反应详情

To a stirred solution of dimsyl sodium, prepared from 43.2 g of NaH (0.90 mol; 50% in oil, washed 3 times with hexane) and 1200 ml of DMSO was added in aliquots, 100 g (0.989 mol) of 4-hydroxypiperidine such that the temperature remained below 23° (using an ice bath). To the mixture was then added dropwise 120 ml (0.99 mol) of p-fluoroacetophenone. The mixture was then stirred at room temperature overnight, poured into water, extracted twice with ether, washed with saturated sodium chloride and dried over potassium carbonate. Filtration followed by evaporation of the solvent provided an oil. The oil was filtered through 500 g of alumina and eluted 2×500 ml of 5% methanol/ether and 2×500 ml of 10% methanol/ether. The material was contained in fractions 2-4. Evaporation of the solvent provided an oil. The yield of the oxalate was 51.2 g (0.165 mol, 18.4%). Recrystallization from methanol provided analytically pure material, m.p. 183- 187.

1. customremained below 23°
2. extractionextracted twice with ether
3. washwashed with saturated sodium chloride
4. dry with materialdried over potassium carbonate
5. filtrationFiltration
6. customfollowed by evaporation of the solvent
7. customprovided an oil
8. filtrationThe oil was filtered through 500 g of alumina
9. washeluted 2×500 ml of 5% methanol/ether and 2×500 ml of 10% methanol/ether
10. customEvaporation of the solvent
11. customprovided an oil
12. customRecrystallization from methanol
13. customprovided analytically pure material