5P-Steroid

In fact, the production of 5p-steroids from A5-3p-ols, readily available and cheap starting materials, requires preliminar oxidation through the Oppenauer reaction or, more recently, fermentation to the A4-3-keto derivative5. From this one 5p steroids are readily obtained through catalytic hydrogenation4. 

TABLE 3.18 The Ratio of 5p K Kp to 5a Ketone from Hydrogenation of 3-Oxo-4-ene Steroids over Palladium Catalyst0  

Kitigenin (= (257 )-5(3-Spirostane-l(3,3(3,4p,5P-tetrol (steroidal saponin) Reineckia carnea (Liliaceae) [ bulb, root] cAMP PDE (179) 

TABLE 3.19 Rates of Hydrogenation and Selectivities for 5p-Ketone in Hydrogenation of 3-Oxo-4-ene and 19-Nor-3-oxo-4-ene Steroids over Palladium Catalyst in Pyridine and in Tetrahydrofuran/Hydrobromic Acid"6 

Another steric factor becomes important when working with bile acids or other A/B cis-(5p)-steroids 14. Despite the fact that the C9 —H bond is the most electronically favored for electrophilic substitution, ring A which is perpendicular to the steroidal plane blocks the access to it. The fluorine, which has to approach with a solvent molecule, attacks the other tertiary sites at C5, Cl 4 and C17.42 

Babcock and Fieser obtained 3P-methoxy steroids by hydrogenation of methyl 3-oxo-A-91-11 1 -cholenate (5), methyl dehydrolithocholate (6), and 5a-cholestan-3-one (7) over Adams platinum oxide in methanol in the presence of hydrobromic acid (eq. 5.31 ).98 It is noted that the P-methoxy isomers were produced from the ketones of both 5p (5 and 6) and 5a series (7). 

While no data on the role of 3a-reduced neuroactive steroids in PTSD or its treatment in panic disorder patients have been pubhshed to date, opposite changes to those seen in major depression have emerged. At baseline, patients with panic disorder had significantly increased concentrations of the positive allosteric modulators 3a,5a-THP and 3a,5P-THP, together with sig- 

The taurine residue can also be found as an amide derivative of the 26-carboxylic acid function in the 3p,5a,6p,15a-polyhydroxylated steroids 328 and 329, which were obtained from the starfish Myxoderma platyacanthum [245]. The structures of both compounds were determined from spectral data and chemical correlations. The bile of the sunfish Mola mola has been shown to contain a new bile acid conjugated with taurine (330) together with sodium taurocholate. Compound 330 was identified as sodium 2-[3a,7a, 11 a-trihydroxy-24-oxo-5P-cholan-24-yl]amino]ethane-sulfonate on the basis of its physicochemical data and chemical transformations [246]. 

It is well known that some functional groups, such as an oxo or a hydroxyl, which are located far from the 4,5-double bond e.g., at Cl 1, Cl7, or C20, may have a marked effect on the stereochemistry of hydrogenation of 3-oxo-A4-steroids. In some cases 5a-ketones are formed predominantly.268 A typical example is the hydrogenation of cortisone acetate (116) over 5% Pd-C in ethyl acetate (eq. 3.78).269 No evidence was obtained for the presence of 5p derivative in the product. 

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