The invention provides compounds of formula I, II, III, or IV: ##STR00001##
wherein R.sup.1 to R.sup.11, X, and Y have any of the values defined in the specification. The compounds inhibit Na, K-ATPase 4 and are useful as contraceptive agents.

The invention provides compounds of formula I, II, III, or IV: ##STR00001##
wherein R.sup.1 to R.sup.11, X, and Y have any of the values defined in the specification. The compounds inhibit Na, K-ATPase 4 and are useful as contraceptive agents.

Chemical entities that are novel compounds, pharmaceutical compositions and methods of treatment of cancer are described.