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Synfacts 2007(11): 1135-1135
DOI: 10.1055/s-2007-991295
DOI: 10.1055/s-2007-991295
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York
Reductive Cyclization of o-Nitrophenylazophenols to Benzotriazoles
G.-B. Liu*, H.-Y. Zhao, H.-J. Yang, X. Gao, M.-K. Li, T. Thiemann
Fudan University, Shanghai, P. R. of China and Kyushu University, Fukuoka, Japan
Further Information
Publication History
Publication Date:
23 October 2007 (online)
Significance
Demonstrated is an efficient cyclization of o-nitrophenylazophenols to aryl triazoles in water using powdered zinc as the reductant. A simple work-up procedure is presented in which no extraction using organic solvents was required, and the products were obtained by filtration from the acidified reaction mixture. This avoidance of organic solvents makes the reported procedure potentially useful from industrial and environmental points of view. The substrate scope was fairly well studied. Lowering the reaction temperature as well as lowering the concentration of alkaline leads to decreased yields. No metals other than zinc as reductants were studied.