Pregnane-3a,20 3-diol

C21H36O2. M,p. 238°C. There are four isomeric pregnane-3,20-diols differing only in the orientation of the hydroxyl groups at positions 3 and 20 and with the 5/ configuration. Only the 3a,20a occurs naturally. It is formed by reduction of progesterone in the liver and is the chief urinary metabolite of it, being... 

Cyclohex-2-enone- bicyclo [3.1.0] hexan-2-one rearrangement, 318 3a,5o -Cyclo-6/3,19-oxidocholestane, 268 18,20-Cyclo-5a-pregnane-3, 20-diol 3-acetate, 264... 

Treatment of progesterone with trifluoroacetic acid and triethylsilane in dichloromethane followed by saponification of the mixture of the trifluoroacetate ester intermediates of 5-/3-pregnane-3a,20/3-diol and 5-j6-pregnane-3a,20a-diol and Jones oxidation yields 5-/3-pregnanedione in 65% yield (Eq. 81).238... 

A7. Arias, I. M., and Gartner, L. M., Production of unoonjugated hyperbilirubinaemia in full-term new-born infants ollowing administration of pregnane-3a,20 8-diol. Nature (London) 203, 1292-1293 (1964). 

More recently, Lewbart3 reported selective hydrolysis of the acetonide group of 17,20 -isopropylidenedioxy-5/3-pregnane-3a,21-diol diacetate (5) with retention of the primary and secondary acetoxy groups. 

Synthesis of Cortisone from Pregnane-3a,21-diol-ll,20-dione 21-... 

The subsequent stages from pregnan-3a-ol-ll,20-dione acetate (I) to cortisone have been recorded by Kritchevsky et al. (1952) (Fig. 4). The enol acetate (II) of I upon treatment with perbenzoic acid forms the epoxide (III), which without isolation is hydrolyzed directly to pregnane-3a,17 -diol-ll,20-dione (IV). Bromination at C-21 (V) and mild treatment with alkali produces the 21-hydroxy derivative (VI), which is oxidized with N-bromoacetamide to dihydrocortisone (VII). Bromination (at C-4) of the 21-acetate of VII followed by dehydrobromination with semi-carbazide leads to the semicarbazone of cortisone acetate (VIII), which can be cleaved in a facile manner with pyruvic acid to cortisone acetate. Under suitable conditions, it is possible to accomplish the oxidation at C-3 and bromination of the ketone at C-4 in one step by means of N-bromoacetamide (Hershberg, Gerold, and Oliveto, 1952b). This synthesis of cortisone acetate from desoxycholic acid outlined in Figs. 3 and 4 is one of the most efficient bile acid processes, since it does not suffer from the difficulties outlined under Section II.2. 

Alternatively (Kendall, 1952), the diene (XI) is again brominated with N-bromosuccinimide to XII and after treatment with potassium acetate followed by ozonization affords in excellent 3deld 12 -bromo-pregnane-3a,21-diol-ll,20-dione diacetate (XV) and thence by debromination the halogen-free derivative (XVI). Both XV and XVI are valuable intermediates in two important syntheses of cortisone (Figs. 6 and 7). 

Pregnane-3a,21-diol-20-one-21-acetate, infrared absorption spectrum, VII, 334 Pregnane-3( ),20(a)-diol-ll-one diacetate,... 

Fig. 125. Lengths of run of sterols and steroids of various polarities in 6 solvent systems of different eluotropic properties (Nos. 1—6 below). Substances 1 tetra-hydrocortisol 2 cortisol 3 cortisone 4 corticosterone 5 oestradioI-17/ 6 5/5-pregnane-3a,20a-diol 7 oestrone 8 testosterone 9 pregn-5-en-3j5-ol-20-one 10 androst-4"ene-3,17-dione ii deoxycorticosterone 12 progesterone 73 cholesterol 14 cholesteryl acetate 15 cholestane...

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