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At least 217 records · Page 12Linked to original sources
PubMed1979

Lumi-mestranol and epi-lumi-mestranol.

Treatment of lumi-estrone 3-methyl ether (I) with acetylene gave the C-17-epimeric compounds lumi-mestranol (3-methoxy-17 alpha-ethynyl-13 alpha-estra-1,3,5(10)-trien-17 beta-ol, III ) and epi-lumi-mestranol (3-methoxy-17 beta-ethynyl-13 alpha-estra-1,3,5(10)-trien-17 alpha-ol, IV). The structures of the two isomers were assigned on the basis of their molecular rotations and shift-reagent experiments in the NMR. The irradiation of estrone 3-methyl ether (II) to provide compound I was investigated in two solvent systems. Minor products of these reactions were the seco-steroids VII, VIII and X.

Acetylene↗
PubMed1982

Inactivation of delta5-3-ketosteroid isomerase(s) from beef adrenal cortex by beta, gamma-acetylenic ketosteroids.

The beta, gamma-acetylenic ketosteroids, 5-10-seco-19-norpregn-5-yne-3,-10,20-trione approximately 1 and 5,10-secoestr-5-yne-3,10,17-trione approximately 2 irreversibly inactivate both the C19-and the C21-delta 5-3-ketosteroid isomerase activities of beef adrenal cortex microsomes. At saturating concentrations of inhibitor half-lives of these enzyme activities vary from 45 to 240 s. It is uncertain whether the enzyme generates its own alkylating agent by isomerizing compounds approximately 3 and approximately 4 to the corresponding allenic ketones, namely (4R)-5,10-seco-19-norpregn-4,5-diene-3,10,20-trione approximately 3 and (4R)-5,10-secoestra-4,5-diene-3,10,17-trione approximately 4 since these are formed spontaneously in the buffer used to stabilize enzyme activity. In the presence of catalytic quantities of adrenal enzyme compound approximately 4 is a powerful competitive inhibitor for both 5-androstene-3,17-dione (Ki 8.0 microM) and 5-pregnene-3,20-dione (Ki 3.5 microM) indicating that the eventual alkylating event is active site-directed. The differences in Ki values and half-lives for inactivation support the view that the C19- and C21-delta 5-3-ketosteroid isomerase activities do not reside at the same catalytic site in beef adrenal cortex microsomes.

Adrenal Cortex↗
PubMedDate not supplied

Preparation of 14,15-secoestra-1,3,5(10)-trien-15-ynes, inhibitors of estradiol dehydrogenase.

The conversion of estrone to 14,15-secoestratrien-15-ynes, inactivators of estradiol dehydrogenase from human term placenta, is described. The optically pure precursor 7-acetoxy-octahydro-2-phenanthrenecarboxylic acid methyl ester is prepared from estrone in five steps and 40% yield. The unsubstituted propargylic secoestratriene diol, a mechanism-based inactivator of estradiol dehydrogenase, and the corresponding acetylenic ketone, an affinity label inactivator of the same enzyme, arise from the phenanthrene ester in three and four steps. The propargylic secoestratriene diol also competes with [3H]estradiol for binding to calf uterus estrogen receptor and possesses weak uterotrophic activity.

17-Hydroxysteroid Dehydrogenases↗
PubMed1990

Studies of the synthesis of biomarkers. VII. Synthesis of 5 alpha-(17R,20R)-14,15-secocholestane.

5 alpha-(17R,20R)-14,15-Secocholestane (12) was synthesized from cholesterol (1) in 12 steps. The key intermediate, 5 alpha-cholest-14-en-3 beta-yl acetate (4), underwent ozonization, reduction, hydrolysis, and oxidation to provide 5 alpha-14,15-secocholesta-3,14,15-trione (8). One of the Clemmensen reduction products of 8 is 5 alpha(17R,20R)-14,15-secocholest-15-ol (11); treatment of the alcohol (11) with tosyl chloride and subsequent reduction with lithium aluminum hydride yielded the target molecule (12).

Aluminum↗
PubMed1992

Studies of the synthesis of biomarkers. XI. Synthesis of 4,5-secocholestane and 4-methyl-4,5-secocholestane.

