Etynodiol

Etynodiol, or ethynodiol, is a steroidal progestin of the 19-nortestosterone group which was never marketed.^[1][2][3] A diacylated derivative, etynodiol diacetate, is used as a hormonal contraceptive.^[1][2] Etynodiol is sometimes used as a synonym for etynodiol diacetate.

Etynodiol

Clinical data
Other names	Ethynodiol; 3β-Hydroxynorethisterone; 17α-Ethynylestr-4-ene-3β,17β-diol
Drug class	Progestin; Progestogen
ATC code	G03DC06 (WHO)
Identifiers
IUPAC name (3S,8R,9S,10R,13S,14S,17R)-17-ethynyl-13-methyl-2,3,6,7,8,9,10,11,12,14,15,16-dodecahydro-1H-cyclopenta[a]phenanthrene-3,17-diol
CAS Number	1231-93-2
ChemSpider	14017
UNII	9E01C36A9S
CompTox Dashboard (EPA)	DTXSID1023025
ECHA InfoCard	100.013.610
Chemical and physical data
Formula	C20H28O2
Molar mass	300.442 g·mol−1
3D model (JSmol)	Interactive image
SMILES O[C@@H]4/C=C3\[C@@H]([C@H]2CC[C@]1([C@@H](CC[C@]1(C#C)O)[C@@H]2CC3)C)CC4
InChI InChI=1S/C20H28O2/c1-3-20(22)11-9-18-17-6-4-13-12-14(21)5-7-15(13)16(17)8-10-19(18,20)2/h1,12,14-18,21-22H,4-11H2,2H3/t14-,15-,16+,17+,18-,19-,20-/m0/s1 Key:JYILPERKVHXLNF-QMNUTNMBSA-N

It was patented in 1955.^[4]

Pharmacology

Etynodiol is a prodrug of norethisterone, and is converted immediately and completely into norethisterone.^[5][6][7] Etynodiol is an intermediate in the conversion of the prodrug lynestrenol into norethisterone.^[8]

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Relative affinities (%) of norethisterone, metabolites, and prodrugs

Compound	Typea	PRTooltip Progesterone receptor	ARTooltip Androgen receptor	ERTooltip Estrogen receptor	GRTooltip Glucocorticoid receptor	MRTooltip Mineralocorticoid receptor	SHBGTooltip Sex hormone-binding globulin	CBGTooltip Corticosteroid binding globulin
Norethisterone	–	67–75	15	0	0–1	0–3	16	0
5α-Dihydronorethisterone	Metabolite	25	27	0	0	?	?	?
3α,5α-Tetrahydronorethisterone	Metabolite	1	0	0–1	0	?	?	?
3α,5β-Tetrahydronorethisterone	Metabolite	?	0	0	?	?	?	?
3β,5α-Tetrahydronorethisterone	Metabolite	1	0	0–8	0	?	?	?
Ethinylestradiol	Metabolite	15–25	1–3	112	1–3	0	0.18	0
Norethisterone acetate	Prodrug	20	5	1	0	0	?	?
Norethisterone enanthate	Prodrug	?	?	?	?	?	?	?
Noretynodrel	Prodrug	6	0	2	0	0	0	0
Etynodiol	Prodrug	1	0	11–18	0	?	?	?
Etynodiol diacetate	Prodrug	1	0	0	0	0	?	?
Lynestrenol	Prodrug	1	1	3	0	0	?	?
Notes: Values are percentages (%). Reference ligands (100%) were promegestone for the PRTooltip progesterone receptor, metribolone for the ARTooltip androgen receptor, estradiol for the ERTooltip estrogen receptor, dexamethasone for the GRTooltip glucocorticoid receptor, aldosterone for the MRTooltip mineralocorticoid receptor, dihydrotestosterone for SHBGTooltip sex hormone-binding globulin, and cortisol for CBGTooltip Corticosteroid-binding globulin. Footnotes: a = Active or inactive metabolite, prodrug, or neither of norethisterone. Sources: See template.

Chemistry

See also: List of progestogens

Etynodiol is a 19-nortestosterone derivative. Structurally, it is almost identical to norethisterone and lynestrenol, differing only in its C3 substituent. Whereas norethisterone has a ketone at C3 and lynestrenol has no substituent at C3, etynodiol has a hydroxyl group at the position.

Synthesis

Ethynodiol diacetate synthesis:^[9] F. B. Colton, U.S. patent 2,843,609 (1958 to Searle). Prepn of the 3-acetate, 17-acetate, and diacetate: P. D. Klimstra, U.S. patent 3,176,013 (1965 to Searle); see also:^[10]

Society and culture

Generic names

Etynodiol is the generic name of the drug and its INNTooltip International Nonproprietary Name, while ethynodiol is its BANTooltip British Approved Name.^[1][2]