Highly selective synthesis of libraries of 1,2-disubstituted benzimidazoles using silica gel soaked with ferric sulfate

An efficient and highly selective synthesis of functionalized 1,2-benzimidazoles has been developed under solvent-free conditions at ambient temperature using eco-friendly ferric sulfate soaked with silica [iron(III)sulfate-silica]. Recycling of the solid support up to six runs was investigated with appreciable yield and selectivity of the product.