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19β,28-Ep-oxy-18α-olean-3β-ol.

ABSTRACT: The title triterpene, C(30)H(50)O(2), is an 18α-oleanane derivative prepared by the Wagner-Meerwein rearrangement of betulin with Bi(OTf)(3).xH(2)O (OTF is trifluoromethanesulfonate). There are two symmetry-independent mol-ecules in the asymmetric unit that show no significant differences concerning bond lengths and angles. The conformation of the six-membered rings is close to a chair form, while the five-membered epoxide rings adopt envelope conformations. All rings are trans-fused. In the crystal, mol-ecules are held together by O-H⋯O hydrogen bonds. A quantum-mechanical ab initio Roothan Hartree-Fock calculation on the isolated mol-ecule gives values for bond lengths and valency angles close to the experimental values. The calculations also reproduce well the mol-ecular conformation with calculated puckering parameters that match well the observed values.

SUBMITTER: Santos RC

PROVIDER: S-EPMC2969885 | biostudies-literature | 2009 Aug

REPOSITORIES: biostudies-literature

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19β,28-Ep-oxy-18α-olean-3β-ol.

Santos R C RC Pinto R M A RM Matos Beja A A Salvador J A R JA Paixão J A JA

Acta crystallographica. Section E, Structure reports online 20090808 Pt 9

The title triterpene, C(30)H(50)O(2), is an 18α-oleanane derivative prepared by the Wagner-Meerwein rearrangement of betulin with Bi(OTf)(3).xH(2)O (OTF is trifluoromethanesulfonate). There are two symmetry-independent mol-ecules in the asymmetric unit that show no significant differences concerning bond lengths and angles. The conformation of the six-membered rings is close to a chair form, while the five-membered epoxide rings adopt envelope conformations. All rings are trans-fused. In the cry ...[more]

PMID: 21577506

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