11beta-Trimethylsiloxy-21-acetoxy-6alpha-fluoropregna-4,16-diene-3,20-dione → 11beta-Trimethylsiloxy-21-acetoxy-6alpha-fluoropregna-1,4,16-triene-3,20-dione

Participants

Reaction Steps

A mixture of 3.5 g of 11β-trimethylsiloxy-21-acetoxy-6α-fluoropregna-4,16-diene-3,20-dione obtained according to Example 6, 2.65 g of 2,3-dichloro-4,5-dicyanobenzoquinone (DDQ) and 30 ml of dioxan was heated under reflux for 2 hours. The resulting dark colored suspension was cooled, filtered from dichloro-dicyanohydroquinone, and evaporated to dryness. The residue was dissolved in chloroform and passed through a short column of neutral alumina (50 g). The solvent was evaporated under reduced pressure. The residue was crystallized from methanol. The analytical sample of 11β-trimethylsiloxy-21-acetoxy-6α-fluoropregna-1,4,16-triene-3,20-dione (compound 13) was obtained by an additional recrystallization from methanol. The yield was 2.65 g.

Provenance & Evidence