Masakazu Murakami

Chemoselective aerobic oxidation of primary alcohols catalyzed by a ruthenium complex

Abstract In the presence of secondary alcohols, primary alcohols are selectively oxidized to aldehydes under aerobic conditions by using a (nitrosyl)Ru(salen) complex as catalyst.

Ru(salen)-catalyzed asymmetric sulfimidation using arylsulfonyl azide

Abstract An (OC)Ru(II)(salen) complex was found to catalyze imidation of alkyl aryl sulfides in the presence of arylsulfonyl azide with high enantioselectivity as well as good chemical yield.

Chiral (OC)Ru(salen)-catalyzed tandem sulfimidation and [2,3]sigmatropic rearrangement: asymmetric CN bond formation

Abstract Asymmetric Cue5f8N bond formation was achieved in a highly enantioselective manner by using (OC)Ru(salen)-catalyzed sulfimidation and the subsequent [2,3]sigmatropic rearrangement: treatment of allyl aryl sulfides with p-toluenesulfonyl azide in the presence of a catalytic amount of (OC)Ru(salen) followed by hydrolysis of the resulting N-allyl-N-arylthio toluenesulfonamides provided N-allyl toluenesulfonamides of high enantiomeric excess.

Ubiquinone-5 is reduced by superoxide in the aerobic state by NADPH oxidase of guinea pig macrophages

The reduction of ubiquinone‐5 (Q1) by the phagocytosis‐specific NADPH oxidase of guinea pig macrophages was not inhibited by Superoxide dismutase (SOD) at concentrations usually used for O2 − assay but was inhibited at about 100‐times higher concentrations. Titration of the reaction with SOD and a comparison with that of xanthine oxidase showed that the inhibition was not due to the semiquinone oxidation accelerated by a removal of O2 − but due to the accelerated dismutation of O2 − which otherwise reduces the quinone. Molecular oxygens are therefore preferential electron acceptors in the NADPH oxidase even in the presence of Q1.