Macrolides absolute configuration

Searle PA, Molinski TF, Brzezinski LJ, Leahy JW (1996) Absolute Configuration of Phorboxazoles A and B from the Marine Sponge Phorbas sp. 1. Macrolide and Hemiketal Rings. J Am Chem Soc 118 9422... 

Purified DEBS 1-TE has also been used to investigate another interesting aspect of polyketide biosynthesis the control of stereochemistry. As noted by W. D. Celmer in 1965, the macrolide polyketides (the class of complex polyketide to which erythromycin belongs) have the same absolute configuration at all comparable stereocenters (Fig. 12) [40,41], These homologies suggest that there exists... 

Although the absolute configuration has only been established for a few polyene macrolide antibiotics, the search for new, efficient, and selective strategies for the synthesis of their polyol structures is in full swing. A number of the synthetic procedures presented here will certainly be used in future syntheses of this class of natural products [19]. 

Sasaki, K., Satake, M., and Yasumoto, T. 1997. Identification of the absolute configuration of pectenotoxin-6, a polyether macrolide compound, by NMR spectroscopic method using a chiral anisotropic reagent, phenylglycine methyl ester. 

Halichlorine (789) ([a]o +240.7°, c 0.54, MeOH), isolated from the Japanese sponge Halichondria okadai, is a complex alkaloid possessing a novel spiro-quinolizidine macrolide structure (537). Elucidation of the structure was based on detailed analysis of coupling constants and NOE effects in the NMR spectrum The absolute configuration of the ansa chain was inferred by degradation to the... 

Amphidinolide Q (16), C21H34O4, is a 12-membered macrolide possessing four branched methyl groups, an a ti-methylene, and a ketone carbonyl, isolated from the marine dinoflagellate Amphidinium sp. (strain Y-5). The relative stereochemistry of amphidinolide Q (l) was elucidated on the basis of -based configuration analysis method and NOESY correlations. The absolute configurations of amphidinolide (16) were concluded to he AR, 7R, 9S, 115, and 135 by application of the modified Mosher s method to amphidinolide 0 (16) and the linear methyl ester derivatives of amphidinolide... 

The structure and absolute configuration of maytansine (72 R = H) has been established by V-ray crystallographic analysis of its 3-bromopropyl ether [72 R = (CH2)3Br]. °° Maytansine represents the first ansa macrolide-type compound that shows in vivo tumour inhibitory properties. ... 

In recent years, much effort has been spent trying to determine the absolute configuration of the many polyene macrolide asymmetric centers, using well-established enantioselective organic transformations and advanced spectroscopic studies. This work is a necessary prelude to any accurate chemical modification, conformational analysis related to biological activity and, of course, attempt to totally synthesize a given antibiotic or analogue. 

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