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Decarboxylative arylation of α,α-difluoro-β-ketoacid salts with diaryliodonium(III) salts has been developed to synthesize α-aryl-α,α-difluoromethyl ketones, which are attractive synthetic intermediates for various difluorobenzyl units. This additive-free arylation represents an alternative approach to conventional synthetic methods that rely on transition metal catalysts and/or organometallic compounds. The reaction involves sequential ligand exchange of difluoroketoacid with tosylate ligand of diaryliodonium salt, followed by decarboxylative ligand coupling. Various functional groups, including ester, nitro, cyano, heteroarenes, and aryl halide groups, were tolerated during the present reaction. The resulting α-aryl-α,α-difluoromethyl ketones can be transformed into the corresponding esters, amides, and difluoromethyl compounds, which are commonly found in biologically active compounds.

We determined the fifteen types of plasticizers, including four kinds of phthalic acid esters (PAEs) used in 220 polyvinyl chloride (PVC) toys on Japanese market from 2019 to 2020. Three kinds of previously undetected types of PAEs were also detected, but not identified in this study. Di (2-ethylhexyl) terephthalate (DEHTP) was the highest detection rate in 209 soft PVC toys out of 220 toys, with 71.2% for designated toys and 88.9% for not-designated toys, respectively, showing a gradual increase from the previous reports in 2009 and 2014. On the other hand, the usages of o-acetyl tributyl citrate and adipic acid esters decreased, but the six types of PAEs prohibited to use for the designated toys in Japan were not detected in them, the usage of diisobutyl phthalate were increased. In contrast, four types of PAEs were detected in not-designated toys. Among them, the detection ratio of di (2-ethyhexyl) phthalate decreased to about 1/10. The content levels of plasticizers in per each sample were continued to keep low level from the report five years ago. These results showed that the main plasticizer used in PVC toys is DEHTP, and that the usage of other plasticizers was decreased.

Three esters of Hinoki cypress (Chamaecyparis obtusa)-lignophenol(p-cresoI type, HCLC), acetate (HCLCAc), benzoate (HCLCPh) and oxyallylcarbonate (HCLCalloc), were investigated using FT-1R, ¹H NMR, SEC, TGA, TMA and DSC. These esters demonstrated larger MW than lignophenol (LP) due to electrostatic interaction and inter- and intra-molecular interactions of ester side chains. Both TGA and TMA showed higher thermal stability and good plasticity at a lower temperature than HCLC. The thermal stability of esters were evaluated using Ozawa plots of the TGA analysis data. Improvement of these properties depends on both ester linkages and side chains of esters. Moreover, DSC showed clear Tg on the first run without exo-thermal peaks, that means no thermal degradation. These results show that it is possible to control the properties of lignophenol esters and to investigate unknown thermal properties of main chains in HCLC based on native lignin. [ABSTRACT FROM AUTHOR]

Reversible addition fragmentation chain transfer (RAFT) agents were obtained from condensed reactions between dithiobenzoic acid 4-(4-cyanopentanoic acid) ester (RAFT-A) and dinitrophenyl-polyoxyethylene (DNP-PEG). Mono-dispersed polystyrene particles containing dinitrophenyl groups have been prepared by RAFT polymerization. In the result, 2.1 ~ 2.3 µm polystyrene particles with contents of 1.2 ~ 2.6 wt% DNP corresponding to PEG molecular weight were obtained. The polystyrene particles interact with anti DNP antibodies in the dispersion solution and caused the immuno-aggregation of polystyrene particles. Also, this immuno-aggregation behavior occurred for 2,4-DNP specificity. [ABSTRACT FROM AUTHOR]

This review focuses on a new solid-phase synthetic strategy for an anticancer natural product yaku'amide B (1) and its target identification and structure-function relationship study using synthetic analogues and probes. To realize the Fmoc-based solid-phase synthesis of 1, we developed new synthetic methods for enamide formation. Namely, modified traceless Staudinger ligation using alkenyl azides and newly designed phosphinophenol esters enabled stereoselective construction of the (E)- and (Z)-ΔIle moieties. Furthermore, resin-cleavage and C-terminus modification were simultaneously achieved with an ester-amide exchange reaction using C-terminal amine and AlMe 3 , which successfully afforded 1 via a full solid-phase route. The developed strategy was applied to the construction of seven E/Z isomers of 1. In the target identification of 1, fluorescent imaging study and affinity pull-down assay using the synthetic probes revealed that 1 exerts potent cytostatic activity by binding to subunits α and β of mitochondrial F o F 1 -ATP synthase. On the basis of the mode of action of 1, we conducted biological evaluation of the seven E/Z-isomers of 1. Assessment of growth inhibition activity and the effect on F o F 1 -ATP synthase indicates that the E/Z-stereochemistry of the three ΔIle residues controls the magnitude of biological functions of 1.