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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of the C-3 substituent on the reaction of androst-5-enes with mercury(II) trifluoroacetate in dichloromethane (modified Treibs oxidation) was investigated. 3 beta-Acyloxyandrost-5-en-17-ones gave 3 beta-acyloxy-6 beta-hydroxyandrost-4-en-17-ones accompanied by 3 beta-acyloxy-6-chloromercuriandrost-5-en-17-ones. 3 beta-Acetoxy-6 beta-trifluoroacetoxyandrost-4-en-17-one and 3 beta-acetoxy-4 beta-trifluoroacetoxyandrost-5-en-17-one were revealed to be intermediates in the reaction. The formation of the chloromercury steroids indicated participation in the reaction by the solvent. With 3 alpha-acetoxyandrost-5-en-17-one as substrate, a complete reversal in the product distribution was observed. 3 beta-Haloandrost-5-en-17-ones gave mainly products that reflected SN1 substitution of the halide. 3 beta-Hydroxy- and 3 beta-trifluoroacetoxyandrost-5-en-17-ones were formed. 3 beta-Methoxyandrost-5-en-17-one afforded in nearly identical yields androst-4-ene-3,17-dione, 3 beta-methoxy-6 beta-hydroxyandrost-4-en-17-one, 3 beta-methoxy-6-chloromercuriandrost-5-en-17-one and 6 beta-hydroxyandrost-4-ene-3,17-dione while androst-5-en-17-one yielded 3 beta,6 beta-dihydroxyandrost-4-en-17-one, androst-5-ene-7,17-dione and androst-4-ene-3,17-dione. The effects of solvent and other mercury salts on the reaction were also studied. Treibs oxidation was successful in chloroform, carbon tetrachloride, and dibromomethane, but not in other solvents tested. 3 beta-Acetoxy-6-bromomercuriandrost-5-en-17-one was obtained in dibromomethane. Replacement of the reagent by mercury(II) trichloroacetate altered the intermediates formed but not the products. Mercury(II) tribromoacetate was unreactive, however.
Steroids 1998 Dec
PMID:The scope and limitations of the reaction of delta 5-steroids with mercury(II) trifluoroacetate. 987 Feb 62

Steroids from Solanum nudum (SNs) have demonstrated antiplasmodial activity against erythrocytic stages of the Plasmodium falciparum strain FCB-2. It is well known that steroids can alter the membrane function of erythrocytes. Thus, we assessed alterations in the membranes of uninfected red blood cells, the parasite invasiveness and the solute-induced lysis of parasitised red blood cells (pRBCs). induced by SNs. We found that most merozoites were unable to invade SN-treated erythrocytes. However, transmission electron microscopy revealed no effect on the morphology of uninfected erythrocytes treated with either SN2 or diosgenone and neither SN induced haemolysis of uninfected erythrocytes. SN2 and SN4 inhibited isosmotic sorbitol and alanine-induced haemolysis of pRBCs. In contrast, diosgenone and SN1 did not inhibit solute-induced haemolysis. The inhibition of solute-induced lysis of parasitised erythrocytes by SN2 and SN4 suggest an action of these SNs on new permeability pathways of pRBCs.
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PMID:Effect of Solanum nudum steroids on uninfected and Plasmodium falciparum-infected erythrocytes. 1982 Aug 25