77514-31-9Relevant articles and documents
Catalytic Enantioselective Synthesis of Heterocyclic Vicinal Fluoroamines by Using Asymmetric Protonation: Method Development and Mechanistic Study
Ashford, Matthew W.,Xu, Chao,Molloy, John J.,Carpenter-Warren, Cameron,Slawin, Alexandra M. Z.,Leach, Andrew G.,Watson, Allan J. B.
supporting information, p. 12249 - 12255 (2020/08/21)
A catalytic enantioselective synthesis of heterocyclic vicinal fluoroamines is reported. A chiral Br?nsted acid promotes aza-Michael addition to fluoroalkenyl heterocycles to give a prochiral enamine intermediate that undergoes asymmetric protonation upon rearomatization. The reaction accommodates a range of azaheterocycles and nucleophiles, generating the C?F stereocentre in high enantioselectivity, and is also amenable to stereogenic C?CF3 bonds. Extensive DFT calculations provided evidence for stereocontrolled proton transfer from catalyst to substrate as the rate-determining step, and showed the importance of steric interactions from the catalyst's alkyl groups in enforcing the high enantioselectivity. Crystal structure data show the dominance of noncovalent interactions in the core structure conformation, enabling modulation of the conformational landscape. Ramachandran-type analysis of conformer distribution and Protein Data Bank mining indicated that benzylic fluorination by this approach has the potential to improve the potency of several marketed drugs.
Aza-boron-diquinomethene complexes bearing N-aryl chromophores: Synthesis, crystal structures, tunable photophysics, the protonation effect and their application as pH sensors
Zhu, Xiaolin,Huang, Hai,Liu, Rui,Jin, Xiaodong,Li, Yuhao,Wang, Danfeng,Wang, Qiang,Zhu, Hongjun
, p. 3774 - 3782 (2015/04/22)
A series of aza-boron-diquinomethene complexes (1a-1e) bearing different N-aryl chromophores were synthesized and characterized by multinuclear NMR spectroscopy, X-ray crystallography, optical absorption and emission spectroscopy, and elemental analysis. These robust thermal complexes possess tunable intense luminescence from blue to red with relatively high emission quantum yields. The introduction of different N-aryl chromophores into the aza-BODIQU core significantly tuned the emission colors. The relationship between their structures and properties was investigated systematically via spectroscopic methods and simulated by density functional theory (DFT) calculations. Additionally, the application of 1c as a pH sensor with a remarkable colour-changing property has been investigated. All these results indicate that these complexes exhibit robust thermal stability, tunable photophysical properties, relatively high photoluminescence quantum yields and protonation effect, making these complexes potential candidates for pH sensors, bioimaging probes and organic light-emitting materials.
Regioselective bromination of fused heterocyclic N-oxides
Wengryniuk, Sarah E.,Weickgenannt, Andreas,Reiher, Christopher,Strotman, Neil A.,Chen, Ke,Eastgate, Martin D.,Baran, Phil S.
supporting information, p. 792 - 795 (2013/04/10)
A mild method for the regioselective C2-bromination of fused azine N-oxides is presented, employing tosic anhydride as the activator and tetra-n-butylammonium bromide as the nucleophilic bromide source. The C2-brominated compounds are produced in moderate to excellent yields and with excellent regioselectivity in most cases. The potential extension of this method to other halogens, effecting C2-chlorination with Ts2O/TBACl is also presented. Finally, this method could be incorporated into a viable one-pot oxidation/bromination process, using methyltrioxorhenium/urea hydropgen peroxide as the oxidant.