title: Substituent effects on fluorescence properties of thiazolo[4,5-b]pyrazine derivatives.
abstract: Based on spectroscopic measurements and DFT calculations, fluorescence properties of thiazolo[4,5-b]pyrazine (TPy) derivatives with the phenyl group at the C2 position were studied. TPys were readily prepared from the corresponding amidopyrazines, which have a similar fluorescent core to a bioluminescence light emitter, Cypridina oxyluciferin. It was found that the introduction of electron-donating (methoxy and dimethylamino) groups onto the 2-phenyl moiety of the TPy derivatives, as well as the phenyl and 4-(dimethylamino)phenyl groups at C2 and C6, respectively, increases the fluorescence yield and appearance of solvatochromic character. The mechanism of increasing the fluorescence yield depending on the substituents is discussed. These findings provide useful information on designing new TPy fluorophores.
authors.affiliation: Department of Engineering Science, Graduate School of Informatics and Engineering, The University of Electro-Communications, Chofu, Tokyo 182-8585, Japan. thirano@uec.ac.jp.
authors.forename: Tatsuki
authors.initials: T
authors.lastname: Nakagawa
authors.forename: Minoru
authors.initials: M
authors.lastname: Yamaji
authors.forename: Shojiro
authors.initials: S
authors.lastname: Maki
authors.forename: Haruki
authors.initials: H
authors.lastname: Niwa
authors.forename: Takashi
authors.initials: T
authors.lastname: Hirano
mesh_terms: D005453:Fluorescence; D015394:Molecular Structure; D011719:Pyrazines / Q000737:chemistry*; D013057:Spectrum Analysis
chemical_list: D011719:Pyrazines