Pregnenolone structure

In the early 1930 s, when the prime research aim was the commercial synthesis of the sex hormones (whose structures had just been elucidated), the principal raw material available was cholesterol extracted from the spinal cord or brain of cattle or from sheep wool grease. This sterol (as its 3-acetate 5,6-dibromide) was subjected to a rather drastic chromic acid oxidation, which produced a variety of acidic, ketonic and hydroxylated products derived mainly by attack on the alkyl side-chain. The principal ketonic material, 3j -hydroxyandrost-5-en-17-one, was obtained in yields of only about 7% another useful ketone, 3 -hydroxypregn-5-en-20-one (pregnenolone) was obtained in much lower yield. The chief acidic product was 3j -hydroxy-androst-5-ene-17j -carboxylic acid. All three of these materials were then further converted by various chemical transformations into steroid hormones and synthetic analogs ... 

Lee KA, Fuda H, Lee YC, Negishi M, Strott CA, Pedersen LC. Crystal structure of human cholesterol sulfotransferase (SULT2Blb) in the presence of pregnenolone and 3 -phosphoadenosine 5 -phosphate. Rationale for specificity differences between prototypical SULT2A1 and the SULT2BG1 isoforms. I Biol Chem 2003 278 44593-9. 

Structures of four derivatives of pregnenolone employed in GC/MS in (a) the 3-heptafluorobutyrate, in (b) the 3-trimethylsilyl ether 20-pentafluorobenzyloxime, in (c) the 3-trimethylsilyl ether 20-pentaf1uorobenzylcarbox-ymethoxime, and in (d) the 20-oxime... 

The anaesthetic steroid 3a-hydroxy-5a-pregnane-ll,20-dione has normal conformational features, both in the crystal and in solution. X-Ray data show that deoxycholic acid can form an inclusion complex in which alternate molecules of dimethyl sulphoxide and water are held in canals formed by helically arranged host molecules.Six different crystalline forms of 17a-ethynyloestradiol have been recognized. X-Ray structural data are reported for 3-methoxy-2-aza-oestra-l,3,5(10)-trien-17/3-yl acetate, 3/3-hydroxypregn-5-en-20-one (pregnenolone), 5a-cholest-2-ene, 3/3-bromo- and 3/3-chloro-cholest-5-enes, and cholesteryl acetate (at 123 K), benzoate, chloroformate, ° laurate, methyl carbonate, and 24-norcholesteryl acetate. ... 

The intermediates employed in the biosynthesis of androgens belong to two structurally different chemical classes, a,)3-unsaturated ketones (progesterone) and /3,y-unsatui ated alcohols (pregnenolone and dehydroepiandrosterone). The biosynthetic pathways in the production of androgens are also different [390]. 

Cytochrome P-450gf.p The demonstration of isozyme selectivity and the availability of structure-activity data has triggered efforts to construct irreversible inhibitors for biosynthetic cytochrome P-450 isozymes. Two types of mechanism-based inhibitors have been reported for cytochrome P-ASOg, the adrenal enzyme that oxidizes cholesterol to pregnenolone,1 3,104 cholesterol analogue ( ) with a triple bond between carbons 22 and 23 of the sidechain (the 20,22-bond is that which is normally cleaved) inactivates the enzyme by a catalysis-dependent mechanism.Replacement of carbon 24 and the attached sidechain carbons with a trimethylsilyl group (5 ) also results in inactivation of the enz3rme.l0 ... 

Infrared spectroscopy has been applied in identifying and determining the structures of steroids isolated from natural sources, for example, testis, ovary, placenta, adrenal cortex, bile, and blood. The technique has been used to identify compounds along the biosynthetic routes of, for example, cholesterol, pregnenolone, androgens, adrenal hormones, aldosterone, and estrogens. 

Lead.—The derivative Pb[C(CFs)2CN]2 is one of several [the analogous Hg, Ni, Co, Cr, and Cu compounds and Ag C(CF3)2 CN were also made] organometallic compounds obtained by treatment of the cyanide (CF3)2CH-CN with metal salts. Structure (22) has been assigned to a white solid that precipitates during the reaction of pregnenolone (23) with PbF2(OAc)2. The reactions of the solid are summarized in Scheme 16. ... 

Strushkevich N, MacKenzie F, Cherkesova T, Grab-ovec I, Usanov S, Park HW (2011) Structural basis for pregnenolone biosynthesis by the mitochondrial monooxygenase system. Proc Natl Acad Sci U S A 108 10139-10143... 

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