17β-Dihydroequilenin

Chemical compound

17β-Dihydroequilenin
Clinical data

Other names	β-Dihydroequilenin; Δ^6,8-17β-Estradiol; 6,8-Didehydro-17β-estradiol; Estra-1,3,5(10),6,8-pentaen-3,17β-diol
Routes of administration	By mouth
Drug class	Estrogen
Identifiers
IUPAC name (13S,14S,17S)-13-methyl-11,12,14,15,16,17-hexahydrocyclopenta[a]phenanthrene-3,17-diol
CAS Number	1423-97-8
PubChem CID	3032407
ChemSpider	2297390
ChEMBL	ChEMBL123405
CompTox Dashboard (EPA)	DTXSID40931405
Chemical and physical data
Formula	C₁₈H₂₀O₂
Molar mass	268.356 g·mol⁻¹
3D model (JSmol)	Interactive image
SMILES C[C@]12CCC3=C([C@@H]1CC[C@@H]2O)C=CC4=C3C=CC(=C4)O
InChI InChI=1S/C18H20O2/c1-18-9-8-14-13-5-3-12(19)10-11(13)2-4-15(14)16(18)6-7-17(18)20/h2-5,10,16-17,19-20H,6-9H2,1H3/t16-,17-,18-/m0/s1 Key:RYWZPRVUQHMJFF-BZSNNMDCSA-N

17β-Dihydroequilenin, or β-dihydroequilenin, also known as δ^6,8-17β-estradiol or 6,8-didehydro-17β-estradiol, as well as estra-1,3,5(10),6,8-pentaen-3,17β-diol, is a naturally occurring steroidal estrogen found in horses which is closely related to equilin, equilenin, and estradiol, and, as the 3-sulfate ester sodium salt, is a minor constituent (0.5%) of conjugated estrogens (Premarin).^[1] 17β-Dihydroequilenin has unexpectedly shown a selective estrogen receptor modulator (SERM)-like profile of estrogenic activity in studies with monkeys, in which beneficial effects on bone and the cardiovascular system were noted but proliferative responses in breast and endometrium were not observed.^[2]

References

^ Fritz MA, Speroff L (28 March 2012). "Postmenopausal Hormone Therapy". Clinical Gynecologic Endocrinology and Infertility. Lippincott Williams & Wilkins. pp. 751–. ISBN 978-1-4511-4847-3.
^ Cline JM (April 2007). "Assessing the mammary gland of nonhuman primates: effects of endogenous hormones and exogenous hormonal agents and growth factors". Birth Defects Research. Part B, Developmental and Reproductive Toxicology. 80 (2): 126–146. doi:10.1002/bdrb.20112. PMID 17443713.

Estrogens and antiestrogens

Estrogens

ERTooltip Estrogen receptor agonists	Steroidal: Alfatradiol Certain androgens/anabolic steroids (e.g., testosterone, testosterone esters, methyltestosterone, metandienone, nandrolone esters) (via estrogenic metabolites) Certain progestins (e.g., norethisterone, noretynodrel, etynodiol diacetate, tibolone) Clomestrone Cloxestradiol acetate Conjugated estriol Conjugated estrogens Epiestriol Epimestrol Esterified estrogens Estetrol^† Estradiol Estradiol esters (e.g., estradiol acetate, estradiol benzoate, estradiol cypionate, estradiol enanthate, estradiol undecylate, estradiol valerate, polyestradiol phosphate, estradiol ester mixtures (Climacteron)) Estramustine phosphate Estriol Estriol esters (e.g., estriol succinate, polyestriol phosphate) Estrogenic substances Estrone Estrone esters Estrone sulfate Estropipate (piperazine estrone sulfate) Ethinylestradiol^# Ethinylestradiol sulfonate Hydroxyestrone diacetate Mestranol Methylestradiol Moxestrol Nilestriol Prasterone (dehydroepiandrosterone; DHEA) Prasterone enanthate Prasterone sulfate Promestriene Quinestradol Quinestrol Nonsteroidal: Benzestrol Bifluranol Chlorotrianisene Dienestrol Dienestrol diacetate Diethylstilbestrol (stilbestrol) Diethylstilbestrol esters/ethers Dimestrol (diethylstilbestrol dimethyl ether) Fosfestrol (diethylstilbestrol diphosphate) Mestilbol (diethylstilbestrol monomethyl ether) Doisynoestrol (fenocycline) Hexestrol Hexestrol esters Methallenestril Methestrol (promethestrol) Methestrol dipropionate (promethestrol dipropionate) Paroxypropione Quadrosilan Triphenylbromoethylene Triphenylchloroethylene Zeranol
Progonadotropins	Antiandrogens (e.g., bicalutamide) GnRH agonists (e.g., GnRH (gonadorelin), leuprorelin) Gonadotropins (e.g., FSHTooltip follicle-stimulating hormone, LHTooltip luteinizing hormone)

