High-field NMR studies of 3beta-tetrahydropyranyloxy steroids.

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.

Steroids 54. Amino acylamidosteroids.

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.

Complete 1H and 13C NMR spectra of pregnenolone.

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.

Novel synthesis of cholesterol analogs: condensation of pregnenolone with dihydropyran or dihydrofuran.

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)

The preparation of 2,4-dibromoestra-1,3,5(10),6-tetraene-3,17 beta-diol diacetate.

[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.