Hydroxy-steroids. Part XI. The preparation and infrared spectra of vicinal cholestanediols
作者:C. W. Davey、E. L. McGinnis、J. M. McKeown (née Chancellor)、G. D. Meakins、M. W. Pemberton、R. N. Young
DOI:10.1039/j39680002674
日期:——
Twenty-eight vicinal cholestanediols (positions 1,2; 2,3; 3,4; 4,5; 5,6; 6,7; and 7,8) have been prepared by unambiguous routes starting from the corresponding olefins. The O–H stretching bands of dilute solutions of these diols and of seven reference compounds have been examined under high dispersion. Characteristic differences between ax,ax, ax,eq, and eq,eq compounds were observed. It was concluded
Some unexpected products from the treatment of organoboranes from α,β-unsaturated ketones with acetic acid–acetic anhydride
作者:K. Bailey、T. G. Halsall
DOI:10.1039/j39680000679
日期:——
5β-triacetoxy-10β-methyl-trans-decalin was obtained although no specific oxidising agent was used. Under similar conditions 10-methyl-Δ1(9)-octalin-2-one and cholest-4-en-3-one also afforded oxidation products, viz. 1α,2β-diacetoxy-10β-methyl-trans-decalin (26% yield) and 3β,4α-diacetoxy-5α-cholestane (19% yield). No evidence has yet been obtained concerning the mechanism whereby the organoboranes are oxidised
In order to clarify the steric mechanism for biotransformation of ⊿5-3β-hydroxysteroid into ⊿4-3-ketosteroid the metabolic fate of hydrogen at C-4 during conversion of cholesterol into cholestenone by 3β-hydroxysteroid oxidase has been investigated. Of three substrates required for this purpose 4α-d1-cholesterol was prepared through 4-d1-cholest-4-en-3β-ol tert-butyldimethylsilyl ether as a key intermediate. The substrate was incubated with the enzyme, and the content and locality of deuterium in resulting cholestenone were determined by inspection of the mass, nuclear magnetic resonance, and infrared spectra. The transformation products formed from 4α-and 6-deuterated cholesterols retained the label almost intact, while that derived from 4β-d1-cholesterol showed ca. 50% retention of the heavy isotope at 6β. Incubation studies using 6β-d1-cholestenone as a substrate implied that a 50% loss of the label would be ascribable in part to the exchange with the incubation medium under the enzymatic control. These results led to a definite conclusion that 4β-hydrogen was transferred stereospecifically to the 6β-position during biotransformation of cholesterol into cholestenone.