52214-61-6Relevant articles and documents
Synthesis, photophysical characterization, CASSCF/CASPT2 calculations and CT-DNA interaction study of amino and azido benzazole analogues
Gil, Eduarda S.,da Silva, Cláudia B.,Nogara, Pablo A.,da Silveira, Carolina H.,da Rocha, Jo?o B.T.,Iglesias, Bernardo A.,Lüdtke, Diogo S.,Gon?alves, Paulo F.B.,Rodembusch, Fabiano S.
, (2020)
This work describes the synthesis and photophysical investigation of amino and azido benzazoles. The amino derivatives were obtained by condensation reaction between ortho-substituted anilines and p-aminobenzoic in polyphosphoric acid. The respective azides were synthesized by reaction of diazonium salts from the previously prepared amines with sodium azide. These compounds present absorption maxima in the UV-A region, nm ascribed to fully spin and symmetry electronic transitions. All compounds presented a main fluorescence emission in the UV-A to the violet region with a relatively large Stokes shift. The latter related to a solvent dependence. The amino derivatives presented higher values to the fluorescence quantum yields in despite of the azido analogues. DFT, TD-DFT and multiconfigurational calculations (SA-CASSCF and MS-CASPT2) were performed in order to investigate the photophysical features of these molecules, mainly on the azide derivatives, where the main interest was the investigation of the intrinsic fluorescence quenching present in these compounds. In this sense, it was observed that the weak fluorescence emission observed in the azide compounds could be related to the dissociative character of the S1 state, which reaches a conical intersection point between S1/S0 states, and through this point, goes back to the ground state by a nonradioactive decay. In addition, the DNA binding assays by UV–Vis absorption and fluorescence emission methodologies indicated that the benzazoles presented strong interaction with CT-DNA, which could be attributed to π-stacking and/or intermolecular hydrogen-bonding. Docking was also performed to better understand the observed interaction.
Antitumor benzothiazoles. Part 2. Formation of 2,2'-diaminobiphenyls from the decomposition of 2-(4-azidophenyl)benzazoles in trifluoromethanesulfonic acid
Stevens, Malcolm F. G.,Shi, Dong-Fang,Castro, Angeles
, p. 83 - 94 (2007/10/03)
Decomposition of 2-(2-azidophenyl)- and 2-(3-azidophenyl)-benzothiazoles in trifluoromethanesulfonic acid generates ?-carbocations.These reactive intermediates have been trapped by triflate anion with the nucleophile substituting para to the original azido group to yield triflate-substituted arylamines. 2-(4-Azidophenyl)-benzothiazoles and -benzoxazoles behave differently: triflate-substituted arylamines are accompanied by symmetrical or unsymmetrical benzazolyl-substituted 2,2'-diaminobiphenyls as major products.These biphenyls have been identified by their characteristic 1H and 13C NMR spectra. 2,2'-Diaminobiphenyls are formed by initial C-C coupling interactions between the ?-carbocations and undecomposed 2-(4-azidophenyl)benzazoles and not by benzidine-type rearrangements as originally proposed.Symmetrical 2,2'-diaminobiphenyls have been oxidized by (diacetoxyiodo) benzene to give novel benzazolyl-substituted benzocinnolines.
