5a-Cholesta-1,3-diene

In contrast to earlier literature reports, photo-oxygenation of 17/3-hydroxyoestr-5(10)-en-3-one has been shown not to be stereospecific, since a mixture of 10a- and 10/3-hydroperoxy-3-oxo-A -compounds was obtained. Thermal rearrangement of these products gave the 10a- and 10/3-hydroxy-3-oxo-A -compounds. Photo-oxygenation of 5a-cholesta-1,3-diene led only to cholesta-1,4-... 

Purified cholesterol, all known initial and subsequent oxidation products of cholesterol and some related compounds were tested cholest-5-en-3-one 7a-diol 73-diol 7-keto cholesta-3,5-dien-7-one a-epoxide triol cholest-4-en-3-one 63-hydroperoxycholest-4-en-3-one 63 hydroxycholest-4-en-3-one cholest-4-ene-3,6-dione cholest-5-ene-33,43 diol 5a-cholest-6-ene-33,5a-diol 53 cholestan-33-ol cholesta-1,4-dien-3-one 5a-cholest-7-eii-33 ol cholesta-7,9-dien-33-ol acetate 7,8,9,11-diepoxy-22-isoallospirostan-33 ol acetate cholesteryl acetoace-tate and cholesteryl isoheptylate. Many were carcinogenic when administered subcutaneously into Marsh-Buffalo mice with sesame oil as the vehicle a-epoxide, 63-hydroperoxycholest-4-en-3-one and cholest-4-en-3,6-dione were most potent (34-66% incidence of fibrosarcoma verses 1.4% for vehicle control). All share the property of oxygen linkage at carbon 6. 63-hydroxycholest-... 

At low temperatures RuO, as RuO /aq. Na(IO )/acetone/-70°C epoxidised some conjugated sterols. Thus 5a-cholesta-7,9(ll)-dien-3p-yl acetate (1), when so treated, gave 3p-acetoxy-9-oxo-9,ll-seco-5a-cholest-7-en-ll-al (2) together with three 8a,9a epoxysterols (3-5) (Fig. 3.1) [76, 77],... 

C29H48O2S, Cholestan-4-one-3-spiro(2,5-oxathiolane), 33B, 201 C2 9H49CIO2 r 3p-Acetyloxy-14-chloro-5a,14, 17a-cholestane, 41B, 614 C29Hso02r 9, 10a-Cholesta-5,7-diene-3 -ol ethanol solvate, 40B, 503 C30H33BrF403, 3/3-(p-Bromobenzoyloxy)-androst 5-eno-[16a,17-d]-2 ,2 ,3, 3 -tetrafluoro-2, 3 -dihydro-6-methylpyran, 37B, 302 C30H4 2O7 r 6a,7a 22,26 24,25-Triepoxy-5,26-dihydroxy-5a-ergost-2-en-1-one acetate, 42B, 411... 

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