A Practical, Metal-Free Synthesis of 1H-Indazoles
journal contributionposted on 06.03.2008, 00:00 by Carla M. Counceller, Chad C. Eichman, Brenda C. Wray, James P. Stambuli
The synthesis of 1H-indazoles is achieved from o-aminobenzoximes by the selective activation of the oxime in the presence of the amino group. The reaction occurs with a variety of substituted o-aminobenzoximes using a slight excess of methanesulfonyl chloride and triethylamine at 0−23 °C and is amenable to scale-up. The synthesis of 1H-indazoles under these conditions is extremely mild compared with previous synthetic approaches and affords the desired compounds in good to excellent yields.