Ammonium Chloride → 11beta-Trimethylsiloxy-21-acetoxy-6alpha-fluoro-16alpha-methyl-pregna-1,4-diene-3,20-dione

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Reaction Conditions

Reaction Steps

750 mg cuprous iodide was suspended in 10 ml dichloromethane in an atmosphere of nitrogen and cooled to -10° C. To this suspension under stirring and cooling was added 9 ml of a 2% solution of lithium-methyl by drop wise addition maintaining the temperature below -5°. To the so obtained lithium-dimethyl-copper solution was added 425 mg 11β-trimethylsiloxy-21-acetoxy-6α-fluoropregna-1,4,16-triene-3,20-dione obtained according to Example 8 dissolved in 3 ml dichloromethane. The temperature of the reaction mixture was kept below -1°, and the stirring was maintained for a period of 15 minutes. The reaction mixture was poured into an aqueous ammonium chloride solution, the organic phase separated and the aqueous phase re-extracted with dichloromethane. The organic extracts were combined, washed with water, dried over anhydrous sodium sulfate and concentrated to dryness under reduced pressure. Trituration with acetone afforded a crystalline product 11β-trimethylsiloxy-21-acetoxy-6α-fluoro-16α-methyl-pregna-1,4-diene-3,20-dione (compound 14) yield 320 mg TLC: homogeneous.

Provenance & Evidence