36 research outputs found
Advanced flavin catalysts elaborated with polymers
A variety of biological redox reactions are mediated by flavoenzymes due to the unique redox activity of isoalloxazine ring systems, which are found in flavin cofactors. In the field of synthetic organic chemistry, the term âflavinâ is generally used for not only isoalloxazines but also related molecules including their isomers and some analogues, and those having catalytic activity are called flavin catalyst. Flavin catalysts are typically metal-free, and their catalytic activity can be readily accessed using mild terminal oxidants such as H2O2 and O2; therefore, redox reactions with these compounds have great promise as alternatives to reactions with conventional metal catalysts for the sustainable production of important chemicals. We recently became interested in using polymers for the development of flavin catalysts, especially to improve their practicality and advance the field of catalysis. Here, we summarize our recent research on such flavin-polymer collaborations including the development of facile preparation methods for flavin catalysts using polymers, readily reusable polymer-supported flavin catalysts, and flavin-peptide-polymer hybrids that can catalyze the first flavoenzyme-mimetic aerobic oxygenation reactions
Safeguarding world wheat and barley production against Russian wheat aphid: An international germplasm evaluation and pre-breeding initiative
No abstract availabl
2,4,5-Triphenylisothiazol-3(2H)-one 1,1-dioxides as inhibitors of human leukocyte elastase.
A series of substituted 2,4,5-triphenylisothiazol-3(2H)-one 1,1-dioxides 9 was synthesized and investigated as inhibitors of human leukocyte elastase (HLE). All compounds were found to inhibit HLE in a time-dependent manner and most of them exhibited kobs/[I] values > 300 Mâ 1sâ 1. The most potent 3-oxosultam of this series was 9l (kobs/[I] = 2440 Mâ 1sâ 1). Kinetic investigations performed with 9g and different substrate concentrations did not allow to clearly distinguish between a competitive or noncompetitive mode of inhibition. A more complex interaction is supported by the failure of a linear dependency of kobs values on the inhibitor concentration.Michael GĂŒtschow, Markus Pietsch, Andrea Themann, Janine Fahrigâand BĂ€rbel Schulzeâhttp://informahealthcare.com/doi/abs/10.1080/14756360500148783?journalCode=en