DBU mediated confluent approach for the one pot synthesis of novel 5-hydroxy pyrazolo[1,2-a][1,2,4]triazoles and their dehydration to novel pyrazolo[1,2-a][1,2,4]triazole derivatives

作者：Gupta Shruti; Saluja Pooja; Khurana Jitender M

来源：Tetrahedron, 2016, 72(27-28): 3986-3993.

DOI：10.1016/j.tet.2016.05.021

• 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)
• Pyrazolo-triazoles
• Multicomponent reactions
• Pharmacophore hybridization

A series of novel alkyl 5-hydroxy-7-aryl-5-methyl-1,3-dioxo-2-phenyl hexahydropyrazolo[1,2-a][1,2,4] triazole-6-carboxylates and alkyl 5-aryl-7-methyl-1,3-dioxo-2-phenyl-1,2,3,5-tetra hydropyrazolo[1,2-a] [1,2,4]triazole-6-carboxylates have been synthesized. The synthesis of hydroxy pyrazolo[1,2-a][1,2,4] triazoles has been achieved by DBU mediated one pot reaction of aromatic aldehydes, alkyl acetoacetates and 4-phenylurazole at 35 degrees C in ethanol-water (1:1). Dehydration of hydroxy pyrazolo[1,2-a][1,2,4]-triazoles has been achieved using conc. H2SO4 to afford dehydrated pyrazolo[1,2-a][1,2,4]triazoles in high yields. The structural assignments have been made by spectral data and unambiguously confirmed by X-ray analysis. Good yields, operational simplicity and moderate conditions are the advantages of the reactions.

• 出版日期2016-7-7