21,22-Disubstituted 18α,19βH-Ursane Derivatives with Oxabicyclooctane System in Ring E

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Title:21,22-Disubstituted 18α,19βH-Ursane Derivatives with Oxabicyclooctane System in Ring E
Creators:
Klinotová, Eva
Klinot, Jiří
Křeček, Václav
Buděšínský, Miloš
Máca, Bohumil
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 58, 1, pp. 173-190

Abstract

Reaction of 3β-acetoxy-21,22-dioxo-18α,19β<i>H</i>-ursan-28,20β-olide (<i>IIIa</i>) and 20β,28-epoxy-21,22-dioxo-19α,19β<i>H</i>-ursan-3β-yl acetate (<i>IIIb</i>) with diazomethane afforded derivatives <i>XII-XIV</i> with spiroepoxide group in position 21 or 22, which were further converted into hydroxy derivatives <i>XV</i> and <i>XVII</i>. Ethylene ketals <i>VIII-X</i> were also prepared. In connection with the determination of position and configuration of the functional groups at C(21) and C(22), the <sup>1</sup>H and <sup>13</sup>C NMR spectral data of the prepared compounds are discussed. Complete analysis of two four-spin systems in the <sup>1</sup>H NMR spectrum of bisethylenedioxy derivative <i>Xb</i> led to the proton-proton coupling constants from which the structure with two 1,4-dioxane rings condensed with ring E, and their conformation, was derived.

Title:21,22-Disubstituted 18α,19βH-Ursane Derivatives with Oxabicyclooctane System in Ring E
Creators:
Klinotová, Eva
Klinot, Jiří
Křeček, Václav
Buděšínský, Miloš
Máca, Bohumil
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:58
Number:1
Page Range:pp. 173-190
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc19930173UNSPECIFIED
ID Code:139
Item Type:Article
Deposited On:06 Feb 2009 16:58
Last Modified:06 Feb 2009 15:58

Citation

Klinotová, Eva; Klinot, Jiří; Křeček, Václav; Buděšínský, Miloš; Máca, Bohumil (1993) 21,22-Disubstituted 18α,19βH-Ursane Derivatives with Oxabicyclooctane System in Ring E. Collection of Czechoslovak Chemical Communications, 58 (1). pp. 173-190. ISSN 0010-0765

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