Paper Info
Title
Mechanistic Insights Into N-Bromosuccinimide-Promoted Synthesis Of Imidazo[1,2-A]Pyridine In Water: Reactivity Mediated By Substrates And Solvent
Abstract
The mechanism of N-Bromosuccinimide (NBS) promoted synthesis of imidazo[1,2-a]pyridine in water as well as the effective activation modes of NBS was investigated by Density Functional Theory (DFT) calculations. Two main mechanisms that differ in the reaction sequence of substrate were explored: styrene with NBS then followed by 2-aminopyridine (M1) or simultaneously with NBS and 2-aminopyridine (M2), and water-assisted M2 is the more favored one. We found that the adding sequence of 2-aminopyridine affects profoundly on the title reaction. Moreover, upon the assistance of water and NBS, the preferential mechanistic scenario involves three major processes: nucleophilic addition, stepwise H-shift and intramolecular cyclization, three-step deprotonation, rather than a classical bromonium ion species. Specifically, the cooperative interaction of NBS and water plays a critical role in the title reaction. Water acts as solvent, reactant, anchoring, stabilizer, and catalyst. NBS promotes the above three processes by the effective forms of Br+/Br-, succinimide, and its ethanol isomer. Furthermore, noncovalent interactions between catalysts and substrates are responsible for the different reactive activities of M1 and M2. Our results indicate that simultaneous adding of all reactants is recommended toward economical synthesis. (c) 2018 Wiley Periodicals, Inc.
Year
DOI
Venue
2018
10.1002/jcc.25564
JOURNAL OF COMPUTATIONAL CHEMISTRY
Keywords
Field
DocType
mechanism, DFT calculations, H2O-NBS cooperation, noncovalent interaction
Organic chemistry,N-Bromosuccinimide,Computational chemistry,Chemistry,Pyridine,Solvent,Mechanism (philosophy)
Journal
Volume
Issue
ISSN
39
27
0192-8651
Citations 
PageRank 
References 
0
0.34
0
Authors
5
Name
Order
Citations
PageRank
Min Qian100.34
Bowen Qin200.34
Haiyan Yuan320.92
Wenliang Li411.36
Jingping Zhang597.30