Regulatory molecules for the 5-HT3 receptor ion channel gating system
摘要:
Substituted benzoxazole derivatives which possess a nitrogen containing heterocycle at C2 are selective partial agonists of the 5-HT3 receptor. Alteration of substituents on the benzoxazole nucleus affords both agonist-like and antagonist-like compounds, and uniquely modifies the function of the 5-HT3 receptor ion channel gating system. SAR and corroborative computational docking study for these partial agonists successfully explained structure and function of the 5-HT3 receptor. (c) 2007 Elsevier Ltd. All rights reserved.
Catalyst- and Reagent-Free Electrochemical Azole C−H Amination
作者:Youai Qiu、Julia Struwe、Tjark H. Meyer、João C. A. Oliveira、Lutz Ackermann
DOI:10.1002/chem.201802832
日期:2018.9.3
Catalyst‐ and chemical oxidant‐free electrochemical azole C−H aminations were accomplished via cross‐dehydrogenative C−H/N−H functionalization. The catalyst‐free electrochemical C−H amination proved feasible on azoles with high levels of efficacy and selectivity, avoiding the use of stoichiometric oxidants under ambient conditions. Likewise, the C(sp3)−H nitrogenation proved viable under otherwise
Heterogeneously Porous γ-MnO<sub>2</sub>-Catalyzed Direct Oxidative Amination of Benzoxazole through CH Activation in the Presence of O<sub>2</sub>
作者:Provas Pal、Arnab Kanti Giri、Harshvardhan Singh、Subhash Chandra Ghosh、Asit Baran Panda
DOI:10.1002/asia.201402057
日期:2014.9
Oxidative amination of azoles through catalyticCHbond activation is a very important reaction due to the presence of 2‐aminoazoles in several biologically active compounds. However, most of the reported methods are performed under homogeneous reaction conditions using excess reagents and additives. Herein, we report the heterogeneous, porous γ‐MnO2‐catalyzed direct amination of benzoxazole with
Iodine-Catalyzed Amination of Benzoxazoles: A Metal-Free Route to 2-Aminobenzoxazoles under Mild Conditions
作者:Manjunath Lamani、Kandikere Ramaiah Prabhu
DOI:10.1021/jo201402a
日期:2011.10.7
route of oxidative amination of benzoxazole by activation of C–H bonds with secondary or primary amines in the presence of catalytic iodine in aqueous tert-butyl hydroperoxide proceeds smoothly at ambient temperature under neat reaction condition to furnish the high yield of the aminated product. This user-friendly method to form C–Nbonds produces tertiary butanol and water as the byproduct, which are
Merging the ring opening of benzoxazoles with secondary amines and an iron-catalyzed oxidative cyclization towards the environmentally friendly synthesis of 2-aminobenzoxazoles
作者:Daqian Xu、Wenfang Wang、Chengxia Miao、Qiaohong Zhang、Chungu Xia、Wei Sun
DOI:10.1039/c3gc41206g
日期:——
A facile and environmentally friendly method was developed through merging the ring opening of benzoxazoles with secondary amines and an iron-catalyzed oxidative cyclization towards the synthesis of 2-aminobenzoxazoles. In the oxidative cyclization step, with catalytic amounts of FeCl and aqueous H2O2 as a green oxidant, highly desirable 2-aminobenzoxazoles were isolated in excellent yields of up to 97%. A plausible radical process is proposed for the oxidative cyclization on the basis of mechanistic studies.
Several modified 2-piperazinyl benzoxazole derivatives, which exhibit an agonistic effect on gastrointestinal motility, were synthesized and their effects on the contraction of guinea-pig ileum were examined. The quaternary piperazinyl benzoxazole structure has a restricted conformation and stereostructure compared to those of the other 5-HT3 receptor agonists, serotonin and meta-chlorophenylbiguanide. The mutual positions of the aromatic ring, nitrogen atom and terminal amine are considered to form the pharmacophore of the 5-HT3 receptor agonist in the gut. In the serotonin-evoked reflex bradycardia [Bezold-Jarisch (B-J) reflex] inhibition test using rats the B-J reflex-inducing ratio was different for each synthesized compound. These results suggest that, in these 5-HT3 receptor agonists, the substituents of the benzoxazole ring influence the B-J reflex-inducing activity in rats.