Carbazole and its derivatives are widely used in the field of medicine and photoelectric materials. A kind of stable cyclic hypervalent iodine reagents containing carbazole group was developed, which belong to benziodoxole compounds. In the presence of Cu(I) catalyst, these reagents reacted with aromatic substrates to give N-aryl carbazole derivatives. The reaction conditions are mild and suitable for a variety of electron-rich arenes. And a radical mechanism was proposed.

Pyrazoles, a class of five-membered nitrogen-containing heterocyclic compounds, showed antibacterial, anticancer and antioxidative activity, and so on. They also served as important intermediates in organic synthesis. To develop the general and straightforward methods to their synthesis is of great significance. In this paper, a series of tetra-substituted pyrazoles were synthesized from aldehydes, hydrazines and fumarate esters by three-component[3+2] cycloaddition reaction in the presence of chloroamine-T with 60%~87% yields. Their structures were confirmed by ¹H NMR, ¹³C NMR, IR and HRMS analysis.