1,9-Cyclo-19-nor-1,2-secoergostan-2-oicacid, 6,7-epoxy-22,24,25-[ethylidynetris(oxy)]-5,11-dihydroxy-12-oxo-, g-lactone, [5a,6a,7a,9b,10a,11b,22R(S)]-