3704. α-Estradiol

Nomenclature

CAS number: 57-91-0
(17α)-Estra-1,3,5(10)-triene-3,17-diol; 1,3,5-estratriene-3,17α-diol; 3,17-dihydroxyestratriene.
C18H24O2; mol wt 272.38.
C 79.37%, H 8.88%, O 11.75%.

Description and references

Has been isolated from pregnancy urine of mares. Prepn from β-estradiol by inversion of the hydroxyl group at C-17 after tosylation: Allais, Hoffmann, US 2835681 (1958).

Chemical structure

Properties

Needles with 1/2 H2O from 80% alcohol, mp 220-223°. [α]D20 +53 to +56° (c = 0.9 in dioxane). Not precipitated by digitonin (in 80% alcoholic soln). Soluble in alcohol, acetone, aq alkalies. One gram dissolves in more than 100 ml of boiling benzene. Slightly sol in ether, chloroform. Insol in water, aq dil acids.

Derivative

Diacetate.
C22H28O4; mol wt 356.46.
C 74.13%, H 7.92%, O 17.95%.

Properties

mp 140-142°.

Derivative

3-Benzoate.
C25H28O3; mol wt 376.49.
C 79.75%, H 7.50%, O 12.75%.

Properties

mp 156-157°; also reported as polymorphous: I, mp 63°; II, mp 153°; III, mp 158°.