Moderately Oxidizing Thioxanthylium Organophotoredox Catalysts for Radical-Cation Diels-Alder Reactions.

Moderately oxidizing thioxanthylium photoredox catalysts that operate under irradiation with green light have been developed. These catalysts exhibit relatively moderate excited-state reduction potentials [(C*/C) = 1.75-1.

Redox Potential Controlled Selective Oxidation of Styrenes for Regio- and Stereoselective Crossed Intermolecular [2 + 2] Cycloaddition Organophotoredox Catalysis.

A redox potential controlled intermolecular [2 + 2] cross-cycloaddition has been developed in the presence of a thioxanthylium photoredox catalyst. Electron-rich styrenes such as β-bromostyrene ( = +1.61 V vs SCE) were selectively oxidized by a thioxanthylium photoredox catalyst ( (C*/C) = +1.

Access to Electron-Deficient 2,2-Disubstituted Chromanes: A Highly Regioselective One-Pot Synthesis via an Inverse-Electron-Demand [4 + 2] Cycloaddition of -Quinone Methides.

We report the one-pot synthesis of 2,2-disubstituted chromanes with electron-withdrawing substituents. This reaction provides a simple yet efficient route to a wide range of electron-deficient chromanes in high yield and excellent regioselectivity. The reaction of salicylaldehyde with 1,1-disubstituted ethylenes smoothly furnishes these electron-deficient chromanes, which can be further transformed into functionalized chromanes or chromene.

Friedel-Crafts approach to the one-pot synthesis of methoxy-substituted thioxanthylium salts.

An efficient synthesis of methoxy-substituted thioxanthylium salts has been developed. The reaction of diaryl sulfides with benzoyl chlorides in the presence of TfOH smoothly proceeded to give the desired thioxanthylium salts in good yields. In their UV-vis spectra, the maximum absorption wavelengths of methoxy-functionalized thioxanthylium salts were observed at around 460 nm, which show a drastic red shift compared to the parent thioxanthylium salts.

Identification of a gingipain-sensitive surface ligand of Porphyromonas gingivalis that induces Toll-like receptor 2- and 4-independent NF-kappaB activation in CHO cells.

Porphyromonas gingivalis is a major periodontal pathogen that has the pathogenic proteinases Arg-specific gingipain and Lys-specific gingipain. We previously found that a cell surface component on P. gingivalis is able to induce Toll-like receptor 2 (TLR2)- and TLR4-independent signaling in 7.

Gingipains inactivate a cell surface ligand on Porphyromonas gingivalis that induces TLR2-and TLR4-independent signaling.

Arginine-specific gingipain and lysine-specific gingipain are two major cysteine proteinases produced by Porphyromonas gingivalis. To clarify the role of gingipains in the interaction between P. gingivalis and the innate immune system, CHO reporter cells expressing TLR2 or TLR4 were stimulated with wildtype or gingipain-deficient P.

Behavioral changes in metallothionein-null mice after the cessation of long-term, low-level exposure to mercury vapor.

The neurobehavioral changes in wild-type and metallothionein (MT)-null mice after the cessation of long-term, low-level exposure to Hg0 were investigated. MT-null and wild-type females were continuously (24 h/day) exposed to mercury vapor (Hg0) at 0.055 mg/m3 (range: 0.