17α-Dihydroequilenin

17α-Dihydroequilenin, or α-dihydroequilenin, also known as 6,8-didehydro-17α-estradiol, as well as estra-1,3,5(10),6,8-pentaen-3,17α-diol, is a naturally occurring steroidal estrogen found in horses which is closely related to equilin, equilenin, and 17α-estradiol, and, as the 3-sulfate ester sodium salt, is a minor constituent (1.2%) of conjugated estrogens (Premarin).[1]

Composition of conjugated estrogens and properties of constituents

Compound	Synonym	Proportion (%)	Relative potency in the vagina (%)	Relative potency in the uterus (%)	RBA for ERα (%)	RBA for ERβ (%)	ERα / ERβ RBA ratio
Conjugated estrogens	–	100	38	100	–	–	–
Estrone	–	49.1–61.5	30	32	26	52	0.50
Equilin	Δ^7-Estrone	22.4–30.5	42	80	13	49	0.26
17α-Dihydroequilin	Δ^7-17α-Estradiol	13.5–19.5	0.06	2.6	41	32	1.30
17α-Estradiol	–	2.5–9.5	0.11	3.5	19	42	0.45
Δ^8-Estrone	–	3.5–3.9	?	?	19	32	0.60
Equilenin	Δ^6,8-Estrone	2.2–2.8	1.3	11.4	15	20–29	0.50–0.75
17β-Dihydroequilin	Δ^7-17β-Estradiol	0.5–4.0	83	200	113	108	1.05
17α-Dihydroequilenin	Δ^6,8-17α-Estradiol	1.2–1.6	0.018	1.3	20	49	0.40
17β-Estradiol	–	0.56–0.9	100	?	100	100	1.00
17β-Dihydroequilenin	Δ^6,8-17β-Estradiol	0.5–0.7	0.21	9.4	68	90	0.75
Δ^8-17β-Estradiol	–	Small amounts	?	?	68	72	0.94
Notes: All listed compounds are present in conjugated estrogen products specifically in the form of the sodium salts of the sulfate esters (i.e., as sodium estrone sulfate, sodium equilin sulfate, etc.). Sources: See template.

Not to be confused with 17α-Dihydroequilin, 17β-Dihydroequilin, or 17β-Dihydroequilenin.

17α-Dihydroequilenin

Clinical data
Other names	NSC-12171; α-Dihydroequilenin; 6,8-Didehydro-17α-estradiol; Estra-1,3,5(10),6,8-pentaen-3,17α-diol
Routes of administration	By mouth
Drug class	Estrogen
Identifiers
IUPAC name (13S,14S,17R)-13-methyl-11,12,14,15,16,17-hexahydrocyclopenta[a]phenanthrene-3,17-diol
CAS Number	6639-99-2
PubChem CID	223998
ChemSpider	194598
ChEBI	CHEBI:34178
ChEMBL	ChEMBL135236
ECHA InfoCard	100.026.955
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-KSZLIROESA-N

See also

• List of estrogens § Equine estrogens

References

1. Marc A. Fritz; Leon Speroff (28 March 2012). Clinical Gynecologic Endocrinology and Infertility. Lippincott Williams & Wilkins. pp. 751–. ISBN 978-1-4511-4847-3.