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The NMR spectroscopy technique is employed to analyze the direct interaction taking place between amphotericin B (AmB) and ergosterol in lipid bilayers. The results prove the existence of a direct intermolecular interaction between the two components in the bilayers.

A convergent method to construct the 6/7/6/6-tetracyclic ether system possessing contiguous angular methyl groups was developed. The key steps of the synthesis involve coupling of a lithium acetylide and an aldehyde, cyclodehydration of a hydroxy ketone to form a dihydropyran, ring expansion of a six-membered ring ketone into a seven-membered one, and methylation of a mixed-thioacetal. Based on this strategy, syntheses of the WXYZ ring of maitotoxin and the HIJK ring of brevisulcenal-F were achieved, and the stereochemistry of the HIJK ring of brevisulcenal-F was confirmed. [ABSTRACT FROM AUTHOR]

The diversity-oriented doubling strategy, which generates two 12-arylbenzoacridines from a single triarylmethanol precursor was developed to construct a library of drug candidates for the identification of biologically active compounds. Exploration of this 12-arylbenzoacridine library furnished a 4'-OH derivative as an estrogenic compound. [ABSTRACT FROM AUTHOR]

2-Naphthylmethoxymethyl (NAPOM) was developed for the protection of various hydroxy (including phenolic hydroxy and carboxy) and mercapto groups. The NAPOM group can be introduced in extremely mild conditions (naphthylmethoxymethyl chloride, 2,6-lutidine, room temperature) without concomitant acyl migration in a 1,2-diol system. Furthermore, selective removal of NAPOM in the presence of naphthylmethyl (NAP) and p-methoxybenzyl (PMB) groups and, conversely, that of PMB in the presence of NAPOM were realized. These results, as well as its easy handling and compatibility with various solvents, show that NAPOM is a novel and useful choice as a protecting group. [ABSTRACT FROM AUTHOR]

The WXYZA′B′C′ ring system ( 1) of maitotoxin (MTX) was synthesized in a convergent manner via successive coupling of the W, Z, and C′ ring fragments through construction of the XY and A′B′ ring systems. The synthetic segment 1blocked the hemolytic activity elicited by MTX. [ABSTRACT FROM AUTHOR]

Maitotoxin (MTX) is a ladder-shaped polyether produced by an epiphytic dinoflagellate. As a part of our structureactivity relationship studies using synthetic partial structures of MTX, the QRS ring comprising a 6/6/7 tricyclic system was synthesized through stereoselective construction of five contiguous stereogenic centers on the Q ring via i) coupling of a Weinreb amide and a furyllithium, followed by ii) Noyori asymmetric transfer hydrogenation, iii) the Achmatowicz reaction, iv) chemoselective methylation of a methyl acetal in the presence of a carbonyl group by treatment with Me2Zn/BF3*OEt2, v) highly diastereoselective dihydroxylation, and vi) ring expansion of a six-membered to a seven-membered ring ketone. The synthetic specimen inhibited MTX-induced Ca2+ influx with an IC50 value of 44 μM. [ABSTRACT FROM AUTHOR]