Benzothiazole possessing reversible and reusable selective chemosensor for fluoride detection based on inhibition of excited state intramolecular proton transfer
摘要:
A series of three benzothiazole derivatives BTBAs based on aryl amide groups have been developed, whose photophysical properties were remarkably changed by the presence of -OCH3 and -NO2 groups at para-position of aryl amides. Among these chemosensors, BTBA-OCH3 showed fluoride selectivity in its absorbance and emission behavior among the various interfering anions, along with conspicuous color change from colorless to yellowish green color. Substantially red shifted absorption as well as fluorescence band of BTBA-OCH3 in DMSO, was observed upon addition of F- ions. Inhibition of Excited State Intramolecular Proton Transfer (ESIPT) in sensor-anion deprotonated complex was suggested to be the signaling mechanism. H-1 NMR titrations of the sensor with F- ions also supported deprotonation process. In particular, the spectral responses of this chemosensor could be tuned from side to side alternatively by adding F- and HSO4- anions in DMSO solvent. (C) 2016 Elsevier B.V. All rights reserved.
The Rh(III)-catalyzed amidation of C(sp2)-H bonds has been reported by employing the N-methoxyamide as a novel amino source. An excellent level of functional group tolerance can be achieved when N-methoxyamide derivatives are used as the amidating reagents. Importantly, several known bioactive compounds such as Aminalon, Pregabalin, Gabapentin, and Probenecid can be transformed to effective amidating
Intermolecular coupling of 2-iodoanilides with benzoxazoles: synthesis of N-(2-Benzoxazol-2-ylphenyl)benzamides via C–H activation
作者:Swarnendu Sasmal、Indira Sen、Roger G. Hall、Sitaram Pal
DOI:10.1016/j.tetlet.2015.01.150
日期:2015.3
Using CuI/xantphos/Pd(OAc)(2) catalytic system, the intermolecular C-C cross coupling between benzoxazoles and ortho-haloanilides has been developed in moderate to good yields. The procedure tolerates a series of functional groups on benzoxazole, such as ester, chloro, methyl, and methoxy groups. This divergent approach provides access to various N-(2-Benzoxazol-2-ylphenyl)amides. (C) 2015 Elsevier Ltd. All rights reserved.
Rh-Catalyzed C–H Amidation of 2-Arylbenzo[<i>d</i>]thiazoles: An Approach to Single Organic Molecule White Light Emitters in the Solid State
A Rh-catalyzed direct C-H amidation of 2-arylbenzo[d]thiazoles has been developed. The transformation is characterized by its efficiency, external oxidant-free conditions, and the avoidance of a traditional three-step process consisting of nitration, ammoniation, and amidation. Furthermore, several of the prepared molecules exhibit bright white-light emission in the solid state.