equilenin
{{Short description|Chemical compound}}
{{Drugbox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 461094560
| IUPAC_name = (13S,14S)-3-hydroxy-13-methyl-12,14,15,16-tetrahydro-11H-cyclopenta[a]phenanthren-17-one
| image = Equilenin.svg
| width = 225px
| tradename =
| pregnancy_category =
| legal_status =
| routes_of_administration = By mouth
| class = Estrogen
| bioavailability =
| protein_bound =
| metabolism =
| elimination_half-life =
| excretion =
| CAS_number_Ref = {{cascite|correct|??}}
| CAS_number = 517-09-9
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = W8FTJ17C4J
| ATC_prefix =
| ATC_suffix =
| ATC_supplemental =
| PubChem = 444865
| DrugBank_Ref = {{drugbankcite|correct|drugbank}}
| DrugBank = DB03515
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 392668
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = C14303
| ChEBI = 34739
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 225546
| synonyms = 6,8-Didehydroestrone; Estra-1,3,5(10),6,8-pentaen-3-ol-17-one
| C=18 | H=18 | O=2
| SMILES = O=C4[C@]3(CCc1c(ccc2c1ccc(O)c2)[C@@H]3CC4)C
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 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
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = PDRGHUMCVRDZLQ-WMZOPIPTSA-N
}}
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.{{cite book| vauthors = Elks J |title=The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies|url=https://books.google.com/books?id=0vXTBwAAQBAJ&pg=PA298|date=14 November 2014|publisher=Springer|isbn=978-1-4757-2085-3|pages=494–}}{{cite book| vauthors = Fritz MA, Speroff L |title=Clinical Gynecologic Endocrinology and Infertility|url=https://books.google.com/books?id=KZLubBxJEwEC&pg=PA751|date=28 March 2012|publisher=Lippincott Williams & Wilkins|isbn=978-1-4511-4847-3|pages=751–}} It is used as one of the components in conjugated estrogens (brand name Premarin). It was the first complex natural product to be fully synthesized, in work reported by 1940 by Bachmann and Wilds.{{cite journal|title = The Total Synthesis of the Sex Hormone Equilenin and Its Stereoisomers | vauthors = Bachmann WE, Cole W, Wilds AL |author-link1 = Werner Emmanuel Bachmann |author-link3 = Alfred L. Wilds |journal = J. Am. Chem. Soc. |year = 1940|volume = 62|issue = 4|pages = 824–839|doi = 10.1021/ja01861a036}}
Chemistry
=Synthesis=
==Total synthesis==
The synthesis developed by the Bachmann group started from Butenand's ketone – the 7-methoxy structural analog of 1,2,3,4-tetrahydrophenanthren-1-one{{cite journal|title = The Total Synthesis of the Sex Hormone Equilenin | vauthors = Bachmann WE, Cole W, Wilds AL |author-link1 = Werner Emmanuel Bachmann|author-link3 = Alfred L. Wilds|journal = J. Am. Chem. Soc.|year = 1939|volume = 61|issue = 4|pages = 974–975|doi = 10.1021/ja01873a513}} – and which can be readily prepared from 1,6-Cleve's acid.{{cite book | vauthors = Nakanishi K |chapter = Steroids | veditors = Nakanishi K, Goto T, Itô S, Natori S, Nozoe S |title = Natural Products Chemistry|volume = 1 |publisher = Academic Press|year = 1974|pages = 421–545 |isbn = 9781483218861|chapter-url = https://books.google.com/books?id=PKb-BAAAQBAJ&pg=PA491}} The approach was based on well-established transformations like the Claisen condensation, the Reformatsky reaction, the Arndt–Eistert reaction, and the Dieckmann condensation. Nicolaou described this preparation as ending the era preceding the post-World War II work of Robert Burns Woodward that introduced enantioselective synthesis;{{cite journal | vauthors = Nicolaou KC, Vourloumis D, Winssinger N, Baran PS | title = The Art and Science of Total Synthesis at the Dawn of the Twenty-First Century | journal = Angewandte Chemie | volume = 39 | issue = 1 | pages = 44–122 | date = January 2000 | pmid = 10649349 | doi = 10.1002/(SICI)1521-3773(20000103)39:1<44::AID-ANIE44>3.0.CO;2-L | url = http://yxzx.zjnu.edu.cn/lunwen/8.pdf | access-date = 2017-07-22 | url-status = dead | archive-url = https://web.archive.org/web/20170517074054/http://yxzx.zjnu.edu.cn/lunwen/8.pdf | archive-date = 2017-05-17 | authorlink1 = K. C. Nicolaou }} in this synthesis, a mixture of stereoisomers were prepared and then resolved, and the choice of target was partly because of the existence of only two chiral carbons and hence only four stereoisomers.
File:Bachmann's total synthesis of equilenin.jpg {{Clear}}
The overall yield of the synthesis was 2.7% based on a twenty-step process starting from Cleve's acid.
See also
References
{{Reflist}}
{{Estrogens and antiestrogens}}
{{Estrogen receptor modulators}}