Tetrahedron letters

Microwave-assisted synthesis of 1-aryl-1H-indazoles via one-pot two-step Cu-catalyzed intramolecular N-arylation of arylhydrazones

C Pabba, HJ Wang, SR Mulligan, ZJ Chen, TM Stark…

Index: Pabba, Chittari; Wang, Hong-Jun; Mulligan, Susan R.; Chen, Zhen-Jia; Stark, Todd M.; Gregg, Brian T. Tetrahedron Letters, 2005 , vol. 46, # 44 p. 7553 - 7557

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Citation Number: 65

Abstract

A highly efficient one-pot two-step microwave procedure was developed for the synthesis of 1-aryl-1H-indazoles. Microwave heating of 2-halobenzaldehydes or 2-haloacetophenones with phenylhydrazines at 160° C for 10min quantitatively yielded the arylhydrazones, which were further cyclized to give 1-aryl-1H-indazoles via CuI/diamine-catalyzed N-arylation under microwave heating (160° C, 10min). Good to excellent yields were observed for 2- ...