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
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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.
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