A re-engineering approach: synthesis of pyrazolo[1,2-a]pyrazoles and pyrano[2,3-c]pyrazoles via an isocyanide-based four-component reaction under solvent-free conditions
been developed for the efficient synthesis of pyrazolo[1,2-a]pyrazoles and pyrano[2,3-c]pyrazoles via an isocyanide-based four-component reaction of dialkyl acetylenedicarboxylates, isocyanides, and ethyl acetoacetate with hydrazine hydrate or phenylhydrazine. The reactions were carried out under solvent- and catalyst-free conditions at mild temperatures and short times in good yields.
已开发出一种基于重新设计方法的新方案,用于通过基于异氰化物的四烷基乙酰二羧酸二烷基酯的四组分反应,高效合成吡唑并[1,2- a ]吡唑和吡喃并[2,3- c ]吡唑,异氰化物和乙酰乙酸乙酯与水合肼或苯肼。反应在无溶剂和无催化剂的条件下,在温和的温度和短时间下以良好的收率进行。
Reaction between isocyanides and dialkyl acetylenedicarboxylates in the presence of 2,4-dihydro-3H-pyrazol-3-ones. One-pot synthesis of highly functionalized 7-oxo-1H,7H-pyrazolo[1,2-a]pyrazoles
The reactive 1:1 intermediate produced in the reactionbetweenisocyanides and dialkylacetylenedicarboxylates was trapped by 2,4-dihydro-3H-pyrazol-3-ones to yield highlyfunctionalized 7-oxo-1H,7H-pyrazolo[1,2-a]pyrazoles in fairly good yields.