ERTooltip Estrogen receptor agonists

Steroidal: Alfatradiol
Certain androgens/anabolic steroids (e.g., testosterone, testosterone esters, methyltestosterone, metandienone, nandrolone esters) (via estrogenic metabolites)
Certain progestins (e.g., norethisterone, noretynodrel, etynodiol diacetate, tibolone)
Clomestrone
Cloxestradiol acetate
Conjugated estriol
Conjugated estrogens
Epiestriol
Epimestrol
Esterified estrogens
Estetrol^†
Estradiol
Estradiol esters (e.g., estradiol acetate, estradiol benzoate, estradiol cypionate, estradiol enanthate, estradiol undecylate, estradiol valerate, polyestradiol phosphate, estradiol ester mixtures (Climacteron))
Estramustine phosphate
Estriol
Estriol esters (e.g., estriol succinate, polyestriol phosphate)
Estrogenic substances
Estrone
Estrone esters
- Estrone sulfate
- Estropipate (piperazine estrone sulfate)
Ethinylestradiol^#
- Ethinylestradiol sulfonate
Hydroxyestrone diacetate
Mestranol
Methylestradiol
Moxestrol
Nilestriol
Prasterone (dehydroepiandrosterone; DHEA)
- Prasterone enanthate
- Prasterone sulfate
Promestriene
Quinestradol
Quinestrol

Progonadotropins

Antiandrogens (e.g., bicalutamide)
GnRH agonists (e.g., GnRH (gonadorelin), leuprorelin)
Gonadotropins (e.g., FSHTooltip follicle-stimulating hormone, LHTooltip luteinizing hormone)

Antiestrogens

ERTooltip Estrogen receptor antagonists (incl. SERMsTooltip selective estrogen receptor modulators/SERDsTooltip selective estrogen receptor downregulators)	Acolbifene^† Anordrin Bazedoxifene Broparestrol Clomifene^# Cyclofenil Enclomifene^† Epitiostanol Lasofoxifene Mepitiostane Ormeloxifene Ospemifene Raloxifene Tamoxifen^# Toremifene Exclusively antagonistic: Elacestrant Fulvestrant Noncompetitive inhibitors: Trilostane
Aromatase inhibitors	First-generation: Aminoglutethimide Testolactone Second-generation: Fadrozole Formestane Third-generation: Anastrozole Exemestane Letrozole
Antigonadotropins	Androgens/anabolic steroids (e.g., testosterone, testosterone esters, nandrolone esters, oxandrolone, fluoxymesterone) D₂ receptor antagonists (prolactin releasers) (e.g., domperidone, metoclopramide, risperidone, haloperidol, chlorpromazine, sulpiride) GnRH agonists (e.g., leuprorelin, goserelin) GnRH antagonists (e.g., cetrorelix, elagolix) Progestogens (e.g., chlormadinone acetate, cyproterone acetate, gestonorone caproate, hydroxyprogesterone caproate, medroxyprogesterone acetate, megestrol acetate)
Others	Mixed mechanism of action: Danazol Gestrinone Androstenedione immunogens: Androvax (androstenedione albumin) Ovandrotone albumin (Fecundin)

^#WHO-EM
^‡Withdrawn from market
Clinical trials:
- ^†Phase III
- ^§Never to phase III

See also: Estrogen receptor modulators; Androgens and antiandrogens; Progestogens and antiprogestogens; List of estrogens

