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Chloroamine-T Promoted Three-Component Reaction of Aldehydes, Hydrazines and Fumarate Esters for the Construction of Tetra-substituted Pyrazole Derivatives

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 1 H NMR, 13 C NMR, IR and HRMS analysis.