Tetrahedron Letters

Cross-coupling of 1-aryl-5-bromopyrazoles: regioselective synthesis of 3, 5-disubstituted 1-arylpyrazoles

X Wang, J Tan, K Grozinger

Index: Wang, Xiao-Jun; Tan, Jonathan; Grozinger, Karl Tetrahedron Letters, 2000 , vol. 41, # 24 p. 4713 - 4716

Full Text: HTML

Citation Number: 70

Abstract

The cross-coupling of 1-aryl-5-bromopyrazoles 4 with alkynes, vinyltins and arylboronic acids promoted by Pd (PPh3) 4 afforded unsymmetrical 3, 5-disubstituted 1-arylpyrazoles 5- 8 in excellent yields. 1-Aryl-5-bromopyrazoles 4 were prepared from their corresponding 1- arylpyrazolones 3 with PBr3 in refluxing acetonitrile.