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

The synthesis of (23R)- and (23S)-5beta-cholestane-3alpha, 7alpha, 12alpha, 23, 25-pentols is described. Norcholyl aldehyde was converted into the cholestanepentols by a Reformatsky reaction with ethyl bromoacetate followed by a Grignard reaction with methylmagnesium iodide. One of the synthetic pentols, the 23S epimer was identical with a bile alcohol isolated from patients with cerebrotendinous xanthomatosis.
Steroids 1976 May
PMID:Identification of (23S)-5beta-cholestane-3alpha, 7alpha, 12alpha, 23, 25-pentol in cerebrotendinous xanthomatosis. 94 Nov 84

The synthesis of (22R)- and (22S)-5beta-cholestane-3alpha,7alpha,12alpha,22,25-pentols is described. Bisnorcholyl aldehyde was prepared from cholic acid and converted into the cholestane-pentols by a Grignard reaction with 3-methyl-3-(tetrahydropyran-2-yloxy)-butynylmagnesium bromide followed by hydrogenation and acid hydrolysis. One of the synthetic pentols, the 22R-isomer was identical with a metabolite of 5beta-cholestane-3alpha,7alpha,25-triol formed in the rabbit.
Steroids 1976 Mar
PMID:New bile alcohols - synthesis of (22R)- and (22S)-5beta-cholestane-3alpha,7alpha,12alpha,22,25-pentols. 126 99

The 20 alpha-reduced derivative of aldosterone, 20 alpha-dihydroaldosterone, was needed as reference compound in order to continue the studies on 18-hydroxylation in the Y-1 adrenal cell line. It was obtained by reduction of aldosterone with sodium borohydride. Analysis of the products of the reaction as methoxime trimethylsilyl (MO-TMS) derivatives by gas chromatography (GC) and GC-mass spectrometry (GC-MS) showed three possible forms of the compound. Their identification was confirmed by comparison with the products obtained by stereospecific reduction of aldosterone using 3 alpha,20 beta-hydroxysteroid dehydrogenase. Chromatographic behavior and mass spectra are given for the three forms of 20 alpha-dihydroaldosterone as the MO-TMS derivatives; that is, the 18-aldehyde, the 18,11 beta-hemiacetal, and the 11 beta:18,18:20 alpha-acetal. The possible origin of these different forms is discussed as a function of these results and of the results obtained by complementary analysis on high-performance liquid chromatography.
Steroids 1992 Oct
PMID:Chromatographic and mass spectrometric characteristics of 20-dihydroaldosterone. 145 55

The conversion of androgens into estrogen involves three distinct generic reactions which are catalyzed by a single P450 enzyme (aromatase or P450(aromatase)). The first step in the process is the conversion of 19-methyl into a hydroxymethyl group which requires NADPH + O2, thus representing the well-known hydroxylation process. The next stage, converting the -CH2OH into -CHO, also requires NADPH + O2 and may be rationalized either through a second hydroxylation reaction producing a gem-diol, CH(OH)2 (which dehydrates to the aldehyde), or via another route. The final stage in the process again uses NADPH + O2, culminating in the release of C-19 as formate. Our extensive studies using precursors containing 2H, 3H, and 18O have shown that the carbonyl oxygen of the 19-aldehyde group is the one that was introduced in the first step as the hydroxyl group. The aldehydic oxygen along with another, from O2, used in the third step of the process, is incorporated into the released formate. It was found that at each stage of the process, oxygen atoms were introduced or transferred as "whole numbers." In light of these data, mechanisms in which H2O is used to promote the C-10-C-19 bond cleavage or those in which the conversion of the 19-oxoandrostenedione into estrogen is considered to occur via the sequence -CHO----(-)CH(OH)2----estrogen are eliminated. In addition, our mechanistic analysis makes it unlikely that 1 beta-, 2 beta-, or 10 beta-hydroxysteroids serve as intermediates in estrogen biosynthesis. We consider a free radical mechanism for the hydroxylation process.
Steroids 1990 Apr
PMID:Studies on estrogen biosynthesis using radioactive and stable isotopes. 218 83

The effects of ketoconazole, an inhibitor of cytochrome P-450, on the metabolism of the cholesterol precursors lanosterol, dihydrolanosterol, lanost-8-en-3 beta,32-diol, and 3 beta-hydroxylanost-8-en-32-al were investigated in subcellular fractions of rat liver and in rat hepatocytes in culture. At low (1-2 microM) concentrations of the drug, the oxidative demethylation of lanosterol was inhibited by about 70% in the subcellular fractions but there was no effect on the metabolism of the 3 beta, 32-diol or the 32-aldehyde. Higher drug concentrations (10-20 microM) were required to inhibit the oxidative metabolism of these cholesterol precursors. Similar results were obtained during longer-term incubations using hepatocytes in culture medium, but higher concentrations of ketoconazole were required to effect the same degree of inhibition of each precursor. In the subcellular fractions, dihydrolanosterol, the 3 beta,32-diol and the 32-aldehyde were each metabolized to more polar sterols, in addition to cholesterol. Ketoconazole also inhibited the formation of these polar substances.
Steroids
PMID:Oxidative metabolism of cholesterol precursors: sensitivity to ketoconazole, an inhibitor of cytochrome P-450. 279 48

