No abstract

Three hydroxy-ketones and two hydroxy-diketones have been isolated irom the triterpene mixture from Siphoizodon australe Benth. These compounds have been related to the ketones described in Part I and, where possible, configurations have been assigned to the hydroxyl groups. The five compounds can consequently be named x[eq]-and x[ax]-hydroxyfriedelan-3-one, y-hydroxyfriedelan-3-one, x[eqj-hydroxyfriedelane-3 : y-dione, and y-hydroxy-Reduction of friedelan-x-one by two different methods gives two epimeric alcohols, but reduction of friedelan-y-one by the same two methods gives only one alcohol.Molecular-rotation differences observed with these compounds support the absolute configuration assigned to friedelane.1 This configuration is a partial " skeletal enantiomorph " of the 5a-steroids and the usual triterpenes; consequently reduction of 3-oxo-derivatives with sodium borohydride yields mainly axial (SP-)alcohols. THREE hydroxy-ketones and two hydroxy-diketones have been isolated from the triterpene mixture from Siphonodon austvale Benth. and, as described in the sequel, have been related (a) Corey and Ursprung, J . Anzev. Cheuz. Soc., 1955, 77, 3667, 3668 : (b) Brownlie, Spring, Stevenson, and Strachan, Chem. aizd Ind.* If bonds at corresponding carbon atoms in the two " skeletal enantiomorphs " are to have the same orientation (a or p) they must necessarily have different configurations (axial or equatorial).Orientation, in the sense used here, does not necessarily have any absolute significance but is defined by the direction of the exocyclic bond at C(,,, which is a in the friedelane series and fl in the series represented by structures (11) and (111).

The seed fat of the Kerguelen cabbage, an isolated member of the Cruciferae, has been analysed. The fatty acids have been found to include erucic acid as a major component (13.5%). cis‐II‐Eicosenoic acid is also present in approximately equal amount (13.8%), together with linolenic acid (30.3%) and linoleic acid (20.1%). Other acids are present in smaller amounts. Analysis of the fat has been made by ester distillation and also by amplified distillation of the methyl esters of the saturated acids and of the hydrogenated acids. The merits of the two methods are compared. The oxidation of the monoenoic acids to dihydroxy‐acids with performic acid is a convenient method for their characterization.

threo-9,10-Dihydroxyoctadecanoic acid (I) like its erythro-isomer gives good yields of 2-hydroxy-2-octyldeoandioic acid (II) when fused with alkali. Under similar conditions 9,lO-diketo-octadecanoic acid gives a somewhat lower yield of this same acid and is considered a probable intermediate in the conversion of I to II. Esters of II have been tested as lubricants at low temperatures and as plasticizers. They are too heat sensitive to serve as lubricants. The octyl side chain renders them less effective as plasticizers than esters of sebacic acid. The 2-ethylhexyl ester of 2-octyldecandioic acid (III), derived from II, has properties which fit it for use as a lubricant.

The large seeds of Omphalea queetislandiae, a member of the Euphorbiaceae, contain 28% of an edible, semi-drying oil. Its component glycerides consist almost entirely of those of the four common fatty acids, which in one sample were present in the proportions : palmitic 12'7, stearic 8.1, oleic 47.0 and liiioleic 31.746. The composition of the oil is variable.