RESUMO
Comprehensive NMR studies were carried out on 3beta-hydroxy-pregnene and cholestene analogs, each containing a tetrahydropyranyl ether group at the 3-position. Two-dimensional NMR experiments (COSY, TOCSY, HSQC, and HSQC-TOCSY) permitted the complete assignments of both the (1)H and (13)C resonances of these derivatives in deuterated benzene or chloroform. The aromatic solvent-induced NMR signal shifts (ASIS) were also investigated.
Assuntos
Colestenos/química , Espectroscopia de Ressonância Magnética , Pregnenos/química , Piranos/químicaRESUMO
Aminosteroids were prepared and acylated with protected amino acids by means of the mixed anhydride or the active ester method. The tert-butyloxycarbonyl- (BOC) protecting group was eliminated by acidolysis, and the benzyloxycarbonyl- (Z) group by catalytic hydrogenation. 3 beta- and 6 beta-Glycylamidosteroids were prepared by indirect amination of chloroacetamido derivatives, formed by the Ritter reaction on the corresponding 3 alpha,5 alpha-cyclo and 5 alpha,6 alpha-epoxy steroids. Water-soluble double salts were produced from the compounds for pharmacological investigations.
Assuntos
Aminoácidos/química , Esteroides/síntese química , Androstanos/química , Pregnanos/química , Pregnatrienos/química , Solubilidade , Esteroides/químicaRESUMO
Assignments for signals from 1H and 13C in the NMR spectra of pregnenolone (1), 16-dehydropregnenolone (2), and the 3-acetate of 1 (3) were validated by two-dimensional correlated spectroscopy (2D COSY) and heteronuclear single quantum coherence (HSQC). The narrow band of overlapping signals from H-7, H-2, and H-4 was resolved by exploiting three-bond coupling in the 2D COSY spectra and heteronuclear correlation. Assignments were based on high intensity cross peaks from long-range coupling by H-18 with H-17 and H-12 (axial). Similar cross peaks were observed for H-17 with H-21. Low intensity cross peaks were seen for H-4 coupled with H-6 and H-7, and also H-16 (quasi-axial) with H-14 of 1 and 3. Assignments based on 2D COSY spectra were confirmed by correlation peaks from HSQC. This now corrects the earlier conflicts among assignments reported for 13C signals of 1 and 3. Accurate assignments were similarly derived for signals from C-2, C-7, C-8, and C-21 of 1 and 3, and C-15 and C-16 of 1, 2, and 3. The complete sets of 1H and 13C NMR data for pregnenolone, pregnenolone 3-acetate, and 16-dehydropregnenolone serve as reference standards.
Assuntos
Espectroscopia de Ressonância Magnética , Pregnenolona/química , Isótopos de Carbono , Hidrogênio , Pregnenolona/análogos & derivadosRESUMO
Pregnenolone 3-(2'-tetrahydropyranyl) ether (1) was condensed with 3,4-[2H]dihydropyran to mainly give (20R)-[6'-(3',4'-[2'H]dihydropyranyl)]-pregn-5-ene-3 beta,20-diol 3-(2'-tetrahydropyranyl) ether (20R-3), according to nuclear magnetic resonance (NMR). Cold, dilute HCl in ethanol removed the tetrahydropyranyl group at C-3 and also opened the dihydropyranyl ring at the C-20 position of 20R-3 to give (20R)-27-norcholest-5-en-22-one-3 beta,20,26-triol (20R-5). Analogous results were obtained by condensing pregnenolone 3-acetate with 3,4-[2H]dihydropyran to provide (20R)-[6'-(3',4'-[2'H]dihydropyranyl)]-pregn-5-ene-3 beta,20-diol 3-acetate (20R-4). Acid-catalyzed opening of the dihydropyranyl ring at C-20 in 20R-4 yielded 20R-7, which, on acetylation followed by crystallization, provided (20R)-27-norcholest-5-en-22-one-3 beta,20,26-triol 3,26-diacetate (20R-8), identical to the diacetate made from 20R-5. Varying the reaction sequence beginning with 20(R,S)-4 gave an 84:16 ratio of 20R to 20S in a mixture of 20(R,S)-8, according to NMR analysis. Crystallization of the mixture from methanol provided pure 20R-8. Condensing 2,3-dihydrofuran and 1 for producing (20R)-[5'-(2',3'-dihydrofuranyl)]-pregn-5-ene-3 beta,20-diol 3-(2'-tetrahydropyranyl) ether (6) gave instead (20R)-26,27-bisnorcholest-5-en-22-one-3 beta,20,25-triol 3-(2'-tetrahydropyranyl) ether (20R-9) by partial hydrolysis during workup. Treating 20R-9 briefly with dilute HCl produced (20R)-26,27-bisnorcholest-5-en-22-one-3 beta,20,25-triol (20R-10).(ABSTRACT TRUNCATED AT 250 WORDS)
Assuntos
Colesterol/análogos & derivados , Furanos/química , Pregnenolona/química , Piranos/química , Colesterol/síntese química , Espectroscopia de Ressonância MagnéticaRESUMO
[2,4,6,7-3H4]Estradiol is used for the quantitative determination of estradiol receptors. The synthesis of 2,4-dibromoestra-1,3,5(10),6-tetraene-3,17 beta-diol 3,17-diacetate, the convenient precursor of [2,4,6,7-3H4]estradiol, is described. 6-Alkoxy compounds were also prepared and investigated.