Estrogen receptor modulators

ERTooltip Estrogen receptor

Agonists	Steroidal: 2-Hydroxyestradiol 2-Hydroxyestrone 3-Methyl-19-methyleneandrosta-3,5-dien-17β-ol 3α-Androstanediol 3α,5α-Dihydrolevonorgestrel 3β,5α-Dihydrolevonorgestrel 3α-Hydroxytibolone 3β-Hydroxytibolone 3β-Androstanediol 4-Androstenediol 4-Androstenedione 4-Fluoroestradiol 4-Hydroxyestradiol 4-Hydroxyestrone 4-Methoxyestradiol 4-Methoxyestrone 5-Androstenediol 7-Oxo-DHEA 7α-Hydroxy-DHEA 7α-Methylestradiol 7β-Hydroxyepiandrosterone 8,9-Dehydroestradiol 8,9-Dehydroestrone 8β-VE2 10β,17β-Dihydroxyestra-1,4-dien-3-one (DHED) 11β-Chloromethylestradiol 11β-Methoxyestradiol 15α-Hydroxyestradiol 16-Ketoestradiol 16-Ketoestrone 16α-Fluoroestradiol 16α-Hydroxy-DHEA 16α-Hydroxyestrone 16α-Iodoestradiol 16α-LE2 16β-Hydroxyestrone 16β,17α-Epiestriol (16β-hydroxy-17α-estradiol) 17α-Estradiol (alfatradiol) 17α-Dihydroequilenin 17α-Dihydroequilin 17α-Epiestriol (16α-hydroxy-17α-estradiol) 17α-Ethynyl-3α-androstanediol 17α-Ethynyl-3β-androstanediol 17β-Dihydroequilenin 17β-Dihydroequilin 17β-Methyl-17α-dihydroequilenin Abiraterone Abiraterone acetate Alestramustine Almestrone Anabolic steroids (e.g., testosterone and esters, methyltestosterone, metandienone (methandrostenolone), nandrolone and esters, many others; via estrogenic metabolites) Atrimustine Bolandiol Bolandiol dipropionate Butolame Clomestrone Cloxestradiol Cloxestradiol acetate Conjugated estriol Conjugated estrogens Cyclodiol Cyclotriol DHEA DHEA-S ent-Estradiol Epiestriol (16β-epiestriol, 16β-hydroxy-17β-estradiol) Epimestrol Equilenin Equilin ERA-63 (ORG-37663) Esterified estrogens Estetrol Estradiol Estradiol esters Lipoidal estradiol Polyestradiol phosphate Estramustine Estramustine phosphate Estrapronicate Estrazinol Estriol Estriol esters Polyestriol phosphate Estrofurate Estrogenic substances Estromustine Estrone Estrone esters Estrone methyl ether Estropipate Etamestrol (eptamestrol) Ethinylandrostenediol Ethandrostate Ethinylestradiol Ethinylestradiol 3-benzoate Ethinylestradiol sulfonate Ethinylestriol Ethylestradiol Etynodiol Etynodiol diacetate Hexolame Hippulin Hydroxyestrone diacetate Lynestrenol Lynestrenol phenylpropionate Mestranol Methylestradiol Moxestrol Mytatrienediol Nilestriol Norethisterone Noretynodrel Orestrate Pentolame Prodiame Prolame Promestriene RU-16117 Quinestradol Quinestrol Tibolone Nonsteroidal: (R,R)-THC (S,S)-THC 2,8-DHHHC β-LGND1 β-LGND2 (GTx-878) AC-186 Allenestrol Allenolic acid Benzestrol Bifluranol Bisdehydrodoisynolic acid Butestrol Carbestrol D-15414 DCW234 Diarylpropionitrile Dienestrol Dienestrol diacetate Diethylstilbestrol Diethylstilbestrol esters Dimestrol (dianisylhexene) Dimethylstilbestrol Doisynoestrol (fenocycline) Doisynolic acid Efavirenz Elacestrant ERB-196 (WAY-202196) Erteberel (SERBA-1, LY-500307) Estrobin (DBE) Fenestrel FERb 033 Fosfestrol (diethylstilbestrol diphosphate) Furostilbestrol (diethylstilbestrol difuroate) GTx-758 Hexestrol Hexestrol esters ICI-85966 (Stilbostat) M2613 meso-Butestrol meso-Hexestrol Mestilbol Methallenestril Methestrol Methestrol dipropionate Paroxypropione Pentafluranol Phenestrol Prinaberel (ERB-041, WAY-202041) Propylpyrazoletriol Quadrosilan SC-3296 SC-4289 SERBA-2 SKF-82,958 Terfluranol Triphenylbromoethylene Triphenylchloroethylene Triphenyliodoethylene Triphenylmethylethylene (triphenylpropene) WAY-166818 WAY-169916 WAY-200070 WAY-204688 (SIM-688) WAY-214156 Unknown/unsorted: