REACTIVITY STUDIES ON NATURAL PRODUCTS: V. RATES OF BOROHYDRIDE REDUCTION OF SOME RING A AND B STEROID KETONES

Abstract

The rates of reduction of 3-, 6-, and 7-cholestanone, coprostan-3-one, Δ⁴- and Δ⁵-cholesten-3-one, and Δ⁸⁽¹⁴⁾-ergosten-3-one with sodium borohydride in isopropanol have been measured. The proportions of α- and β-isomers formed were determined in most cases and the corresponding rates of equatorial and axial reduction obtained. Δ⁵-Cholesten-3-one and 6- and 7-cholestanone are reduced at a slower rate and Δ⁵-cholesten-3-one and Δ⁸⁽¹⁴⁾-ergosten-3-one at a higher rate than the saturated 3-ketosteroids.