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The applicability of homonuclear gradient enhanced NMR experiments is demonstrated in the structure determination of steroid derivatives using stigmasterol as a model compound. High resolution 1 H NMR spectra of steroids very often display well resolved multiplets usually in the low-field region, and these signals can be used as starting points in several selective NMR experiments to study...
Inclusion complexes of several steroid derivatives with β-cyclodextrin (7) were studied in dimethylsulfoxide solution. The investigated molecules were ketosteroids with different functional groups on the skeleton: 3β-acetoxypregn-5-en-20-one (1), 3β-acetoxypregna-5,16-dien-20-one (2), 3β-acetoxyandrost-5-en-17-one (3), 3β-hydroxyandrost-5-en-17-one (4), 5α-androstane-3,17-dione (5) and 17β-hydroxyandrost-4-en-3-one...
Reactions of 16-hydroxymethylene- and 16-aminomethylene-3β-hydroxy-5-androsten-17-one with formamide and guanidine were carried out resulting in the formation of [16,17-d]-pyrimidine rings. Advanced two-dimensional NMR methods were used to investigate the structure of the products. Homonuclear-, and heteronuclear chemical shift correlation experiments yielded the complete 1 H-, 13...
Heating (20R)-3β,20,26-trihydroxy-27-norcholest-5-en-22-one (1) with hydrazine and KOH at 160 o C completely converted the steroid to a diastereoisomeric mixture of the new (20R,22RS)-27-norcholest-5-ene-3β,20,22-triols (2). Exclusive formation of 2 suggests that the expected Wolff-Kishner reduction to a methylene group at the C-22 ketone in 1 was diverted to the C-26 position by a 1,5-hydride...
The four possible isomers 16β-hydroxymethyl-5α-androstane-3β,17β-diol 1, 16α-hydroxymethyl-5α-androstane-3β,17β-diol 2, 16β-hydroxymethyl-5α-androstane-3β,17α-diol 3 and 16α-hydroxymethyl-5α-androstane-3β,17α-diol 4 with proven configuration were converted into the corresponding 16β-methyl-5α-androstane-3β,17β-diol 5, 16α-methyl-5α-androstane-3β,17β-diol 6, 16β-methyl-5α-androstane-3β,17α-diol 7,...
Comprehensive NMR studies were carried out on 3β-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...
Assignments for signals from 1 H and 13 C 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...
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