3 (5)??(2??Hydroxyphenyl)??5 (3)??styrylpyrazoles: Synthesis and Diels− Alder Transformations

…, DCGA Pinto, JAS Cavaleiro, J Elguero

Index: Silva, Vera L. M.; Silva, Artur M. S.; Pinto, Diana C. G. A.; Cavaleiro, Jose A. S.; Elguero, Jose European Journal of Organic Chemistry, 2004 , # 21 p. 4348 - 4356

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Citation Number: 22

Abstract

Abstract Reactions between cinnamoyl (2-hydroxybenzoyl) methanes and hydrazine hydrate in acetic acid gave 3-(2-hydroxyphenyl)-5-styrylpyrazoles, while the corresponding reactions with phenylhydrazine yielded 5-(2-hydroxyphenyl)-1-phenyl-3-styrylpyrazoles as the major products and 3-(2-hydroxyphenyl)-1-phenyl-5-styrylpyrazoles as by-products. The reaction mechanism of this transformation is discussed. The first cycloaddition reactions ...