The C / D Ring Union in ŒStrone and Equilenin

THE method of molecular rotation differences which has been applied to other steroid structural problems by Barton1 throws some light on the nature of the C/D ring union in cestrone and equilenin recently discussed by Shoppee2,3 and by Heer and Miescher4,5. The evidence thus obtained, which is given below, when combined with that collected by Shoppee3, indicates that (+)-equilenin and probably (+)-œstrone have the same configuration at the C/D ring union as the androgens, bile acids and sterols. The data available are few, and the conclusions are therefore drawn with reserve.