A. V. Kamernitskii

Optical rotatory dispersion and circular dicheoism in structueal and sterecchemical problems Communication 6. Study of the stereochemistry of the side chain of 21-substituted δ16(17)-20-ketopregnenes

1. The Δ16(17)-20-keto group in 21-substituted pregnetiones is conformationally labile. 2. From a comparison of the IR, UV, and CD spectra, the influence of substitution at C-21 on the configuration of theα, β-unsaturated ketochromophore was established.

Transformed steroids Communication 58. Epoxidation of divinyl ketones of steroid series

1. A study was made of the oxidation of divinyl ketones of the steroid series with alkaline hydrogen peroxide in various solvents: the most suitable variation for preparing the diepoxides is epoxidation in dioxane. Running the reaction in methanol yields a complex mixture of compounds, the main component of which is 16α,17α;-epoxy-21-methoxymethylpregn-5-en-3Β-ol-20-one 3-acetate (IV), the product of the primary addition of CH3OH to the more reactive unsubstituted δ21 bond and subsequent epoxidation of the δ16 bond. The formation of a noticeable amount of 16α,17α-epoxy-21-homopregna-5,21-dien-3/gb-ol-20-one 3-aeetate is observed after chromatographing on florisil. 2. 16α,17α-Epoxy-21-alkoxymethylpregn-4-ene-3,20-diones (XIIIa-c) were obtained by two methods.

Transformed steroids Communication 57. Use of the mannich reaction to build up the side chain of steroids

1. A steroidal divinyl ketone, namely 21-homopregna-5,16,21-trien-3β-ol-20-one 3-acetate (III), the starting product in the synthesis of polyhydroxy steroids, was synthesized in 64% yield by starting with the readily-available dehydropregnenolone acetate via the Mannich reaction and subsequent cleavage. 2. A siudy was made of the reactivity of the conjugated bonds in divinyl ketone (III) under the conditions of hydration and the addition of alcohols in acid and alkaline media.