Tomohiko Ohwada

N-Nitrosamines can be considered as potential nitric oxide (NO)/nitrosonium ion (NO(+)) donors. However, the relation of the structures of N-nitrosamines, in particular of aliphatic N-nitrosamines, to the characteristics of release of NO or NO(+) remains unclear. Here we show that aliphatic N-nitrosoamines of 7-azabicyclo[2.2.1]heptanes can undergo heterolytic N-NO bond cleavage. On the basis of the observation of reduced rotational barriers of the N-NO bonds in solution and nitrogen-pyramidal s

GPR34 is a G protein-coupled receptor belonging to the P2Y family. Here, we attempted to resolve conflicting reports about whether it is a functional lysophosphatidylserine (LysoPS) receptor. In HEK293 cells expressing human, mouse or rat GPR34 and Gα chimera between Gαq and Gαi1(Gq/i1), LysoPS quickly elevated intracellular Ca(2+) ion levels ([Ca(2+)](i)). LysoPS also stimulated alkaline phosphatase (AP)-tagged TGFα (AP-TGFα) release in GPR34-expressing HEK293 cells and induced the migration of

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFriedel-Crafts-type reactions involving di- and tricationic species. Onium-allyl dications and O,O-diprotonated aci-nitro species bearing a protonated carbonyl groupTomohiko Ohwada, Naoko Yamagata, and Koichi ShudoCite this: J. Am. Chem. Soc. 1991, 113, 4, 1364–1373Publication Date (Print):February 1, 1991Publication History Published online1 May 2002Published inissue 1 February 1991https://pubs.acs.org/doi/10.1021/ja00004a044https://doi.org/10.1021/ja

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrbital-Controlled Stereoselections in Sterically Unbiased Cyclic SystemsTomohiko OhwadaView Author Information Faculty of Pharmaceutical Sciences, Nagoya City University, Tanabe-dori, Mizuho-ku, Nagoya, 467, Japan, and Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113, Japan Cite this: Chem. Rev. 1999, 99, 5, 1337–1376Publication Date (Web):April 28, 1999Publication History Received16 October 1998Re

It has been experimentally established that the proton affinities (PA), as well as the solution basicities (pK(BH)(+)), of aziridine derivatives are much smaller than those of the corresponding pyrrolidines and piperidines, though the basic strength of azetidines is close to those of pyrrolidines and piperidines. A simple idea of dependence of the basic strength on bond angles seems to be invalid. Because the basicity of cyclic amines is a fundamental property in organic chemistry, we revisited

Fluorescent polymeric thermometers consisting of only N-alkylacrylamide and fluorescent components show rather low temperature resolution in their functional ranges (ca. 15-50 degrees C) because of the occurrence of intermolecular aggregation, which causes hysteresis in their fluorescence response to changes in temperature. By adding an ionic component to prevent such intermolecular aggregation, we obtained four fluorescent polymeric thermometers that offer high temperature resolution (<0.2 degr

Although many organic/inorganic compounds that release nitric oxide (NO) upon photoirradiation (phototriggered caged-NOs) have been reported, their photoabsorption wavelengths mostly lie in the UV region, because X-NO bonds (X=heteroatom and metal) generally have rather strong π-bond character. Thus, it is intrinsically difficult to generate organic compounds that release NO under visible light irradiation. Herein, the structures and properties of N-pyramidal nitrosamine derivatives of 7-azabicy

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReaction of diphenylmethyl cations in a strong acid. Participation of carbodications with positive charge substantially delocalized over the aromatic ringsTomohiko. Ohwada and Koichi. ShudoCite this: J. Am. Chem. Soc. 1988, 110, 6, 1862–1870Publication Date (Print):March 1, 1988Publication History Published online1 May 2002Published inissue 1 March 1988https://pubs.acs.org/doi/10.1021/ja00214a031https://doi.org/10.1021/ja00214a031research-articleACS Pu