title: Palladium-catalyzed microwave-assisted direct arylation of imidazo[2,1-b]thiazoles with aryl bromides: synthesis and mechanistic study.
abstract: A palladium-catalyzed direct C-H arylation of various imidazo[2,1-b]thiazoles with a range of aryl bromides under microwave irradiation is described. 6-Phenyl substituted imidazo[2,1-b]thiazoles could be regioselectively C-5 arylated using the developed protocol. The utility of this method enables the representative coupling product to be achieved by a sequential one-pot reaction. Density functional theory (DFT) calculations show that this arylation proceeds via a concerted metalation-deprotonation (CMD) pathway, which is in agreement with our experimental results. This work provides a convenient access to a variety of biologically active imidazo[2,1-b]thiazole derivatives. Also, it enriches the mechanism study of site-selective C-H arylation in fused heterocycles, and offers a valuable guide to design highly efficient catalytic systems for the preparation of similar compounds.
authors: State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, P. R. China. hw-jing@163.com.
authors: Yi-Shuo
authors: YS
authors: Zhu
authors: Benyi
authors: B
authors: Shi
authors: Ran
authors: R
authors: Fang
authors: Xiaoxuan
authors: X
authors: Wang
authors: Huanwang
authors: H
authors: Jing
mesh_terms: D001965:Bromides / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D008872:Microwaves; D010165:Palladium / Q000737:chemistry*; D066244:Proton Magnetic Resonance Spectroscopy; D011522:Protons; D013816:Thermodynamics; D013844:Thiazoles / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D001965:Bromides; D011522:Protons; D013844:Thiazoles; D010165:Palladium