<unk>  is a synthetic estrane steroid and the C17β phosphoric acid (phosphate) ester of estradiol (estradiol 17β-phosphate) in the form of a polymer. It is also known as estradiol polymer with phosphoric acid or as estradiol 17β-phosphate polymer, as well as estra-1,3,5(10)-triene-3,17β-diol 17β-phosphate polymer. It has been determined via ultracentrifugation that the mean molecular weight of<unk>  corresponds to a chain length of approximately 13 repeat units of estradiol 17β-phosphate.<unk>  is closely related to polyestriol phosphate (Gynäsan, Klimadurin, Triodurin) and polytestosterone phloretin phosphate (never commercialized), which are estriol and testosterone esters in the forms of polymers, respectively. It is also related to polydiethylstilbestrol phosphate (never commercialized), a diethylstilbestrol ester in the form of a polymer. Solubility<unk>  is of very low solubility in water, acetone, chloroform, dioxane, and ethanol, but dissolves readily in bases, especially in aqueous pyridine. Synthesis Like polyphosphates of polyphenols,<unk>  can be prepared from the monomer (in this case estradiol) and phosphoryl chloride. The latter reacts with both the phenolic hydroxyl group in position 3 and the aliphatic one in position 17β. The molecular mass of the resulting polymer can be controlled by interrupting the reaction after a given time: the longer the reaction is allowed to continue, the higher the mass.
Polyestradiol phosphate
Polyestriol phosphate
Progestogen ester
Androgen ester
Progestogen 
Progestogen
Estradiol sulfate
Estrogen ester