By R. Bangert, J. Bonner, H. Brockmann, L. Crombie, L. Jaenicke, C. Kutzbach, A.D. Mebane, H. Muxfeldt, W. Oroshnik
In the course of the early 1950's there seemed stories, now and then of the presence one of the items elaborated by means of actinomycetes of antifungal antibiotics which exhibited very related and extremely attribute multipeaked ultraviolet absorption spectra. In 1954, with lots of examples on list, those spectra have been analyzed and pointed out as these of straight-chain conjugated polyenes, comprising tetraenes, pentaenes, hexaenes and heptaenes (85, I30). those antibiotics have because been in most cases known as the polyene antifungal antibiotics to tell apart them from a bunch of different miscellaneous antibiotics which even have antifungal houses. in the following couple of years, studies of discoveries of recent contributors of this type improved swiftly, and nearly sixty at the moment are recognized. absolutely, a few those will finally be came upon to be exact with others, as has already occurred in different cases: for instance, the tetraene "tennecetin" proved to be a rediscovery of pimaricin (34), and within the methyl- pentaenes "moldcidin E" has been pointed out with pentamycin (83), and "lagosin" seems to be indistinguishable from fungichromin (22). those who were purified have became out to be of particularly excessive molecular weight (ca. 700-1300) and all seem to be components of really comparable molecular constitution. to date in simple terms 3, pimaricin, fungi- chromin (lagosin) and filipin, were structurally elucidated.
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Additional info for Progress in the Chemistry of Organic Natural Products/Progres Dans La Chimie Des Substances Organiques Naturelles
G. by spontaneous air oxidation of a concentrated alcoholic solution (I34)], a reaction which was not noted for fungichromin or "lagosin"*. This difference was confirmed when filipin was found to contain no vicinal glycol group (no reaction with periodic acid) until after saponification of the lactone, which unmasked a glycol that consumed periodic acid with production of acetaldehyde and a pentaenal of Amax 386 mfl (IJ)· Since the filipin carbon chain could not be broken beyond the chromophore by periodic acid, a less selective reaction, nitric-acid oxidation, had to be resorted to: by this degradation, perhydrofilipin gave a mixture of acids whose largest identifiable member (by gas chromatography of the methyl esters) was iX-methyldodecanedioic acid (XV).
C=o (IlL) 13-Hydroxytetradecapentaenal. Chart 2. Alkaline Cleavage of Pimaricin. It will be observed that this single reaction, as formulated in Chart 2, involves no less than seventeen carbon atoms-half of the total number present in pimaricin. That the lactone ring does actually extend to the position shown, enclosing the entire polyene chain, would of course not be established by this reaction alone; in fact, no coercive evidence on this point was presented by the Lederle workers (89). However, there can be no doubt that PATRICK'S placement of the chromophore inside the lactone ring is correct, in the light of the complete structural solutions independently arrived at by the research teams of COPE (M.
Thus, the entire carbon skeleton was conclusively verified from this single derivative. ) 7,2I·Dimethyltritriacontane. CHa I HOCH2-CH-(CH2)9-CH-CH-CHa I I OH OH (XL) To locate the oxygen atoms, periodic acid fission (in this case, of perhydrofungichromin) was again resorted to. Lithium aluminum hydride reduction then gave two crystalline polyols, C19H400S and C15Ha20a, which could be deoxygenated to hydrocarbons identifiable by transpose mass spectrum as C6-C(CHa)-Cn and C-C(CHa)-C12. The eight hydroxyls of the C19-polyol could be located unambiguously on its carbon skeleton by the same two criteria previously mentioned, i.