)
7. customthe combined organic phases were dried
8. customevaporated
9. customto give an oil