492. The chemistry of fungi. Part XIX. The structure of eburicoic acid

Abstract

The Chemistry of Fungi. Part X I X .

Optical Rotatory Dispersion Studies. XVII.1 Detection of Conformational Alterations. Effects of Alkyl Groups and Double Bonds in Polycyclic Systems2

“…ularly suitable examples for a more detailed examination of this effect are available in the steroid (49) A. Bowers, T, G. Halsall, E. R. H. Jones and A, J. Lemin, Chem. Soc., 2548(1953.…”

The Structure of the Cactus Sterol Macdougallin (14α-Methyl-Δ8 -cholestene-3β,6α-diol). A Novel Link in Sterol Biogenesis1,2

“…The combination of a 14a-methyl substituent and an 8(9)-double bond is a characteristic of many tetracyclic triterpenes such as lanosterol and eburicoic acid18 (VII), which can readily be isomerized to an equilibrium mixture of 7(8)-and 8(9)-enes on treatment with hydrogen chloride in acetic acid. 18 Under these conditions, macdougallin diacetate was recovered largely unchanged, but a very small amount of a less polar compound was detected by thin layer chromatography. This material was isolated by column chromatography on alumina, and the recovered starting material then was retreated with hydrogen chloride in acetic acid.…”

Studies in Phytosterol Biosynthesis: Observations on the Biosynthesis of Fucosterol in the Marine Brown Alga Fucus spiralis

“…On the basis of the gas-liquid chromatography data steryl acetate 1 is tentatively assigned the structure 3p-acetoxy-stigmasta-5,23,-diene. This structure gains support from observation [18,19] [24] and into B-sitosterol by peas [25] gave 3H/14C atomic ratios of 315 thus demonstrating that the tritium originally a t C-24 is the phytosterol precursor is retained during alkylation. However, this work provided no evidence with regard to the location of the tritium.…”