Studies On Rhodium-catalyzed Synthesis Of 2-Alkylbenzimidamides From N-Hydroxylamines

2-Alkyl-benzimidazoles represent an important class of heterocyclic compounds which are widely found in pharmaceuticals and natural products.Pharmaceuticals incorporating this privileged motif display important bioactivity,which could inhibit HBV-DNA replication in vitro with low cytotoxicity,and could be applied as the inhibitor of poly(ADP-ribose)polymerase(PARP)in treatment of cancer,which can potentiate the efficacy of radiation and several cytotoxic agents with good penetration into the brain.However,there are some challenges with the synthesis of 2-alkyl benzimidazoles,such as high environmental pollution,preactivation of substrates,poor atomic economy and low efficiency.Recently,the direct C-H bond functionalizations have been developed as the most facility,straightforward and atom-economic protocols to construct C-C and C-X bonds.In this thesis,we mainly study the synthesis of 2-alkylbenzimidazole and its derivatives through the direct C-H amination of imidamides with hydroxylamine catalyzed by Cp*Rh(III).This convenient,straightforward and environmentally friendly transformation could proceed smoothly with high regioselectivity,efficiency,good tolerance of functional groups,and under the mild reaction conditions.A series of 2-alkyl-stustituted benzimidazole were obtained in high yields.