Synthesis and in vitro antifungal activities of novel triazole antifungal agent CS-758.

Synthesis and in vitro antifungal activities of a novel triazole antifungal agent CS-758 (former name, R-120758) are described. The minimum inhibitory concentrations (MICs) of a series of dioxane-triazole compounds related to R-102557 were examined. Variation of the length of the chain between the dioxane ring and the phenyl ring revealed that the linkage with two double bonds is the most preferable. When a cyano group was introduced to the C4 position on the benzene ring, MICs improved further. A fluorine atom was introduced to obtain CS-758. The MICs of CS-758 surpassed those of fluconazole and itraconazole against Candida, Aspergillus and Cryptococcus species. The precursor (E,E)-aldehyde was synthesized stereoselectively from 3-fluoro-4-methylbenzonitrile using the Horner-Wadsworth-Emmons reaction.     

Synthesis of Chiral Crownophanes Having Two Phenolic Groups via Tandem Claisen Rearrangement and Their Chiral Recognition

Asymmetric crownophanes having a chiral binaphthyl unit and two phenolic hydroxyl groups were thermally synthesized from the corresponding macrocyclic ethers via tandem Claisen rearrangement. Circular dichroism (CD) spectroscopic studies and HPLC experiments confirmed that little racemization of these crownophanes occurred during the thermal rearrangement. The association constants for the interaction of the chiral crownophanes with the enantiomers of phenylethylamine, phenylglycinol, and phenylalaninol were determined by a ¹H NMR titration method in CD₂Cl₂. As a result, the 27 membered crownophane has some chiral recognition for phenylglycinol.     

Statistical behavior of post-shock overpressure past grid turbulence

When a shock wave ejected from the exit of a 5.4-mm inner diameter, stainless steel tube propagated through grid turbulence across a distance of 215 mm, which is 5–15 times larger than its integral length scale \(L_{u}\) , and was normally incident onto a flat surface; the peak value of post-shock overpressure, \(\Delta P_{\mathrm{peak}}\) , at a shock Mach number of 1.0009 on the flat surface experienced a standard deviation of up to about 9 % of its ensemble average. This value was more than 40 times larger than the dynamic pressure fluctuation corresponding to the maximum value of the root-mean-square velocity fluctuation, \(u^{\prime }= 1.2~\hbox {m}/\hbox {s}\) . By varying \(u^{\prime }\) and \(L_{u}\) , the statistical behavior of \(\Delta P_{\mathrm{peak}}\) was obtained after at least 500 runs were performed for each condition. The standard deviation of \(\Delta P_{\mathrm{peak}}\) due to the turbulence was almost proportional to \(u^{{\prime }}\) . Although the overpressure modulations at two points 200 mm apart were independent of each other, we observed a weak positive correlation between the peak overpressure difference and the relative arrival time difference.     

Synthesis and antifungal activities of R-102557 and related dioxane-triazole derivatives

Novel triazole compounds with a dioxane ring were synthesized. Condensation of the diol precursor 10 with various aromatic aldehydes 11-13 under acidic conditions afforded a series of dioxane-triazole compounds 14-16. The antifungal activities of the compounds 14-16 were evaluated in vivo in mice infection models against Candida and Aspergillus species. High activities were seen for the derivatives with one or two double bond(s) and an aromatic ring substituted with an electron-withdrawing group in the side chain. Among the derivatives, R-102557 (16R: Ar=4-(2,2,3,3-tetrafluoropropoxy)phenyl) showed excellent in vivo activities against Candida, Aspergillus and Cryptococcus species. It also showed high tolerance in a preliminary toxicity study in rats.     

Synthesis and structure of macrocyclic bis(hydroxynaphthoic amide)s connected by an achiral or chiral diamine

Macrocyclic bis(hydroxynaphthoic amide)s 6, connected by an achiral or chiral diamine, were synthesized by the tandem Claisen rearrangement. CD spectra, X-ray crystallographic analyses, and variable-temperature NMR measurements of the chiral bis(hydroxynaphthoic amide)s revealed that the two hydroxynaphthalene rings in these macrocycles adopt a twisted conformation both in solution and in the crystalline state because of the steric hindrance between the two hydroxynaphthalene rings and that the chirality of the twisted conformation is generated by that of the chiral linker. Theoretical calculations revealed that the chiral linker works effectively to favor energetically one conformer of the diastereomers, although a flipping process was possible and can be observed to occur on the NMR time scale in variable-temperature experiments.