Ethinylestradiol EP Impurity J Catalogue C206540 CAS Ethinylestradiol EP Impurity J M.W 310.44 M.F C21H26O2 Specifications FAQs (8R,9S,13S,14S,17R)-17-ethynyl-1,13-dimethyl-7,8,9,11,12,13,14,15,16,17-decahydro-6H-cyclopenta[a]phenanthrene-3,17-diol