Diversification of Pyrazoles by Microwave-assisted Ligand Free CopperCatalyzed N-Arylation

摘要

Pyrazole and its derivatives exhibit interesting chemical and biological properties, so the derivatives are widely used in pharmaceuticals, agrochemicals, food additives, dyes, materials, and cosmetic coloring agents. Several synthetic methods for facile preparation of pyrazole derivatives have been reported. The N-arylpyrazole moiety is aparticularly interesting synthetic target that has exhibited a broad spectrum of biological activities. For example, several N-arylated pyrazoles exhibit diverse pharmaceutically relevant characteristics such as anti-infiammatory, antitumor, antiviral, and ORL1 antagonist activity. The N-arylpyrazoles are also agrochemically relevant and have been shown to have insecticidal, herbicidal, and fungicidal activity. In addition, several pyrazole derivatives have been used as ligands for the formation of iridium complexes in organic light-emitting diode (OLED) materials. Over the last two decades, many mild and efficient methods have been reported that accomplish heterocycle N-arylation using catalytic palladium (Pd) and copper (Cu) reactions.