Cholesterol has been converted in a series of steps (a) into 14-methylcholestanol, identical with material obtained earlier from lanostenol, and (b) into lanostenol. By further processes the latter has been transformed into lanosterol (lanosta-8 : 24-dienol) and agnosterol [lanosta-7 : 9(11) : 24trienol]. These changes, coupled with the already known conversion of lanostenol into y-lanosterol [lanosta-7 : 9( 1 1)-dienol], represent total syntheses of all four wool-fat triterpenoids. THE triterpenoid fraction of wool fat consists of four alcohols : lanosterol (lanosta-8 : 24dienol) (I; R = H) and lanostenol (11; R = H, R' = C8H1,) which are present in major amount, and agnosterol [lanosta-7 : 9(11) : 24trienoll (111; R = H, R' = C8H1,) and y-lanosterol [lanosta-7 : 9(11)-dienol] (111; R = H, R' = C8H1,) which are present in minor am0unt.l The constitutions of these compounds have been established by degradation and by X-ray ~rystallography.~ The relative stereochemistry was also established in the latter investigations as well as by chemical * and biochemical considerations. The absolute stereochemistry, already proposed from molecular-rotation argumentsJs was also supported by these biochemical considerations. We now report (for preliminary communications see ref. 7) the conversion of cholesterol into all fourwool-fat triterpenoids. This work not only provides an unambiguous confirmation for all the conclusions summarised in the references cited above but, having regard to the total syntheses of cholesterol already effectedJ8 also constitutes a total synthesis of all four wool-fat triterpenoids.9We consider first the introduction of the gem.-dimethyl grouping into ring A of cholesterol (IV). Cholesterol can be readily converted through cholestd-en-3-one (V) and cholest-4-en-3-one (VIII) (for rapid and convenient procedures for the preparation of

Dr. T. F. Gallagher of the Sloan-Kettering Institute for Cancer Research (New York) has very kindly informed us that he has observed an analogous rearrangement in the steroid series.

Peat moss (Sphagnunt) from the surface of a n Atlantic peat bog has been extracted with a mixture of benzene and ethanol. The extract has been fractionated chromatographically 011 alumina. A mixture of sterols has been isolated from one fraction. 'This mixture has been proved by oxidation experiments to consist of 8-sitosta~lol (stigmastanol) and 8-sitosterol. I t constit~~ted approximately 0.2y0 by weight of the dried peat ~noss. INTRODUCTIONA considerable amount of work has been done on the chemical composition of peat (8), lignite (brown coal) (8)) and coal (8), but relatively little on the conlposition of peal: moss (Sphagnum). The latter is considered to be the main precursor of peat in the Atlantic area of Canada. This work was undertalien ill a n effort to remedy this defect, and also to ascertain what chemical changes occur in huinification. Black and his coworkers (4) carried out an extensive analysis on a sample of peat moss from Scotland and reported the presence of p-sitosterol.The peat moss used in our experiments was a living surface moss, from Shipigan, New Brunswick, ancl was essentially a mixture of Splzngnunz fuscum, S . capillacer~m, and S . magellanicum with the first two predominating. It was comparatively free of other common bog plants. T h e moss was clried to a moisture content of approximately 5% and ground to pass through a 20-mesh screen. Only relatively small quantities of the powder could be extracted a t a time, ouring to its bull;. The process used was a continuous extractioi~ method, with a constant stream of pure solvent passing through the moss.After evaporation of the solvent, the clarl; brourn guin (approximatell. 6% of the total solids) was saponified with methanolic potassiun~ hydroxide solution ancl the unsaponiliable material extractecl with ether. This extract (approximately 1.5% of the total solids), after evaporation, was dissolved in light petroleum and chromatographed roughly on alumina. A small portion of the gun1 (approximately 3%) did not dissolve in the petrol and was kept for further investigation. The eluate from the chromatogram was divided into five fractions: materials eluted progressively by ( a ) light petroleum, (b) benzene, (c) ether, (d) ether containing 10% ~nethanol, and (e) ~nethanol. These iractioils will be described separately. T h e coinposition of fractions (c) and (d) varied from extraction to extraction and with the grade of alumina used. The ether fraction so~netimes consisted of a white, low-melting solid, and the ether-methanol fraction of a colorless crystalline solicl, subsequently proved t o be the sterols. In the majority of extractions, however, the con~ponents were c nixed and tended to be removed fro~n the column together in fraction (d) as a light yellow glass. T h e ~nixture was separated into cyclic and linear aliphatic compounds by treatment with urea with which the latter formed an insoluble complex. Decompositio~l of the complex yielded an alcohol which has been tentativel!. identified as lignoceryl alcohol by meltin...

By further chromatographic fractionation of the unsaponifiable matter from an extract of peat moss (Sphagnunz) three crystalline triterpenes have been isolated. They have been identified as a-amyrin, taraxerone, and taraxerol by their physical and chemical properties.In the preceding paper (5) the method of separating the crude unsaponifiable material present in peat moss was described. Two sterols were isolated and identified. This paper deals with some of the other compounds isolated during the chromatography of the crude extract. The fraction of unsaponifiable material eluted from the alumina column with benzene represented approximately five per cent of the total. This material consisted of a light yellow oil which crystallized on standing. Attempts to purify it by crystallization from methanol or ethanol failed. However, if the material was taken up in light petroleum, a yellow sirup was dissolved leaving a white crystalline mass, which after filtration could be readily recrystallized from chloroform-methanol solution. T h e crystals melted a t 238'-239' and had a specific rotation of f12". The material gave a crystalline derivative with 2,4-dinitropheny1h)rdrazine and showed a marked peak in the infrared a t 1705 cm.-I, indicative of a carbonyl group. The infrared spectrum of this ketone from peat moss also showed the presence of a double bond by a band a t 816 cm.-l and the position of the band indicated a trisubstituted double bond in a six-membered ring. The high melting point and comparatively few functional groups, in addition to a positive Liebermann-Burchard reaction, indicated that the compound could be a triterpene, possibly of the allobetulin series. This hypothesis was reached since derivatives of allobetulin have been found in lignite (8), a decomposition product of peat. However, analysis showed the presence of only one oxygen function, the carbonyl group, whereas allobetulin itself has two, one being an ether function. A search of the literature showed that the lietone was possibly taraxerone (I), previously isolated from Tara.xacum oficinale (3) and Aln7rs glz~ti~zosa L. ( I ) , and further chemical evidence confirmed this. The Icetone was reduced with lithium aluminum hydride to give the alcohol (11, R = H ) , which had the physical constants of taraxerol. This was confirmed by the preparation of the acetate in the usual way (11, I< = Ac). This acetate was treated with hydrochloric acid in acetic acid ( I ) and the resulting product crystallized from chlorofornl-methanol to give 0-amyrin acetate (111, R = Ac), identified by melting and rotation and the melting point and rotation of the derived alcohol (111, I< = H) 0-amyrin. This rearrangement has been shown to involve the migratio~l of a methyl group from C13 to C1.l with the concomitant movement of the double bond from the 14,15-position to the 12,13-position. The process is concerted and there are no intermediates. I t is also irreversible and the yield of P-amprin is virtually 100%. The rearrangement is typical of taraxerol and ...

No abstract