Water → HCID 86738156, compound

Participants

Reaction Conditions

Reaction Steps

A solution of 3.42 g (10 mmol) of (20S)-1α,2α-epoxy-21-hydroxy-20-methyl-pregna-4,6-dien-3-one in 100 ml of toluene is concentrated to 50 ml in a water-jet vacuum. The resulting suspension is treated at 0° C. with 2 ml of a suspension prepared from 50 ml of toluene, 0.172 g of p-toluenesulphonic acid and 0.2 ml of pyridine. Thereafter 3 ml of isopropenyl methyl ether are added and the resulting mixture is stirred at 0° C. for 3 hours. After the addition of 1 ml of triethylamine, the mixture is concentrated at 30° C./11 Torr. The crystalline residue is dissolved in a small amount of methylene chloride containing 0.1% triethylamine and treated with ether to give 2.91 g (70%) of (20S)-1α,2α-epoxy-21-(1-methoxy-1-methylethoxy)-20 -methyl-pregna-4,6-dien-3-one of melting point 150°-151° C.; [ α]D25 =+185.8° C. (c=1.0 in chloroform containing 0.1% triethylamine).

Provenance & Evidence