Zur Kenntnis der Triterpene. (87. Mitteilung). Über verschiedene Umwandlungsprodukte des Lanosterins

Abstract

In friiheren Mitteilungen dieser Reihe haben mir3) uber Umwandlungsprodukte der zweifach ungesiittigten tetracyclischen Elemiharzsauren C,,H,,O, berichtet und dabei verschiedentlich auf experimentelles Material hingewiesen, wonach sich eine auff allende Parallele im chernischen Verhalten dieser Triterpensiiuren einerseits, und der gleichfalls doppelt ungesattigten tetracyclischen Triterpenalkohole C,,H,,O Lanosterin4) und Kryptosterin5) andersejts ergibt. Zur genaueren Verfolgung dieser Zusammenhange hatten wir die Bearbeitung der beiden Alkohole aufgenommen. Ferner haben vor kurzer Zeit Wieland ~m d Belzertde), sowie Wielalzd und Joost7) die Resultate ihrer Arbeiten uber Lanosterin und Hryptosterin veroffentlicht, die teilweise von den von uns erhaltenen Ergebnissen abweichen, so dass wir zu einer vergleichenden Erorterung des bearbeiteten Gebietes veranlass t sind.Die Reindarstellung des Lanosterins aus dem Wollfett der Schafe bietet grosse Hindernisse, obwohl die in der Literstur enthaltenden Arbeitsvorschriftens) diese Operationallerdings in Unkenntnis der wirklich vorliegenden, weiter unten geschilderten Schwierigkeitenals eine relativ einfsche Aufgabe hinstellen. Fur unsere Versuche stellten wir uns einen Acetonextrakt aus Clem Cnrerseifbaren des Wollfettes her. Die darin enthaltenen Fettalkohole lassen sich mit Hilfe der chromatographischen Trennungsmethode Tollstiindiger entfernen als durch Auskochen mit Benzing), wonach das auf diese Weise vorgereinigte Alkoholgemisch durch oftmaliges Auskochen mit Netha-no1 leicht von Cholesterin befreit werden kannlO). Gnsere zahlreichen I) 86. Mitt. Helv. 27, 183 (1944): 2) Vgl. A. C. Illuhr, Vber die triterpenartigen Bestandteile des Wollfettes, Diss.

The Chemistry of the Triterpenes

“…(66). Finally a relationship is suspected be tween agnosterol, cryptosterol, and lanosterol and the elemi acids (67). It is still too early to decide whether quinovic acid is a representative of still another type of carbon skeleton (117,118).…”

“…Moreover, the principal product of dehydro genation with selenium is 1,2,8-trimethylphenanthrene (116,67) as is the case with a-e1emolic acid (109), and analogous compounds are obtained by chromic anhydride oxidation of dihydro-a-elemolic acid and dihydrocryptosterol (109, 11S). Attempts, however, to relate the NOLLER two groups of compounds more closely by comparing hydrocarbons derived from them have not been successful (67). In view of the demonstrated nonrelationship to the sterols, it would seem to be ad visable to change the names of lanosterol, agnosterol, and cry p tosterol, possibly to lanol, agnol, and cryptol.…”

“…Not only are they tetracyclic with one double bond that can be hydro genated by catalytic reduction, but this double bond is present in an isopropylidene group since ozonolysis of lanosterol or cryptosterol gives acetone (22,67). Moreover, the principal product of dehydro genation with selenium is 1,2,8-trimethylphenanthrene (116,67) as is the case with a-e1emolic acid (109), and analogous compounds are obtained by chromic anhydride oxidation of dihydro-a-elemolic acid and dihydrocryptosterol (109, 11S). Attempts, however, to relate the NOLLER two groups of compounds more closely by comparing hydrocarbons derived from them have not been successful (67).…”

Detection and quantification of lanosterol and dihydrolanosterol esters by measurements of metastable decompositions. Application to their direct analysis in wool wax

“…Estimated rangea Fatty acid in 10 probably due mainly to the loss of a 4-methyl group, and the elimination of a fatty acid molecule from the 3-position of this ion would proceed by a different and much slower process than the normal elimination pathway from a secondary ester group. The specificity of this metastable transition probably precluded the interference of compounds possessing different methylated or alkylated sterol nuclei (on positions other than 2 or 4), or of oxygenated sterols which could give rise to isobaric ions.…”

Assay of the possible organization of particle-bound enzymes with squalene synthetase and squalene oxidocyclase systems

“…It is known that the chromic acid oxidation of 24,25dihydrolanosteryl acetate (Va) (Scheme 3) leads to a mixture of compounds, in which compounds (VI) and (VII) (Scheme 3) have been recognized (Ruzicka, Rey & Muhr, 1944). If, during this oxidation of dihydrolanosteryl acetate, there is no exchange of protons at C-12 with the acetic acid medium, this molecule could be used for our purposes, for it is then sufficient to oxidize the labelled compound with chromic acid and to isolate compound (VI).…”