Synthesis of the alpha,beta-unsaturated analogues of cholic acid, deoxycholic acid, chenodeoxycholic acid, and ursodeoxycholic acid is described. Each common bile acid was converted to the corresponding C22 aldehyde which was then converted to the delta 22 bile acid by Wittig reaction with methyl (triphenylphosphoranylidene)acetate. The synthetic unsaturated bile acids were characterized by thin-layer chromatography, gas-liquid chromatography, and mass spectrometry.
Steroids
PMID:Synthesis of alpha,beta-unsaturated C24 bile acids. 383 14

A procedure is described for the chemical synthesis of steroidal-20-oxo-21-oic acids and -17 alpha(-hydroxy-20-oxo-21-oic acids. Corticosteroid derivatives containing the 20-oxo-21-aldehyde side chain are oxidized with freshly generated silver oxide in dilute aqueous sodium hydroxide.
Steroids 1983 Nov
PMID:An improved method for the chemical synthesis of steroidal 20-oxo-21-oic acids. 668 Sep 28

This paper describes three simple and short methods for the conversion of cholic acid into cholylaldehyde with protected hydroxyl groups. The first method involves lithium aluminum hydride reduction of the tetrahydropyranyl ether of methyl cholate and oxidation of the resulting primary alcohol with pyridinium chlorochromate. The second method employs diborane for the reduction of the -COOH group to the -CH2OH group, while the third method involves the reduction of 3 alpha, 7 alpha, 12 alpha-triformyloxy-5 beta-cholan-24-oic acid (as the acid chloride) directly into 3 alpha, 7 alpha, 12 alpha-triformyloxy-5 beta-cholan-24-al with TMA-ferride (tetramethylammonium hydridoirontetracarbonyl). The aldehyde obtained by any of the above methods underwent smooth Reformatsky reaction with ethyl alpha-bromopropionate to yield 3 alpha, 7 alpha, 12 alpha, 24 xi-tetrahydroxy-5 beta-cholestan-26-oic acid.
Steroids 1982 Jun
PMID:Improved synthesis of 3 alpha, 7 alpha, 12 alpha, 24 = xi-tetrahydroxy-5 beta-cholestan-26-oic acid. 715 40

The synthesis of a 16 alpha-(bromoalkylamide) derivative of estradiol (N-butyl, N-methyl, 11-[3',17' beta-(dihydroxy)-1',3',5' (10')-estratrien-16' alpha-yl]-9(R/S)-bromo undecanamide) was performed by two different approaches starting from estrone. Each approach has the same key intermediate, containing an aldehyde group, but differs by the bromination step and the timing of formation of the amide group. This compound was found to cause, at 100 microM, a complete inhibition of 17 beta-hydroxysteroid dehydrogenase (17 beta-HSD) responsible for the interconversion of estrone and estradiol. The corresponding IC50 value was 10.6 microM. In the estrogen-sensitive ZR-75-1 human breast cancer cell line, this estradiol derivative has no estrogenic activity at 30 nM and only a minimal estrogenic activity (10% above the basal level) at 1 microM. At this latter concentration, this compound causes a 28% inhibition of 0.1 nM E2-induced cell proliferation (antiestrogenic activity). Thus, the introduction of a side-chain with a secondary bromide and a butyl methyl amide group at the 16 alpha-position of estradiol has two interesting effects; namely an inhibition of cytosolic 17 beta-HSD and a blockade of the estrogenic effect of estradiol.
Steroids 1994 Sep
PMID:N-butyl, N-methyl, 11-[3',17' beta-(dihydroxy)-1',3',5'(10')-estratrien-16' alpha-yl]-9(R/S)-bromo undecanamide: synthesis and 17 beta-HSD inhibiting, estrogenic and antiestrogenic activities. 784 36

A synthesis of (19E)-3 beta,17-dihydroxy-20-oxopregn-5-en-19-al 19-(O-carboxymethyl)oxime (15), is reported. Hydride reduction of ketone 1 gave the (20R)-hydroxy derivative 2 as the main product. Formylation of 2 followed by cleavage of the epoxide ring and mild Jones oxidation afforded aldehyde 6. Oximation with (O-carboxymethyl)hydroxylamine and subsequent methylation yielded methyl ester 8 which was selectively hydrolyzed to alcohol 9 and oxidized to ketone 10. Enolacetylation, epoxidation, and hydrolysis led to the desired 19-(O-carboxymethyl)oxime derivative of 17-hydroxypregnenolone 15.
Steroids 1994 Dec
PMID:Synthesis of (19E)-3 beta,17-dihydroxy-20-oxopregn-5-en-19-al 19-(O-carboxymethyl)oxime, new steroidal hapten for 17-hydroxypregnenolone. 790 Jan 68


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