IUPAC Name: (8R,9S,13S,14S,17R)-17-Ethynyl-13-methyl-7,8,9,11,12,14,15,16-octahydro-6H-cyclopenta[a]phenanthrene-3,17-diol
Molecular Weight: 296.40336 [g/mol]
Molecular Formula: C₂₀H₂₄O₂
XLogP3: 3.7
H-Bond Donor: 2
H-Bond Acceptor: 2 
EINECS: 200-342-2
Product Categories: Alcohols and Derivatives; Steroids; Acetylenes; Biochemistry; Functionalized Acetylenes; Hydroxysteroids; Intermediates & Fine Chemicals; Metabolites & Impurities; Pharmaceuticals 
Refractive index: -30 ° (C=0.4, Pyridine)
Solubility: ethanol: 50 mg/mL, clear, slightly yellow 
Index of Refraction: 1.623
Molar Refractivity: 86.26 cm³
Molar Volume: 244.4 cm³
Surface Tension: 57.2 dyne/cm
Density: 1.21 g/cm³
Flash Point: 211.2 °C
Enthalpy of Vaporization: 75.58 kJ/mol
Boiling Point: 457.2 °C at 760 mmHg
Vapour Pressure: 3.74E-09 mmHg at 25 °C
Appearance: Off-White to Light-Yellow Crystalline Powder
Melting Point: 182-183 °C(lit.)
Classification Code of Ethynyl estradiol (CAS NO.57-63-6): Drug / Therapeutic Agent; Estrogen; Estrogens; Hormone; Hormones; Hormones, Hormone Substitutes, and Hormone Antagonists; Human Data; Mutation data; Reproductive Effect; Tumor data

The first orally active semisynthetic steroidal estrogen, Ethynyl estradiol (CAS NO.57-63-6), the 17alpha-ethynyl analog of estradiol, was synthesized in 1938 by Hans Herloff Inhoffen and Walter Hohlweg at Schering AG in Berlin. It was approved by the FDA in the U.S. on June 25, 1943 and marketed by Schering as Estinyl. The FDA withdrew approval of Estinyl effective June 4, 2004 at the request of Schering, who had discontinued marketing Estinyl.

 Ethynyl estradiol (CAS NO.57-63-6) is used as a female hormone class medicine. It is a synthetic steroid with high oral estrogenic potency.

NTP 10th Report on Carcinogens. IARC Cancer Review: Human Limited Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 21 , 1979,p. 233.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; Animal Sufficient Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 6 , 1974,p. 77.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) ; IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 21 , 1979,p. 233.(World Health Organization, Internation Agency for Research on Cancer,Lyon, France.: ) (Single copies can be ordered from WHO Publications Centre U.S.A., 49 Sheridan Avenue, Albany, NY 12210) . Reported in EPA TSCA Inventory.

Hazard Codes: T
Risk Statements: 45-22
45:May cause cancer 
22:Harmful if swallowed 
Safety Statements: 53-36/37/39-45
53:Avoid exposure - obtain special instruction before use 
36/37/39:Wear suitable protective clothing, gloves and eye/face protection 
45:In case of accident or if you feel unwell, seek medical advice immediately (show label where possible 
WGK Germany: 3
RTECS: RC8925000
Confirmed carcinogen with experimental carcinogenic, tumorigenic, and neoplastigenic data. Poison by intraperitoneal route. Moderately toxic by ingestion. Human systemic effects by ingestion: glandular effects. An experimental teratogen. Experimental reproductive effects. Human mutation data reported. When heated to decomposition it emits acrid smoke and irritating fumes.

  Ethynyl estradiol (CAS NO.57-63-6), its Synonyms are (17-alpha)-19-Norpregna-1,3,5(10)-trien-20-yne-3,17,diol ; 17-Ethinyl-3,17-estradiol ; 17-Ethinyl-3,17-oestradiol ; 17-Ethinylestradiol ; 17-Ethynyl-3,17-dihydroxy-1,3,5-oestratriene ; 17-Ethynylestradiol ; 17-Ethynyloestradiol ; 17-alpha-Ethinyl-17-beta-estradiol ; 17-alpha-Ethinyl-3,17-dihydroxy-delta(sup 1,3,5)-estratriene ; Aethinyloestradiolum ; Aethinyoestradiol ; Estorals ; Estra-1,3,5(10)-triene-3,17-beta-diol, 17-alpha-ethynyl- ; Estra-1,3,5(10)-triene-3,17beta-diol, 17alpha-ethynyl- ; Estradiol, 17-ethynyl- ; Ethidol ; Ethinoral ; Primogyn C ; Primogyn M ; Progynon C ; Spanestrin .