Novel (E)- and (Z)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles from (E)- and (Z)-3-styrylchromones: the unexpected case of (E)-3(5)-(2-hydroxyphenyl)-4-(4-nitrostyryl)pyrazoles
作者:Vera L.M. Silva、Artur M.S. Silva、Diana C.G.A. Pinto、José A.S. Cavaleiro、José Elguero
DOI:10.1016/j.tetlet.2007.03.147
日期:2007.5
An efficient synthetic method for the preparation of (E)- and (Z)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles has been developed. The reaction of (E)- and (Z)-3-styrylchromones with hydrazine hydrate afforded the corresponding (E)- and (Z)-4-styrylpyrazoles, respectively, saved 4′-nitro-derivatives where both (E)- and (Z)-4′-nitro-3-styrylchromones afforded (E)-3(5)-(2-hydroxyphenyl)-4-(4-nitrostyryl)pyrazoles
Wittig reactions of chromone-3-carboxaldehydes with benzylidenetriphenyl phosphoranes: a new synthesis of 3-styrylchromones
作者:Angela Sandulache、Artur M. S. Silva、Diana C. G. A. Pinto、L�cia M. P. M. Almeida、Jos� A. S. Cavaleiro
DOI:10.1039/b303554a
日期:——
An efficient route to 3-styrylchromones has been developed and applied to syntheses of several new derivatives. Wittig reactions of chromone-3-carboxaldehydes with some benzylic ylides gave a diastereomeric mixture of (E) and (Z)-3-styrylchromones that are separable by thin layer chromatography. The (Z)-isomers were the most abundant diastereomers independent of having electron-withdrawing or electron-donating
Synthesis of (E)- and (Z)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles
作者:Vera L. M. Silva、Artur M. S. Silva、Diana C. G. A. Pinto、José A. S. Cavaleiro、José Elguero
DOI:10.1007/s00706-008-0002-9
日期:2009.1
AbstractAn efficient synthesis method for the preparation of a series of new (Z)- and (E)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles was developed. The reaction of (Z)- and (E)-3-styrylchromones with hydrazine hydrate afforded the corresponding (Z)- and (E)-3(5)-(2-hydroxyphenyl)-4-styrylpyrazoles, except for nitro derivatives, where both (Z)- and (E)-4′-nitro-3-styrylchromones afforded (E)-3(5)-(2-hydroxyph