Eburicoic acid

Poria cocos (Polyporaceae) (Syn. Sclerotium cocos) Fu Ling (fungus body) Pachymic acid, tumulosic acid, eburicoic acid, pinicolic acid, pachymarose.33 A diuretic, cardiotonic, it has tranquilizing effect, lower blood sugar levels, it is antibacterial and anticancer. 

Fried and co-workers at Squibb, in the process of degrading eburicoic acid (1) to 14-methylpregnane, converted the acid as acetate into the norketo acid (2) and... 

P. anthracophilus found on a Eucalyptus species were established at the same time. The work on eburicoic acid was carried out by Robertson in Liverpool. The elucidation of the structure of polyporenic acid A (5.161) benefited from experience gained in studies on the structure of lanosterol and on the penta-cyclic triterpenes. The identification of some structural features also showed the developing role of UV and IR spectroscopic methods in the 1950s. However, the purification of these compounds was impeded by the difficulty of separating the 8(9)-enes from the 7(8),9(ll)-dienes that often accompanied them. Initial studies on polyporenic acid A revealed the presence of a carboxylic acid, two hydroxyl groups and two double bonds, each of differing reactivity. One double bond was a terminal methylene since formaldehyde was obtained on ozonolysis whilst the other was more hindered. Typical of the tetracyclic triterpenes. 

Whilst this work was in progress comparable studies were carried out on eburicoic acid. In this case the relationship of the acid at C-21 to the alkene at C-24 was established by oxidation with Se02 to form a y-lactone (5.163). The size of the lactone ring was established by its IR absorption, correlations that at that time had only recently been established. The degradation of eburicoic acid linked it to lanosterol via a common hydrocarbon, a standard strategy in... 

In a new and convenient degradation of the side chain of eburicoic acid (1) to a methyl ketone group (5), the first step involved oxidative decarboxylation, using the procedure of Kochi (2, 235). The derived triene (2) was obtained in about 50% yield. Remaining steps involved anionic conjugation (3) ozonolysis... 

Le Blanc, G.D., and L.-M. Babineau 2,5-Dimethoxybenzoquinone, 3,4-Dimethyl-8-hydroxyisocoumarin, and Eburicoic Acid Isolated from Lenzites thermophila Falck-75. Canad. J. Microbiol. 18, 261 (1972). 

Eburicoic acid (Fig. 13), a steroid produced by certain types of fungi has been shown by Dauben and his co-workers (1956,1957 a, b) to possess a labeling pattern (after biosynthesis from acetate- C) that has many features in common with that of ergosterol. It is thus possible that eburicoic acid also arises from cyclization of squalene. 

Fifteen terpenoid antibiotics are included in this chapter two additional ones are discussed elsewhere in this book (mycelianamide and fumagiUin). All these substances contain carbon, hydrogen, and at least two oxygens. All are either monoterpenoids (comprised of two Cg units), sesquiterpenoids (three Cg units), or triterpenoids (six Cg units). Since most of the terpenoids are of these three types, this is hardly surprising a few diterpenoid (four Cg units) and carotenoid (eight Cg units) antibiotics will probably eventually be found. In some of the terpenoid antibiotics (e.g. grifohn and eburicoic acid), carbon atoms not derived from isopentenyl pyrophosphate (I) have become attached to terpenoid units in others (e.g. helvoHc acid and pristimerin), carbon atoms have been lost at some stage in the biosynthesis. 

Eburicoic acid (I) is one of the few terpenoids whose biosynthesis has been investigated with tracers. In a classic study, Dauben and Richards (1956) showed that eburicoic acid (I) incorporates acetate-1- C. By degrading the product, they determined that the labelhng pattern is one which would be expected for bio-... 

Eburicoic acid, T50 Eburna alkaloids, K16 Eburnamonine, K16 Eburnaphylline, K3 ... 

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