Abstract
Under solvent-free and ultrasonic irradiation conditions, efficient methods for the synthesis of 1,2-disubstitued benzimidazoles and 2-substitued benzothiazoles by employing rare-earth metal chlorides as catalysts are described. The methods have the advantages of broad generality, economical catalysts, good yields, simple operation, solvent-free condition, and ambient temperature.
GRAPHICAL ABSTRACT
![](/cms/asset/e2087168-97ab-49af-9b5c-8b9e0e48ffb7/lsyc_a_524337_o_uf0001.gif)
ACKNOWLEDGMENTS
The work was supported by the National Natural Science Foundation of China (20702001 and 20832001) and the Anhui Education Department (TD200707 and KJ2007A011).
Notes
a Benzaldehyde/o-phenylenediamine.
b Isolated yield.
Condition: Reaction of o-phenylenediamine with benzaldehyde under the optimum conditions.
a Isolated yield.