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Home> Encyclopedia >Pharmaceutical Intermediates>Pharmaceutical>Organic Intermediate
Ulipristal Acetate structure
Ulipristal Acetate structure

Ulipristal Acetate

Iupac Name:[(8S,11R,13S,14S,17R)-17-acetyl-11-[4-(dimethylamino)phenyl]-13-methyl-3-oxo-1,2,6,7,8,11,12,14,15,16-decahydrocyclopenta[a]phenanthren-17-yl] acetate
CAS No.: 126784-99-4
Molecular Weight:475.629
Modify Date.: 2022-11-22 21:49
Introduction: Ulipristal acetate (UPA) is a selective progesterone receptor modulator. Attributing to its higher efficacy and a similar rate of side effects compared to levonorgestrel emergency contraception, it is now recommended as first line treatment for emergency contraception. Emergency contraception is defined as the use of drug or device after unprotected or under-protected intercourse to prevent an unwanted pregnancy. Ulipristal acetate can be used up to 5 days (120 h) after unprotected sexual intercourse.As progesterone promotes the growth of uterine fibroids, the blocking characteristic of ulipristal acetate can thereby be used to reduce the size of uterine fibroids. Ulipristal acetate has also shown efficacy with a significant reduction in uterine bleeding caused by uterine fibroids. The treatment of fibroids by ulipristal acetate should begin in the first week of a menstrual period.Drugs or herbal products that induce enzymes, including CYP3A4, such as carbamazepine, phenytoin, rifampin, St. John's Wort, etc., may decrease the plasma concentrations of ulipristal acetate, and may decrease its effectiveness while CYP3A4 inhibitors such as itraconazole, ketoconazole, etc., may increase plasma concentrations of ulipristal acetate.The half-life after oral intake is 32 h; it binds to plasma proteins for 97–99%, and it is metabolized by the citochrome P450. View more+
1. Names and Identifiers
1.1 Name
Ulipristal Acetate
1.2 Synonyms

(11b)-17-(Acetyloxy)-11-[4-(dimethylamino)phenyl]-19-norpregna-4,9-diene-3,20-dione (11Β)-11-[4-(Dimethylamino)phenyl]-3,20-dioxo-19-norpregna-4,9-dien-17-yl acetate (11Β)-17-(Acetyloxy)-11-(4-(dimethylamino)phenyl)-19-norpregna-4,9-diene-3,20-dione [(8S,11R,13S,14S,17R)-17-acetyl-11-[4-(dimethylamino)phenyl]-13-methyl-3-oxo-1,2,6,7,8,11,12,14,15,16-decahydrocyclopenta[a]phenanthren-17-yl] acetate 17α-Acetoxy-11β-(4-dimethylaminophenyl)-19-norpregna-4,9-dien-3,20-dione 19-Norpregna-4,9-diene-3,20-dione, 17-(acetyloxy)-11-(4-(dimethylamino)phenyl)-, (11Β)- CBD 2914 CDB-2914 Ella Estra-4,9-dien-3-one, 17-acetyl-17-(acetyloxy)-11-[4-(dimethylamino)phenyl]-, (11Β,17α)- HRP 2000 Ulipristal Ulipristal (acetate) Ulipristal acetate/CDB2914 VA 2914 VA2914

1.3 CAS No.
1.4 CID
1.6 Molecular Formula
C30H37NO4 (isomer)
1.7 Inchi
1.8 InChkey
1.9 Canonical Smiles
1.10 Isomers Smiles
2. Properties
2.1 Density
2.1 Melting point
183-185 °C
2.1 Boiling point
640.1 °C at760mmHg
2.1 Refractive index
2.1 Flash Point
340.9 °C
2.1 Precise Quality
2.1 PSA
2.1 logP
2.1 Appearance
White to Yellow to Green powder to crystal
2.2 Chemical Properties
Pale Yellow Solid
2.3 Color/Form
white to beige
2.4 pKa
2.5 StorageTemp
3. Use and Manufacturing
3.1 Definition
ChEBI: A 20-oxo steroid obtained by acetylation of the 17-hydroxy group of (11beta,17alpha)-17-acetyl-11-[4-(dimethylamino)phenyl]-3-oxoestra-4,9-dien-17-ol (ulipristal). A selective progesterone receptor modulator, which is emplyed as an emergency contraceptive.
3.2 GHS Classification
Signal: Danger
GHS Hazard Statements
Aggregated GHS information provided by 6 companies from 6 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

H302 (83.33%): Harmful if swallowed [Warning Acute toxicity, oral]
H312 (16.67%): Harmful in contact with skin [Warning Acute toxicity, dermal]
H319 (16.67%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]
H332 (16.67%): Harmful if inhaled [Warning Acute toxicity, inhalation]
H335 (16.67%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]
H360 (33.33%): May damage fertility or the unborn child [Danger Reproductive toxicity]
H361 (50%): Suspected of damaging fertility or the unborn child [Warning Reproductive toxicity]
H362 (16.67%): May cause harm to breast-fed children [Reproductive toxicity, effects on or via lactation]
H413 (33.33%): May cause long lasting harmful effects to aquatic life [Hazardous to the aquatic environment, long-term hazard]

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown.

