p-Toluenesulfonic acid → 13-Ethinyl-3-ethoxy-10-methyl-gona-3,5-dien-17-one

Participants

Reaction Steps

A mixture of 1.2 g of 13-ethinyl-10-methyl-gon-4-ene-3,17-dione, 20 ml of dioxane, 2 ml of orthoformic acid ethyl ester and 60 mg of p-toluenesulphonic acid is stirred at room temperature for 3 3/4 hours with exclusion of light. The reaction mixture is poured into 150 ml of water containing 5 drops of pyridine and extracted twice with ethyl acetate and the organic layer is washed with water and saturated sodium chloride solution until neutral, dried and evaporated in a water pump vacuum. The crystalline crude 13-ethinyl-3-ethoxy-10-methyl-gona-3,5-dien-17-one, which is obtained, is then dissolved in 20 ml of dioxane and the solution is added dropwise, in the course of 30 minutes, to a solution, which is saturated with acetylene, of 6 g of a lithium acetylide/ethylenediamine complex in 60 ml of dioxane, whilst passing acetylene through the mixture at the same time. The reaction mixtue is then stirred for a further 15 minutes at room temperature and treated, whilst cooling, with saturated ammonium chloride solution and with ethyl acetate and the organic phase is washed successively with 1 N hydrochloric acid and saturated sodium chloride solution, dried and evaporated in a water pump vacuum.

Provenance & Evidence