ERB-26 ERA-45 ERB-79 ZK-283197 Xenoestrogens: Anise-related (e.g., anethole, anol, dianethole, dianol, photoanethole) Chalconoids (e.g., isoliquiritigenin, phloretin, phlorizin (phloridzin), wedelolactone) Coumestans (e.g., coumestrol, psoralidin) Flavonoids (incl. 7,8-DHF, 8-prenylnaringenin, apigenin, baicalein, baicalin, biochanin A, calycosin, catechin, daidzein, daidzin, ECG, EGCG, epicatechin, equol, formononetin, glabrene, glabridin, genistein, genistin, glycitein, kaempferol, liquiritigenin, mirificin, myricetin, naringenin, penduletin, pinocembrin, prunetin, puerarin, quercetin, tectoridin, tectorigenin) Lavender oil Lignans (e.g., enterodiol, enterolactone, nyasol (cis-hinokiresinol)) Metalloestrogens (e.g., cadmium) Pesticides (e.g., alternariol, dieldrin, endosulfan, fenarimol, HPTE, methiocarb, methoxychlor, triclocarban, triclosan) Phytosteroids (e.g., digitoxin (digitalis), diosgenin, guggulsterone) Phytosterols (e.g., β-sitosterol, campesterol, stigmasterol) Resorcylic acid lactones (e.g., zearalanone, α-zearalenol, β-zearalenol, zearalenone, zeranol (α-zearalanol), taleranol (teranol, β-zearalanol)) Steroid-like (e.g., deoxymiroestrol, miroestrol) Stilbenoids (e.g., resveratrol, rhaponticin) Synthetic xenoestrogens (e.g., alkylphenols, bisphenols (e.g., BPA, BPF, BPS), DDT, parabens, PBBs, PHBA, phthalates, PCBs) Others (e.g., agnuside, rotundifuran)
Mixed (SERMsTooltip Selective estrogen receptor modulators)	2-Phenylbenzofuran 2-Phenylbenzothiophene 4'-Hydroxynorendoxifen 27-Hydroxycholesterol Acefluranol Acolbifene Afimoxifene Anordiol Anordrin Arzoxifene Bazedoxifene Brilanestrant Broparestrol Camizestrant Chlorotrianisene Clomifene Clomifenoxide CN-55945-27 Cyclofenil D-15413 Desmethylchlorotrianisene Droloxifene Enclomifene Endoxifen Etacstil (GW-5638, DPC-974) Ethamoxytriphetol (MER-25) Femarelle Fispemifene GW-7604 ICI-55548 Idoxifene Lasofoxifene Levormeloxifene LN-1643 LN-2299 LY-117018 Menerba Miproxifene Miproxifene phosphate MRL-37 Nafoxidine Nitromifene NNC 45-0095 NNC 45-0320 NNC 45-0781 NNC 45-1506 Ormeloxifene Ospemifene Panomifene Pipendoxifene Promensil Raloxifene Rimostil (P-081) Spironolactone SS1010 Tamoxifen TAS-108 (SR-16234) Toremifene Trioxifene TZE-5323 U-11555A U-11634 Y-134 Zindoxifene Zuclomifene
Antagonists	(R,R)-THC 7β-Hydroxy-DHEA Chloroindazole Cytestrol acetate EM-800 (SCH-57050) Epitiostanol ERA-90 ERB-88 Fulvestrant (ICI-182780) Glyceollins (I, II, III, IV) ICI-164384 MDL-101906 Mepitiostane Methylepitiostanol Methylpiperidinopyrazole MIBE Oxabicycloheptene sulfonate Phenytoin PHTPP Prochloraz RU-39411 RU-58668 SS1020 TAS-108 (SR-16234) ZB716 ZK-164015 ZK-191703 Coregulator-binding modulators: ERX-11 Noncompetitive inhibitors: Trilostane

GPERTooltip G protein-coupled estrogen receptor

Agonists	2-Methoxyestradiol 7β-Hydroxyepiandrosterone Afimoxifene (4-hydroxytamoxifen) Aldosterone Atrazine Bisphenol A Daidzein DDT (p,p'-DDT, o',p'-DDE) Diarylpropionitrile Equol Estradiol Ethinylestradiol Fulvestrant (ICI-182780) G-1 Genistein GPER-L1 GPER-L2 Hydroxytyrosol Kepone Niacin Niacinamide Nonylphenol Oleuropein PCBs (2,2',5'-PCB-4-OH) Propylpyrazoletriol Quercetin Raloxifene Resveratrol STX Tamoxifen Tectoridin
Antagonists	CCL18 Estriol G-15 G-36 MIBE
Unknown	Diethylstilbestrol Zearalenone

See also: Receptor/signaling modulators; Estrogens and antiestrogens; Androgen receptor modulators; Progesterone receptor modulators; List of estrogens