IARC Cancer Review: Animal Inadequate Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 6 ,1974,p. 201.(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. 479.(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) ; Human Inadequate Evidence IMEMDT    IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man . 21 ,1979,p. 479.(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)

The Levonorgestrel, with the CAS registry number 797-63-7,is also known as D(-)-13beta-Ethyl-17alpha-ethynyl-17beta-hydroxygon-4-en-3-one. It belongs to the product categories of Pharmaceuticals;Steroid and Hormone. This chemical's molecular formula is C₂₁H₂₈O₂ and molecular weight is 312.45.Its EINECS number is 212-349-8. What's more,Its systematic name is Levonorgestrel. It is a White Solid which is an emergency contraceptive. Levonorgestrel is safe, tolerated and effective in emergency contraception in woman.It is a synthetic progestational hormone with actions similar to those of  and Progesterone about twice as potent as its racemic or (+-)-isomer (NORGESTREL). It is used for contraception, control of menstrual disorders, and treatment of endometriosis.

Physical properties about Levonorgestrel are:
(1)ACD/LogP: 3.92; (2)# of Rule of 5 Violations: 0; (3)ACD/LogD (pH 5.5): 3.92; (4)ACD/LogD (pH 7.4): 3.92; (5)ACD/BCF (pH 5.5): 557.22; (6)ACD/BCF (pH 7.4): 557.22; (7)ACD/KOC (pH 5.5): 3215.19; (8)ACD/KOC (pH 7.4): 3215.18; (9)#H bond acceptors: 2; (10)#H bond donors: 1; (11)#Freely Rotating Bonds: 2; (12)Index of Refraction: 1.571; (13)Molar Refractivity: 90.18 cm³; (14)Molar Volume: 274.3 cm³; (15)Polarizability: 35.75×10^-24 cm³; (16)Surface Tension: 48.3 dyne/cm; (17)Enthalpy of Vaporization: 82.99 kJ/mol; (18)Vapour Pressure: 2.32E-10 mmHg at 25°C; (19)Rotatable Bond Count: 2; (20)Tautomer Count: 8; (21)Exact Mass: 312.20893; (22)MonoIsotopic Mass: 312.20893; (23)Topological Polar Surface Area: 37.3; (24)Heavy Atom Count: 23; (25)Complexity: 609.

People can use the following data to convert to the molecule structure:
(1)SMILES:O=C4\C=C3/[C@@H]([C@H]2CC[C@]1([C@@H](CC[C@]1(C#C)O)[C@@H]2CC3)CC)CC4
(2) InChI:InChI=1/C21H28O2/c1-3-20-11-9-17-16-8-6-15(22)13-14(16)5-7-18(17)19(20)10-12-21(20,23)4-2/h2,13,16-19,23H,3,5-12H2,1H3/t16-,17+,18+,19-,20-,21-/m0/s1 
(3)InChIKey:WWYNJERNGUHSAO-XUDSTZEEBP

Safety information of Levonorgestrel:
When you are using this chemical, please be cautious about it as the following:
It is not only harmful by inhalation, in contact with skin and if swallowed, but also has limited evidence of a carcinogenic effect. So people should not breathe dust. If you want to contact this product, you must wear suitable protective clothing.

Uses of Levonorgestrel:
Levonorgestrel is used in monophasic and triphasic formulations of combined oral contraceptive pills at low doses. It is also used in emergency contraceptive pills (ECPs), both in a combined Yuzpe regimen which includes estrogen, and as a levonorgestrel-only method. This drug has many side effects, including nausea, vomiting, stomach pain, dizziness, breast tenderness, tiredness and weakness, headache, menstrual changes, and diarrhea. It is also a pregnancy hormone drug.