Precautionary Statement Codes
P201, P202, P260, P261, P263, P264, P270, P271, P273, P280, P281, P301+P312, P302+P352, P304+P312, P304+P340, P305+P351+P338, P308+P313, P312, P322, P330, P337+P313, P363, P403+P233, P405, and P501
4. Safety and Handling
4.1 Symbol
4.1 Signal Word
4.1 Hazard Declaration
NONH for all modes of transport
4.1 Caution Statement
4.1 Specification

 19-Norpregna-4,9-diene-3,20-dione,17-(acetyloxy)-11-[4-(dimethylamino)phenyl]-, (11b)- , its cas register number 126784-99-4. It also can be called Ulipristal ; CBD 2914 ; VA 2914 ; (11b)-17-(Acetyloxy)-11-[4-(dimethylamino)phenyl]-19-norpregna-4,9-diene-3,20-dione ; 17-Acetoxy-11-(4-N,N-dimethylaminophenyl)pregna-4,9-diene-3,20-dione ; and Ellaone .


2.Hazard identification

2.1 Classification of the substance or mixture

no data available

2.2 GHS label elements, including precautionary statements

Pictogram(s) no data available
Signal word

no data available

Hazard statement(s)

no data available

Precautionary statement(s)

no data available


no data available


no data available


no data available

2.3 Other hazards which do not result in classification

no data available

9. Other Information
9.0 Pharmacological action
Ulinastal acetate is a progesterone agonist/antagonist that inhibits or delays the ovulation; however, changes in the endometrium may also be a cause of efficacy.
Ulinastal acetate belongs to the category of selective progesterone receptor modulator, and it has partial agonistic action to progesterone receptor antagonism and partial agonism. It binds to progesterone receptors in the human body and prevents progesterone receptor binding. The efficacy of Ulinastal acetate depends on the time of administration in the menstrual cycle. Administration during the mid-follicular hyperplasia would suppress follicle formation and decrease the estradiol concentrations. And the administration during the in the peak period of follicular hyperplasia can delay the breakdown of follicles from 5 to 9 days. Although early luteal phase of administration cannot significantly delay the endometrial maturation, it can reduce the thickness of the endometrium within 0.6±2.2mm(average value ±SD).
9.1 Description
Ulipristal acetate is a synthetic steroid derived from 19-nor-progesterone that exerts potent progesterone receptor (PR) antagonist activity at the transcriptional level. It is an orally administered drug indicated for emergency contraception (i.e., postcoital contraception) up to 120 h following unprotected intercourse. Ulipristal acetate is the second oral progestogen marketed for this indication behind levonorgestrel. As PR antagonists, both drugs are believed to act via delay of ovulation and inhibition of follicular development. Levonorgestrel 1.5 mg is approved for contraception up to 72 h following unprotected intercourse and is widely accessible via prescription, and directly from clinics and community pharmacies. Prior to ulipristal acetate, the only approved postcoital contraceptive option between 72 and 120 h was the insertion of an intrauterine device (IUD). The recommended dose of ulipristal acetate is one 30-mg tablet taken as soon as possible and no more than 120 h following intercourse. The vast majority of PR antagonists belonging to the mifepristone (RU486) family also bind to the glucocorticoid receptor (GR) with high affinity and thereby exert antiglucocorticoid activity.
The most common adverse effects with ulipristal acetate were headache, dysmenorrhea, nausea, abdominal pain, dizziness, fatigue, and upper abdominal pain.
9.2 Originator
Research Triangle Institute (US)
9.3 Brand name
9.4 Biochem/physiol Actions
Ulipristal acetate is a selective progesterone receptor modulator (SPRM) with tissue-selective partial antagonist activity. It has clinical use both as an emergency contraceptive and as a treatment for uterine fibroids. Ulipristal acetate acts as a partial antagonist on the hypothalamic–pituitary–ovarian axis to inhibit or delay ovulation without affecting human embryo implantation. As a progesterone antagonist, Ulipristal acetate selectively suppresses neo-vascularization, cell proliferation, and survival in uterine fibroid cells, but not in normal myometrial cells.
9.5 Clinical Use
Ulipristal acetate, a selective progesterone receptor modulator (SPRM), was developed at the Research Triangle Institute. In 2009, HRA Pharma received FDA approval for emergency contraception within 120 h (5 days) of unprotected sexual intercourse or contraceptive failure. Ulipristal acetate is a well-known steroid that possesses antiprogestational and antiglucocorticoid activity. It is the first SPRM that was specifically designed as an oral emergency contraceptive. Unlike earlier levonorgestrel-based emergency contraceptives, this SPRM drug maintains efficacy for 5 days after unprotected intercourse while having safety profile comparable to levonorgestrel.
9.6 Chemical Synthesis
Recently, an industrial scale route was published and is described in the scheme.89 Alkylation of commercially available 3-(ethylenedioxy)-19-estra-5(10),9(11)- diene-17-one (129, multiple vendors) with tBuOK and acetylene in THF at 0°C gave alcohol 130 in 95% yield, which was subsequently treated with phenylsulfenyl chloride in the presence of TEA and AcOH in DCM/CHCl3 at 5°C to 0°C to effect thiolester formation followed by sulphinate-sulphoxide rearrangement to give allene sulphoxide 131 in 88% yield. Compound 131 was treated with NaOMe/MeOH at 64°C to give the corresponding enol ether and then the enol ether was treated with trimethyl phosphite at the same temperature for sulphoxide-sulphinate rearrangement to furnish hydroxyl enol ether 132 in 67% yield. Compound 132 was demethylated with 1 M HCl in methanol to give the corresponding ketone 133 in 95% yield which was protected using ethylene glycol, pTsOH and trimethyl orthophosphate in DCM to afford cyclopentyl ketal 134 in 87% yield. Epoxidation of 134 in the presence of hexachloroacetone and H2O2 in pyridine and DCM at 0°C provided a 55:45 mixture of the 5-a,10-a epoxides (135, 136). The crude epoxides 135 and 136 were reacted with 4-( N,N-dimethylamino)-phenyl magnesium bromide in THF in the presence of CuCl in DCM to furnish the mixture of diastereomers 137 and 138 in 46% yield over two steps. The mixture (137 and 138) was then treated with KHSO4 in water at 5°C to affect dehydration and liberation of the keto functional group to give 139 which was used in the next step without isolation. Compound 139 was acetylated with acetic anhydride and perchloric acid in DCM at 30°C to afford the ulipristal acetate (XXI) in 66% yield over the final two steps.

