Rhodium catalyzed 2-alkyl-benzimidazoles synthesis from benzene-1,2-diamines and tertiary alkylamines as alkylating agents

Substituted 2-alkyl-benzimidazoles were synthesized from benzene-1,2-diamine and tertiary amines as alkylating agent under polystyrene supported rhodium (Rh@PS) nanoparticles (NPs) catalyzed conditions. The heterogeneous rhodium catalyst was applied first time for the synthesis of 2-alkyl-benzimidazoles. The reaction followed through oxidation of alkylamines, transamination, and oxidative cyclisation with benzene-1,2-diamines for the corresponding products synthesis with good yields. The process is applicable for vast substrate scope, several functional groups are tolerable, and the Rh@PS catalyst is recyclable up to four cycles without significant loss in catalytic activity.

Automated summary

Substituted 2-alkyl-benzimidazoles were synthesized using polystyrene supported rhodium (Rh@PS) nanoparticles as catalyst, with good yields achieved through oxidation of alkylamines, transamination, and oxidative cyclisation. The process has a broad substrate scope, tolerance to various functional groups, and can be recycled up to four cycles without significant loss in catalytic activity.