反应详情

23.9 g (55 mmol) of a mixture of methoxymethyltriphenylphosphonium bromide and sodium amide are covered with a layer of 145 ml of anhydrous tetrahydrofuran and the mixture is stirred vigorously for 15 min. 17.4 g (55 mmol) of the compound from Example V are added to 145 ml of tetrahydrofuran and the mixture is stirred at room temperature for 1 h. A further 23.9 g (55 mmol) of methoxymethyltriphenylphosphonium bromide/sodium amide are added and the mixture is stirred at room temperature for 60 min. 185 ml (1.11 mol) of 6 M hydrochloric acid are added, and the mixture is heated to reflux for 1 h and cooled. It is neutralized using 5 M sodium hydroxide solution and the phases are separated. The aqueous phase is extracted twice with ethyl acetate, and the combined organic phases are washed with saturated sodium chloride solution, dried over sodium sulphate and concentrated to dryness. The residue which remains is dissolved in dichloromethane and added to a glass frit (porosity 3) which contains 450 g of silica gel 230-400 mesh. The mixture is eluted without sucking dry using a gradient of petroleum ether/ethyl acetate of 4:1 to 2:1. The eluate is concentrated to dryness in vacuo and the residue is thoroughly stirred in a mixture of ether/petroleum ether. Yield: 13.8 g (80% of theory) of colorless crystals M.p.: 187° C.

1. stirringthe mixture is stirred at room temperature for 1 h
2. stirringthe mixture is stirred at room temperature for 60 min
3. temperaturethe mixture is heated
4. temperatureto reflux for 1 h
5. temperaturecooled
6. customthe phases are separated
7. extractionThe aqueous phase is extracted twice with ethyl acetate
8. washthe combined organic phases are washed with saturated sodium chloride solution
9. dry with materialdried over sodium sulphate
10. concentrationconcentrated to dryness
11. dissolutionThe residue which remains is dissolved in dichloromethane
12. additionadded to a glass frit (porosity 3) which
13. washThe mixture is eluted
14. customwithout sucking dry
15. concentrationThe eluate is concentrated to dryness in vacuo
16. stirringthe residue is thoroughly stirred in a mixture of ether/petroleum ether