REACTIVITY STUDIES ON NATURAL PRODUCTS: IV. DISSOCIATION CONSTANTS OF THE CYANOHYDRINS OF SOME STEROID KETONES

Abstract
The dissociation constants of the cyanohydrins of 3-, 6-, and 7-ketocholestane, 3-ketocoprostane, Δ4- and Δ5-cholestenone, and Δ7-, Δ8(9)-, Δ8(14)-, and Δl4-ergosten-3-one have been measured in 80% dioxane at 25.0°. Cholestan-3-one and coprostan-3-one have essentially the same reactivity. 6- and 7-Ketocholestane show "eclipsing" effects of neighboring hydrogen atoms. Δ4- and Δ5-Cholestenone are less reactive than cholestanone owing to the electronic effect of the double bond, but Δ7-, Δ8(9)-, Δ8(14)-, and Δl4-ergostenone are more reactive, the effect decreasing with the distance of the double bond from the 3-keto group.