Anhydrobetulin and its derivatives

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Title:Anhydrobetulin and its derivatives
Creators:
Vystrčil, Alois
Křeček, Václav
Protiva, Jiří
Buděšínský, Miloš
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 56, 4, pp. 886-904

Abstract

The structure of anhydrobetulin <i>II</i> and its derivatives <i>I, III</i> and <i>IV</i> has been solved using <sup>1</sup>H and <sup>13</sup>C NMR spectra, mass spectra and chemical transformations. It has been proven that in addition reactions the trisubstituted double bond is attacked selectively from the α-side under formation of D/E <i>cis</i>-annelated derivatives <i>VIII, X</i> and <i>XI</i>. The 22-oxo derivative <i>XIII</i> exhibits an anomalous Cotton effect and, in contrast to its saturated analogue <i>XXVII</i>,it is not epimerized in alkaline medium. Trinordiketone <i>XXI</i> easily epimerizes to a mixture in which the 17βH-epimer <i>XXIb</i> predominates, trinorketone <i>XXIV</i> is stable only if the annelation of rings D and E is <i>trans</i>. These differences are explained in terms of steric interactions of substituents in position 19. The steric course of reduction of ketones <i>XIII</i> and <i>XXIV</i> with sodium borohydride is described.

Title:Anhydrobetulin and its derivatives
Creators:
Vystrčil, Alois
Křeček, Václav
Protiva, Jiří
Buděšínský, Miloš
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:56
Number:4
Page Range:pp. 886-904
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19910886UNSPECIFIED
ID Code:5006
Item Type:Article
Deposited On:22 Feb 2010 11:28
Last Modified:22 Feb 2010 10:28

Citation

Vystrčil, Alois; Křeček, Václav; Protiva, Jiří; Buděšínský, Miloš (1991) Anhydrobetulin and its derivatives. Collection of Czechoslovak Chemical Communications, 56 (4). pp. 886-904. ISSN 0010-0765

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