Water → HCID 57286567, compound

Participants

Reaction Steps

A solution of 2.67 g (8.1 mmol) of (20R)-1α,2α-epoxy-20-hydroxy-pregna-4,6-dien-3-one in 120 ml of benzene is concentrated to 60 ml in a water-jet vacuum at 40° C., cooled to room temperature and to the suspension are added 1.6 ml of 3,4-dihydro-2H-pyran as well as 16 mg of anhydrous p-toluenesulphonic acid. The mixture is stirred at room temperature for 2.5 hours. The resulting solution is diluted with ether, washed with saturated sodium hydrogen carbonate solution and then with saturated sodium chloride solution, dried over sodium sulphate and evaporated. There are obtained 3.3 g of crystalline (20R)-1α,2α-epoxy-20-[(tetrahydro-2H-pyran-2-yl)oxy]-pregna-4,6-dien-3-one. Recrystallisation from ether containing 0.1% triethylamine yields colourless prisms of melting point 139°-140° C.; [α]D25 =+233.6° (c=0.5 in chloroform), UV (ethanol): λmax 291 nm (ε=20940).

Provenance & Evidence