反应详情

59.0 g (0.308 mole) of (I) is taken up in dry dioxane (800 ml) and purged with HCl gas at 70° for 5 hours. Solvent is removed, the residue is azeotropically distilled three times with benzene and the residue taken up in dimethoxyethane (200 ml) and water (22 ml). After standing overnight at room temperature, the reaction mixture is evaporated to dryness, taken up in ethyl acetate (1.5 liters) and washed twice with saturated NaHCO3 solution (630 ml portions). The NaHCO3 phase is back-washed with ethyl acetate (1.0 liter), the organic extracts are combined and washed 3 times with 500 ml portions of water. The organic layer is evaporated. The solid obtained is taken up in acetone (1.0 liter), charcoaled and evaporated. The product is recrystallized from benzene (500 ml) and petroleum ether (650 ml). Yield: 20.7 g, percent yield: 36.9%, single spot, Rf 0.30 (alumina, CHCl3 :EtOAc-6:4). mp=129°-131° (crude); mp on recrystallization: 135°-136°.

1. custompurged with HCl gas at 70° for 5 hours
2. customSolvent is removed
3. distillationthe residue is azeotropically distilled three times with benzene
4. customthe reaction mixture is evaporated to dryness
5. washwashed twice with saturated NaHCO3 solution (630 ml portions)
6. washThe NaHCO3 phase is back-washed with ethyl acetate (1.0 liter)
7. washwashed 3 times with 500 ml portions of water
8. customThe organic layer is evaporated
9. customThe solid obtained
10. customevaporated
11. customThe product is recrystallized from benzene (500 ml) and petroleum ether (650 ml)
12. custommp on recrystallization
13. custom135°-136°