One-pot synthesis of highly functionalized pyrano[2,3-c]pyrazole-4,4′-diacetate and 6-oxo-pyrano[2,3-c]pyrazole derivatives catalyzed by urea

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• 作者：Wenbo Li ; Reyhangul Ruzi ; Keyume Ablajan ; ^{ablajan209@hotmail.com} ; Zulpiya Ghalipt
• 关键词：Urea-catalyzed ; Pyrano[2 ; 3-c]pyrazole ; Multi-component reaction ; One-pot synthesis
• 刊名：Tetrahedron
• 出版年：2017
• 出版时间：12 January 2017
• 年：2017
• 卷：73
• 期：2
• 页码：164-171
• 全文大小：978 K
• 卷排序：73

文摘

A facile one-pot, multicomponent protocol for the synthesis of 1,4-dihydro-pyrano[2,3-c]pyrazole derivatives using a urea catalyst is reported. This transformation proceeds via a four-component reaction of ethyl acetoacetate, a hydrazine, 3-oxo-pentanedioic acid dimethyl ester, and malononitrile. The bifunctional nature of urea means that it catalyzes many steps in this transformation, including domino Knoevenagel condensation, Michael addition, and ring opening and closing reactions. This synthetic method has several advantages, including good yield, simple work-up, harmless by-products, and simple purification.