Cytestrol acetate

Cytestrol acetate

Clinical data
Synonyms	11α-Hydroxyethinylestradiol 3-(bis(2-chloroethyl)carbamate) 11α,17β-diacetate; 17α-Ethynylestra-1,3,5(10)-triene-3,11α,17β-triol 11α,17β-diacetate 3-(bis(2-chloroethyl)carbamate)
Identifiers
IUPAC name (1S,10S,11S,14R,15S,17R)-17-(Acetyloxy)-5-{[bis(2-chloroethyl)carbamoyl]oxy}-14-ethynyl-15-methyltetracyclo[8.7.0.0²,⁷.0¹¹,¹⁵]heptadeca-2,4,6-trien-14-yl acetate
ChemSpider	58838619
Chemical and physical data
Formula	C29H35Cl2NO6
Molar mass	564.50 g·mol−1
3D model (JSmol)	Interactive image
SMILES [H][C@@]12CC[C@@](OC(C)=O)(C#C)[C@@]1(C)C[C@@H](OC(C)=O)[C@]1([H])C3=CC=C(OC(=O)N(CCCl)CCCl)C=C3CC[C@@]21[H]
InChI InChI=1S/C29H35Cl2NO6/c1-5-29(38-19(3)34)11-10-24-23-8-6-20-16-21(37-27(35)32(14-12-30)15-13-31)7-9-22(20)26(23)25(36-18(2)33)17-28(24,29)4/h1,7,9,16,23-26H,6,8,10-15,17H2,2-4H3/t23-,24-,25+,26+,28-,29-/m0/s1 Key:RRJRVDYYFLBGSE-UPRLNUCLSA-N

Cytestrol acetate is a steroidal antiestrogen and an alkylating antineoplastic agent (i.e., chemotherapeutic) which was developed for the treatment of breast cancer but was never marketed. It is an 11α-hydroxylated derivative of ethinylestradiol in which a bis(2-chloroethyl)amine nitrogen mustard moiety has been attached as an ester at the C3 position and acetate esters have been attached at the C11α and C17β positions. The mechanism of action of cytestrol acetate in breast cancer is two-fold: (1) acting as an antiestrogen similarly to fulvestrant or ICI-164384; and (2) having cytostatic actions via the alkylating nitrogen mustard moiety analogously to estramustine phosphate. The drug shows potent efficacy against breast cancer superior to that of tamoxifen in in vitro models.