Publications by authors named "Satoru Kumagai"
Article Synopsis
- The study discusses a method called Hiyama coupling that produces chiral triptycenes by transferring substituents from silicon between two parts of the molecule.
- The reaction relies on the proximity of these substituents, crucial for forming an oxy-palladacycle and activating the silyl group, which helps in a process called σ-bond metathesis.
- The final result includes various chiral triptycenes, with the study also achieving optical resolution for the first time, resulting in an optically active version of the compound.
A Pd-catalyzed domino reaction of 1,8,13-tribromo-9-methoxytriptycenes is reported. Under conventional Suzuki coupling conditions, the triptycenes underwent multiple transformations to give 1,9-bridged triptycenes. Based on mechanistic investigations, a single Pd catalyst functions as Pd , Pd and Pd species to catalyze four distinct processes: (1) aryl to alkyl 1,5-Pd migration, (2) intramolecular arylation, (3) homocoupling of phenylboronic acid and (4) Suzuki coupling.
View Article and Find Full Text PDFWe have found that a 12-lipoxygenase metabolite of arachidonic acid, 12(S)-hydroxy-5Z,8Z,10E,14Z-eicosatetraenoic acid (12-HETE), induces cAMP production in human normal fibroblast TIG-1 cells. This phenomenon was not observed in other cells tested including human embryonic kidney HEK293 cells. We have speculated that this specific response might be influenced by the kinds of isoform of adenylyl cyclase (AC) present in cells.
View Article and Find Full Text PDFWe have found that tissue-type transglutaminase (tTG), also called TGc, TGase2 and Galpha(h), has the activity of protein disulphide isomerase (PDI). We have shown that tTG converts completely reduced/denatured inactive RNase A molecule to the native active enzyme. The PDI activity of tTG was strongly inhibited by bacitracin, which is a frequently used inhibitor of conventional PDI activity.
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