Issue 7, 1969

Triterpenoids. Part XXIX. Inter-relationship of cucurbitacin A with lanosterol

Abstract

Cucurbitacin A has been transformed into C(9)–C(10)–C(19) cyclopropane derivatives. By ring opening under anionic conditions the primary C(9)β-CH2OH group of cucurbitacin A has, in effect, been shifted and reduced to give a 10β-methyl group. A remarkable hydroxy-group participation in a carbanionic process is an essential element in the fission of the cyclopropane ring. By appropriate manipulation of the oxidation levels of the intermediates in this process, cucurbitacin A has been converted into 4,4,14α-trimethylpregn-8-ene-2,7,11,20-tetra-one, identical with authentic material prepared from the degradation of eburicoic acid. In this way the constitutions assigned to all the cucurbitacins have been confirmed. In addition, this work gives proof of the stereochemistry of the cucurbitacins at C-9, C-13, and C-14.

Article information

Article type
Paper

J. Chem. Soc. C, 1969, 1050-1056

Triterpenoids. Part XXIX. Inter-relationship of cucurbitacin A with lanosterol

D. H. R. Barton, C. F. Garbers, D. Giacopello, R. G. Harvey, J. Lessard and D. R. Taylor, J. Chem. Soc. C, 1969, 1050 DOI: 10.1039/J39690001050

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Spotlight

Advertisements