Equilenin

Equilenin

Clinical data
Other names	6,8-Didehydroestrone; Estra-1,3,5(10),6,8-pentaen-3-ol-17-one
Routes of administration	By mouth
Drug class	Estrogen
Identifiers
IUPAC name (13S,14S)-3-hydroxy-13-methyl-12,14,15,16-tetrahydro-11H-cyclopenta[a]phenanthren-17-one
CAS Number	517-09-9^Y
PubChem CID	444865
DrugBank	DB03515^Y
ChemSpider	392668^Y
UNII	W8FTJ17C4J
KEGG	C14303^Y
ChEBI	CHEBI:34739
ChEMBL	ChEMBL225546^Y
CompTox Dashboard (EPA)	DTXSID2052156
ECHA InfoCard	100.007.483
Chemical and physical data
Formula	C18H18O2
Molar mass	266.340 g·mol^−1
3D model (JSmol)	Interactive image
SMILES O=C4[C@]3(CCc1c(ccc2c1ccc(O)c2)[C@@H]3CC4)C
InChI InChI=1S/C18H18O2/c1-18-9-8-14-13-5-3-12(19)10-11(13)2-4-15(14)16(18)6-7-17(18)20/h2-5,10,16,19H,6-9H2,1H3/t16-,18-/m0/s1^Y Key:PDRGHUMCVRDZLQ-WMZOPIPTSA-N^Y
^NY (what is this?)  (verify)

Equilenin, also known as 6,8-didehydroestrone, as well as estra-1,3,5(10),6,8-pentaen-3-ol-17-one, is a naturally occurring steroidal estrogen obtained from the urine of pregnant mares.^[1][2] It is used as one of the components in conjugated estrogens (brand name Premarin).^[2] It was the first complex natural product to be fully synthesized, in work reported by 1940 by Bachmann and Wilds.^[3]

Chemistry

Synthesis

Total synthesis

The synthesis developed by the Bachmann group started from Butenand's ketone^[4] – the 7-methoxy structural analog of 1,2,3,4-tetrahydrophenanthren-1-one^[5] – and which can be readily prepared from 1,6-Cleve's acid.^[6] The approach was based on well-established transformations like the Claisen condensation, the Reformatsky reaction, the Arndt–Eistert reaction, and the Dieckmann condensation.^[3] Nicolaou described this preparation as ending the era preceding the post-World War II work of Robert Burns Woodward that introduced enantioselective synthesis;^[4] in this synthesis, a mixture of stereoisomers were prepared and then resolved,^[6] and the choice of target was partly because of the existence of only two chiral carbons and hence only four stereoisomers.^[5]

The overall yield of the synthesis was 2.7% based on a twenty-step process starting from Cleve's acid.^[6]

See also

• List of estrogens § Equine estrogens

References

1. Elks J (14 November 2014). The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies. Springer. pp. 494–. ISBN 978-1-4757-2085-3.
2. Fritz MA, Speroff L (28 March 2012). Clinical Gynecologic Endocrinology and Infertility. Lippincott Williams & Wilkins. pp. 751–. ISBN 978-1-4511-4847-3.
3. Bachmann WE, Cole W, Wilds AL (1940). "The Total Synthesis of the Sex Hormone Equilenin and Its Stereoisomers". J. Am. Chem. Soc. 62 (4): 824–839. doi:10.1021/ja01861a036.
4. Nicolaou KC, Vourloumis D, Winssinger N, Baran PS (January 2000). "The Art and Science of Total Synthesis at the Dawn of the Twenty-First Century" (PDF). Angewandte Chemie. 39 (1): 44–122. doi:10.1002/(SICI)1521-3773(20000103)39:1<44::AID-ANIE44>3.0.CO;2-L. PMID 10649349. Archived from the original (PDF) on 2017-05-17. Retrieved 2017-07-22.
5. Bachmann WE, Cole W, Wilds AL (1939). "The Total Synthesis of the Sex Hormone Equilenin". J. Am. Chem. Soc. 61 (4): 974–975. doi:10.1021/ja01873a513.
6. Nakanishi K (1974). "Steroids". In Nakanishi K, Goto T, Itô S, Natori S, Nozoe S (eds.). Natural Products Chemistry. Vol. 1. Academic Press. pp. 421–545. ISBN 9781483218861.