9.7 Oral emergency contraception
Ulinastal acetate is a new oral contraceptive pill, and it is the active chemical composition of Ella, a new generation of emergency contraceptive wildly on the market in United States currently. It can protect women within 120 hours after intercourse without medication, and the emergency contraceptive efficacy will not decline with the delay of treatment time. At the same time, it is safe and durable. Compared with the most commonly used emergency contraceptive levonorgestrel, Ulinastal acetate is more suitable for clinical use, and has the potential to prevent more unwanted pregnancies.
Ulipristal acetate was developed by HRA Pharmaceuticals, Inc., and was marketed by the Food and Drug Administration (FDA) in August 2010 under the trade name Ella. It could be used for the protection of unprotected sex or for the pregnancy prevention in the known or suspected contraceptive failure situation within 120h. Ulipristal acetate is a selective progesterone receptor modulator; and mainly it can take effect by inhibiting the ovulation and plays an emergency contraceptive effect. The study found that Ulastatal acetate was more effective than levonorgestrel in suppressing vomiting after dosing before the estimated ovulation day. And it consequently suggests that Ulatastatin acetate might have a stronger emergency contraceptive effectiveness.
the structure of ulcaritin acetate
Figure 1 for the structure of ulcaritin acetate
9.8 market prospect
Emergency contraception, also known as after-birth control pills, is a kind of contraceptive for women of childbearing age in the situation od non-protective intercourse or contraceptive failure after the use of contraception to prevent accidental pregnancy.
At present, the most widely used emergency contraceptive is levonorgestrel (1evonorgestre1), which is used at intervals of 12hours each serving one piece (0.75mg) or a single taking of two pieces(1.5mg). However, levonorgestrel was only approved for using as an emergency contraceptive only 72 hours (3days) after unprotected intercourse or contraceptive failure. Even though, the efficacy of levonorgestrel emergency contraception will be significantly reduced with the delay of treatment time; it is recommended that it should better used in unprotected intercourse or contraceptive failure within 12h after the start of medication.
In May 2009, the European Union approved a new emergency contraceptive ulipristal acetate, also called as Ella One, which is not only allowed to be taken within 120 hours (5 days) of unprotected intercourse or contraceptive failure, but the  emergency contraceptive efficacy would not delay and decline with the medication time.
Ulastat is one of the first oral contraceptives approved worldwide to be administered within 120 hours of unprotected intercourse or contraceptive failure, which has the potential to prevent more unwanted pregnancies than levonorgestrel. As a new oral emergency contraceptive, Ulinastal acetate can not only be used within 120 hours after unprotected intercourse, but the efficacy of emergency contraception would not decrease with the delay of administration, and it is safe and durable as well. Compared with the most commonly used emergency contraceptive levonorgestrel, Ulinastal acetate is more suitable for clinical use, and it has the potential to prevent more unwanted pregnancies.
9.9 intellectual property rights
The original research manufacturer in China has already applied for a patent for Ulinastal acetate tablets and its indications as well as for its indications. However, it has not been authorized yet. There are not any intellectual property barriers.
