磷酸氢二钾催化多组分一锅法反应合成1,4-二氢吡喃并[2,3-c]吡唑衍生物

绿色、简便、高效的催化四组分反应合成吡喃并2,3-c]吡唑类杂环化合物是当今有机化学领域的研究热点。 本文发展了在水与聚乙二醇(PEG-200)的混合液中,廉价易得的磷酸氢二钾(K₂HPO₄·3H₂O)催化乙酰乙酸乙酯、水合肼、芳香醛和丙二腈的多组分“一锅法”反应,合成一系列1,4-二氢吡喃并2,3-c]吡唑-5-腈衍生物,产率为88%~98%。 该方法避免了使用复杂昂贵的催化剂和繁琐的纯化过程。

Dipotassium Hydrogenphosphate Assisted Multi-component One-Pot Synthesis of 1,4-Hihydropyrano[2,3-c]pyrazole Derivatives

Catalytic one-pot four-component reaction is an ideal strategy for efficient and facile synthesis of pyrano2,3-c]pyrazoles. The efficacy of dipotassium hydrogenphosphate(K₂HPO₄·3H₂O) as a cheap and readily accessible catalyst for the synthesis of 1,4-dihydropyrano2,3-c]pyrazole-5-carbonitrile derivatives via one-pot four-component reaction of ethyl acetoacetate, hydrazine hydrate, aryl aldehydes, and malononitrile was described in this paper. These multi-component condensations proceeded smoothly in aqueous polyethylene glycol(PEG-200) and the corresponding products were obtained in 88%~98% yields. This improved protocol eliminates the problems associated with expensive complex catalyst and tedious purification procedures.