4,5-Secocholestane (1a) and 4-methyl-4,5-secocholestane (1b) were synthesized from cholesterol (2) in five and seven steps, respectively. The key intermediate, 5-oxo-4,5-secocholestan-4-al (7) was reduced by the Clemmensen method to afford 1a. Meanwhile, 7 underwent selective Wittig reaction, Clemmensen reduction, and hydrogenation to give another target molecule, 1b. The structure of an unknown biomarker was shown to be different from the proposed 1a by gas chromatographic and mass spectrometric comparison.

Cholestanes↗
PubMed1992

Studies of the synthesis of biomarkers. X. Synthesis of 13,17-secodiacholestanes.

13,17-Secodiacholestanes (6) were synthesized from cholesterol (1) in six steps. The key intermediates, (20R)- and (20S)-diacholest-13(17)-enes (3a and 3b), underwent ozonization and reduction to provide (20R)- and (20S)-13,17-secodiacholesta-13,17-dione (5a and 5b), respectively. On Clemmensen reduction, the diones (5a and 5b) yielded the target molecule 6. The structure of an unknown biomarker was shown to be different from the proposed 6 by gas chromatographic/mass spectrometric comparison.

Cholestanes↗
PubMed1992

Two new 9,11-secosterols from the marine sponge Spongia officinalis. Synthesis of 9,11-seco-3 beta,6 alpha,11-trihydroxy-5 alpha-cholest-7-en-9-one.

Two new 9,11-secosterol, 9,11-seco-3 beta,6 alpha,11-trihydroxy-5 alpha-cholest-7-en-9-one (2) and 9,11-seco-3 beta,6 alpha,11-trihydroxy-24- methylene-5 alpha-cholest-7-en-9-one (3), have been isolated from the marine sponge Spongia officinalis and their structures elucidated by analysis of spectral data including 1H nuclear magnetic resonance correlation spectroscopy (COSY) experiments. Partial synthesis of 2 starting from 3 beta,6 alpha-dihydroxy-9-oxo-9,11-seco-5 alpha-cholest-7-en-11- al (1) confirmed the structure assignment.

Animals↗
PubMed1992

Antihormonal properties of some new A-homo-B, 19-dinor steroids of the androstane series.

On solvolysis of Westphalen-type steroids with a leaving group in the position 6 beta (e.g., 2), products of elimination (followed by rearrangement and fragmentation of the steroid skeleton) were prepared (e.g., 4 and 5). These products were subsequently converted to suitable analogs of the compound, which has been reported to promote hair growth (1). Compounds 11 to 13 exhibited strong antiandrogenic activity in vivo; however, this activity could not be interpreted either in terms of inhibition of 5 alpha-reductase or by strong binding to an androgen receptor.

Androgen Antagonists↗
PubMed1993

The ozonation of cholesterol: separation and identification of 2,4-dinitrophenylhydrazine derivatization products of 3 beta-hydroxy-5-oxo-5,6-secocholestan-6-al.

The ozonation products of cholesterol, which are of interest as possible biomarkers of O3 exposure, were studied by derivatization with 2,4-dinitrophenylhydrazine (DNPH). The DNPH derivatization of 3 beta-hydroxy-5-oxo-5,6-secocholestan-6-al (2) produces the expected trans (3b) and cis (3c) derivatives of 3 beta-hydroxy-5-oxo-5,6-secocholestan-6-al, and the unexpected DNPH derivative of 3,5-dihydroxy-B-norcholestane-6-carboxaldehyde (3a). The structures of 3a, 3b, and 3c were identified with 1H nuclear magnetic resonance (NMR), 13C NMR, DEPT, COSY, and H-C correlation two-dimensional NMR techniques, and by comparison with the spectra of known compounds. A possible mechanism involving an enamine functionality is proposed for the formation of 3a. The ratio of 3a/(3b + 3c) depends on the concentration of acid used and the reaction time.

Cholestanones↗
PubMed1995

Crystal structure of doisynolic acid and the structure of other products formed during its synthesis.

The crystal structure of the D-seco-estrogen doisynolic acid shows it to have the natural S configuration at the position derived from C-14 in estrone. Two major by-products during the synthesis of doisynolic acid from estrone are shown to be dimeric steroids. One is an aldol condensation product, and the other appears to arise from an alkaline cleavage of the aldol product.

Crystallization↗