Part I: 4-oxasteroids. Part II: Extractives of euphorbia pulcherimma.

As part of a general investigation into the effects of changes in the basic carbon skeleton of steroids on their physiological and chemical properties, a number of androstane and cholestane derivatives having an oxygen in place of a carbon at the 4-position have been prepared since 1950. Turner (1) obtained by catalytic hydrogenation of 5-oxo-3,5- seco-A-norcholestane-3-oic acid (lIa) (2), two lactones, m.p. 116-116.5°C and m.p. 109.5-110°C, the latter in large amount. He provisionally assigned to these compounds the structures IXa and VIIIa respectively because of their optical rotations and because hydrogenation of 4- oxacholest-5-en-3-one (IIIa) (3), which should be expected to give lactone IXa, gave the higher melting isomer