Steroids, nitro reduction

Some aminobenzoic acid diuretics containing the thiophen ring have also been studied. The syntheses and lipid-lowering properties of (203) and (204) have been described. 3-j8-(2-Thienyl-alanine-8-lysine)vasopressine has been synthesized by the solution technique. A comparison of the bioavailability of [2,5- C]thiophen after oral and rectal administration in mice has been reported. The nitro-reduction of carcinogenic 5-nitro-thiophens by rat-tissues has been studied. Thiophen-ring-containing compounds with antiradiation, antidepressant, antiparasitic, " antibacterial, - antiviral, and broncho-dilator activity have been studied. A thia-steroid, 14,15-dehydro-A-nor-3-thiaequilenin, has been synthesized. In connection with studies on the syn-... 

Iodotrimethylsilane generated in situ from chlorotrimetylsilane and sodium iodide effects the reduction of nitroalkenes into ketones at 0 °C. This method is useful for the conversion of nitro steroids or nitro terpenoids to the corresponding ketones (Eq. 6.24).43... 

The reduction of functional groups with sulfurated horohydrides has been reviewed by Lalancette et al. The reagent is particularly useful for selective reductions. Thus selective reduction of a nitro, an oxime, or a nitrile group in the presence of an ester group is possible. In the case of steroidal ketones, the carbonyl group at C is the most reactive site selective reduction of a C -carbonyl group in the presence of other carbonyls at C, I, C,2, C,7, or Cjo is possible. The alcohol obtained is the equatorial isomer. Aldehydes can be reduced selectively in the presence of a carhonyl group if the molar ratio of NaBHjS, is kept at a suitable value. 

Catalyzed reductions with ammonium formate proceed with retention of configuration, at least for the case of nitro compounds. Treatment of steroid derivative (12) with ammonium formate in methanolic solution and a catalytic amount of palladium on charcoal gave exclusively amino steroid (13), as shown in equation (13). A similar technique has been used to produce members of the ephedrine family. 

Various studies have been devoted to the synthesis of amino-substituted steroids. These compounds can be prepared either from an alcohol, by displacement of a toluene-p-sulphonyl group by an amine, ° from a ketone, either by reduction of the corresponding oxime ° ° or by Beckmann rearrangement of 20-keto-oximes, ° or by catalytic reduction of a nitro-group. ° Another... 

Reduction of nitroolefins. Hassner and Heathcock found that 6-nitrocholesteryl acetate can be reduced with sodium borohydride in ethanol to the saturated 6a-nitro-5a-steroid. 

Two novel complex hydrides are likely to find applications in steroid chemistry lithium perhydro-9b-boraphen yl hydride affords unusually high proportions of axial alcohols in model compounds sodium bis(methoxyethoxy)aluminium dihydride, Na (MeOCH2CH20)JAlH2, a very safe and convenient substitute for lithium aluminium hydride, readily reduces not only ketones but also acids, nitro-compounds, oximes, amides, lactones, etc. An improved procedure for Clemmensen reduction of steroid ketones involves saturating an ethereal solution with hydrogen chloride while stirring with zinc. 5a-Cholestane was obtained from the 3-one in 89% yield. ... 

The phospholipase Aj inhibitor dibromoaceto-phenone, the anti-inflammatory steroid fluocino-lone acetonide or the lipoxygenase inhibitor nordi-hydroguiaretic acid just prior to intraperitoneal injection of 100 ng 12-0-tetradecanoylphorbol-13-acetate into unmanipulated CD-I female mice resulted in a dose-dependent decrease in the number of peritoneal exudate cells producing superoxide anion radical as assessed by the reduction of nitro-blue tetrazolium, while the cycloxygenase inhibitor indomethacin had no effect on the number of formazan-positive peritoneal exudate cells caused by PMA treatment (Czerniecki and Witz 1989). 

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