Of aureol

Because the isotopic composition of igneous rocks is quite different from those of sedimentary rocks, studies of the isotope variations in the vicinity of an intrusive contact offer the possibihty of investigating the role of fluids interacting with rocks around cooling plutons. Two types of aureole can be distinguished (Nabelek 1991)... 

A further natural product inhibitor is mithramydn A, a structurally complex anticancer antibiotic. Mithramycin A is a member of a group of aureolic add-type polyketides that are produced by the soil bacterium Streptomyces argillaceus [94]. 

J. Thiem and M. Gerken, Synthesis of the E-D-C trisaccharide unit of aureolic acid cytostatics, J. Org. Chem., 50 (1985) 954-958 and references therein. 

J. Rohr, C. Mendez, and J. A. Salas, The biosynthesis of aureolic acid group antibiotic, Bioorg. Chem., 27 (1998) 41-54. 

Iodo-glycosides can be a valuable alternative to the above-mentioned 2-bromo derivatives. Easily prepared via addition reactions to glycals of NIS or I(coIl)2C104 and alcohols [30,157], these donors were successfully used in the synthesis of aureolic acid oligosaccharides [155,156,158]. 

As reviewed in an earlier volume in this series (110) the absolute stereochemistry attributed to ilimaquinone [75] on the basis of circular dichroism measurements was incorrect. The correct absolute stereochemistry for ilimaquinone was ultimately established by degradative correlation to aureol [49]. The absolute stereochemistry of aureol had been determined via X-ray analysis of a monobromo derivative. This stereochemical reassignment to ilimaquinone was important for reasons other than simply establishing the correct stereostructure for this particular marine metabolite. Ilimaquinone is a common co-metabolite in sponges that in turn have been the source of a variety of new sesquiterpene/quinones. Frequently these new compounds have been attributed the same "absolute stereochemistry" as ilimaquinone [75], principally on the basis of biosynthetic considerations. 

Roush WR, Briner K, Kesler BS, Murphy M, Gustin DJ (1996) Studies on the synthesis of aureolic acid antibiotics acyloin glycosidation studies. J Org Chem 61 6098-6099... 

Franck RW, Kaila N (1993) Synthesis of C D disaccharide of aureolic acid. Carbohydr Res 239 71-83... 

The glycal derivative (9), on heating with the cyclobutane (10), gave the adduct (11) (Scheme 6) which was used to prepare a model of the aglycone of aureolic acid (Chapter 23). 

Given their high pressure II, monolayers are rather rigid. As such, they can transmit acoustic signals (shock waves) at velocities superior to V. This translates into the appearance of aureoles around the hole, as discussed by Mysels and Frankel. On the whole, the dynamics of rupture is relatively clear for thick films (one micron or more). It is much more complex for thin films, where surfactant effects become predominant. 

Aureolic acid, an antibiotic with antitumour activity isolated from a Strepto-myces species, has been shown to be identical with mithramycin [368, 369]. Acid hydrolysis of the compound has afforded [370] the aglycone chromo-mycinone (LXXVIIIb) and the sugars mycarose (LXXIXa), chromose C (LXXIXd), and oliose (LXXIXb). The points of attachment and sequence of the sugar chains, and the chirality of aureolic acid (LXXVIIIc) have been... 

Methods available for the synthesis of deoxyoligosaccharides found as parts of antibiotics and cytostatics have been described and illustrated for four different trisaccharides of aureolic acids. ... 

Roush WR, Lin X-F. Studies on the synthesis of aureolic acid antibiotics highly stereoselective synthesis of aryl 2-deoxy-p-glycosides via the Mitsunobu reaction and synthesis of the olivomycin A-B disaccharide. J. Am. Chem. Soc. 1995 117 2236 2250. 

Nakamura, M., Suzuki, A., Nakatani, M., Fuchikami, T Inoue, M., and Katoh, T. (2002) An efficient synthesis of (+)-aureol via boron trifluoride etherate-promoted rearrangement of (+)-arenarol. Tetrahedron Lett., 43, 6929-6932. 

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