9.10 Other clinical researches
February 2, 2012, The New England Journal of Medicine published two clinical trials found that Ulinastal acetate has an excellent effect in the treatment of uterine fibroids. The results show that Ulinastal acetate is as effective as leuprolide in controlling uterine fibroid bleeding, reducing the volume of myoma and comforting the pain;
According to statistics, about a quarter of women have suffered from uterine fibroids symptoms. Leuprolide acetate, a gonadotropin-releasing hormone (GnRH) agonist, has been approved for preoperative treatment of uterine fibroids since its approval in 1995. Ulinastal acetate can successfully challenge leuprolide and it becomes become a new choice for preoperative uterine fibroids drug therapy. Let’s wait for the post-trial to reveal the answer.
9.11 References
[1] Shilpa P. Jadav, Dinesh M. Parmar (2012) Ulipristal acetate, a progesterone receptor modulator for emergency contraception, J Pharmacol Pharmacother, 3, 109-111
[2] Ulipristal acetate for fibroids,
[3] Elena Rosato, Manuela Farris, Carbo Bastianeli (2015) Mechanism of Action of Ulipristal Acetate for Emergency Contraception: A Systematic Review, Front Pharmacol, 6, 315
9.12 Chemical Properties
Pale Yellow Solid
9.13 Uses
Ulipristal acetate is a selective progesterone receptor modulator
9.14 Uses
Labelled Ulipristal
9.15 Definition
ChEBI: A 20-oxo steroid obtained by acetylation of the 17-hydroxy group of (11beta,17alpha)-17-acetyl-11-[4-(dimethylamino)phenyl]-3-oxoestra-4,9-dien-17-ol (ulipristal). A selective progesterone receptor modulator, which is empl yed as an emergency contraceptive.
9.16 Mesh
Contraceptive agents that act on the ENDOCRINE SYSTEM. (See all compounds classified as Contraceptive Agents, Hormonal.)|Chemical substances or agents with contraceptive activity in females. Use for female contraceptive agents in general or for which there is no specific heading. (See all compounds classified as Contraceptive Agents, Female.)
9.17 Mesh Entry Terms
9.18 Use Classification
Human drugs -> Esmya -> EMA Drug Category|Sex hormones and modulators of the genital system -> Human pharmacotherapeutic group|Human drugs -> Ulipristal Acetate Gedeon Richter -> EMA Drug Category|Human drugs -> ellaOne -> EMA Drug Category|Sex hormones and modulators of the genital system, Emergency contraceptives -> Human pharmacotherapeutic group|Human Drugs -> EU pediatric investigation plans|Human Drugs -> FDA Approved Drug Products with Therapeutic Equivalence Evaluations (Orange Book) -> Active Ingredients
10. Computational chemical data
  • Molecular Weight: 475.629g/mol
  • Molecular Formula: C30H37NO4
  • Compound Is Canonicalized: True
  • XLogP3-AA: 3.5
  • Exact Mass: 475.27225866
  • Monoisotopic Mass: 475.27225866
  • Complexity: 984
  • Rotatable Bond Count: 5
  • Hydrogen Bond Donor Count: 0
  • Hydrogen Bond Acceptor Count: 5
  • Topological Polar Surface Area: 63.7
  • Heavy Atom Count: 35
  • Defined Atom Stereocenter Count: 5
  • Undefined Atom Stereocenter Count: 0
  • Defined Bond Stereocenter Count: 0
  • Undefined Bond Stereocenter Count: 0
  • Isotope Atom Count: 0
  • Covalently-Bonded Unit Count: 1
11. Question & Answer
  • Ulipristal acetate is a selective progesterone receptor modulator.5 It is a partial agonist, exerting agonist and antagonist activity at the progesterone receptor. While it has been used in the medical management of uterine fibroids,6 it is more commonly used for emergency contraception. Ulipristal...
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