Studies in triterpenoids and steroids

Shaw, James I (1957) Studies in triterpenoids and steroids. PhD thesis, University of Glasgow.

Abstract

An Examination of the steroidal sapogenin content of sisal juice resulted in the isolation of three known sapogenins, neotigogenin, neohecogonin (sisalagenin) and hecogenin, and a compound of unknown structure, compound S acetake. Compound S acetate on Wolff-Kishner reduction gave tigogenin acetate, indicating that compound S acetate is a ketotigogenin acetate. Unsuccessful attempts were made to determine the position of the carbonyl group. Bromo- and A-Chlorocholest-A-en-3-one An unambiguous method of preparation of 4-bromo-and 4-chloro-cholost-4-en-3-one has been found. This comprised in treatment of 4p:5-epoxycoprostan-3-one with hydrobromic or hydrochloric acid. The ultra-violet absorption characteristics of these compounds and derivatives were examined. q-Amyrln Experiments leading to a new stereoformula for alpha-amyrin are described including the conversion of a simple ursane derivative to an olearane derivative. With the nature of ring E still in doubt, experiments with the object of introducing- reactive groupings in ring E were carried out in order to obtain some direct evidence to the nature of this ring. A thorough examination of the oxidation of ursa-9(H)s 12-dien-3beta-yl acetate was made, four neutral compounds being isolated and identified. The first recorded preparation of an ursane derivative with a double bond in ring E is described. Four compounds with an 18-19 double bond were obtained, these are, ursa-9(11): 12:18-trien-3beta-yl acetate, 3beta:12-diacetoxyursa-9(11): 12:18-triene, 12-oxouraa-9(11):18-dien-3betayl acetate, and 12-oxours-18-dien-3beta-yl acetate. A discussion of the merits of the two principal stereoformulae for alpha-amyrin (i.e. the six-membered ring E, and the five-membered ring E) is given.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Additional Information: Adviser: F S Spring
• Keywords: Organic chemistry
• Date of Award: 1957
• Depositing User: Enlighten Team
• Unique ID: glathesis:1957-73561
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 14 Jun 2019 08:56
• Last Modified: 14 Jun 2019 08:56
• URI: https://theses.gla.ac.uk/id/eprint/73561