反应详情

To a solution (60 ml) of 6α-methylpredonisolone (6α-methyl-11β,17α,21-trihydroxy-1,4-pregnadiene-3,20-dione) (12) (2.13 g ) in dichloromethane were added pyridinium p-toluenesulfonate (28.0 mg) and trimethyl orthoacetate (1.01 ml). The mixture was stirred at room temperature (20°-25° C.) for 5 hours. When the reaction was completed, the reaction mixture was concentrated, and the residue was dissolved in acetone. (30 ml). While cooling the mixture on ice, an aqueous solution (30 ml) of p-toluenesulfonic acid.H2O (1.19 g) was added thereto. The mixture was stirred for 30 minutes on ice. Upon completion of reaction, a saturated aqueous NaHCO3 solution was added and extraction was performed using ethyl acetate. After steps of washing with brine, drying over Na2SO4, evaporation of the solvent, and silica gel column chromatography (silica gel, 40 g) using 50% ethyl acetate/hexane as eluant, 17α-acetoxy-11β,21-dihydroxy-6α-methyl-1,4-pregnadiene-3,20-dione (13) (2.11 g, 89%) was obtained.

1. concentrationthe reaction mixture was concentrated
2. dissolutionthe residue was dissolved in acetone
3. temperatureWhile cooling the mixture on ice
4. additionH2O (1.19 g) was added
5. stirringThe mixture was stirred for 30 minutes on ice
6. customUpon completion of reaction
7. extractionextraction
8. washAfter steps of washing with brine
9. dry with materialdrying over Na2SO4, evaporation of the solvent, and silica gel column chromatography (silica gel, 40 g)