Xanthan Sulfuric Acid： An Efficient Bio-supported and Recy- clable Solid Acid Catalyst for the Synthesis of 2-Aryl Thiadiazolo Benzimidazoles

Xanthan sulfuric acid is an efficient solid acid catalyst for the preparation of 2-aryl benzimidazoles in excellent yields. This method is applicable for the reaction of benzo[c][ 1,2,5]thiadiazole-4,5-diamine with aldehydes by sim- ple physical grinding at room temperature. The salient features of the present methodology is cheaper process, easy synthesis of stable catalyst and the catalyst can be easily recycled without significant loss of activity.