An efficient synthesis of 4-substituted pyrazolone derivatives was developed. 4-Substituted pyrazolone derivatives were synthesized in 78–97% yields starting from various 3-substituted isoxazole-5-carbaldehydes, ethyl acetoacetate and hydrazine under microwave irradiation and solvent-free conditions, and were characterized by HRMS, FTIR, ¹H NMR and ¹³C NMR spectroscopy. SiO₂ was found to possess favorable catalytic activity and dispersancy for the condensation reaction. The merits of this method include the environmentally friendly reaction conditions, simple operation, broad substrate, satisfied yields and the reuse of the silica. Moreover, the crystal structure of the compound 2-(4-chlorophenyl)-4-((1-(4-chlorophenyl)-5-hydroxy-3-methyl-1H-pyrazol-4-yl)(3-phenylisoxazol-5-yl)methyl)-5-methyl-1H-pyrazol-3(2H)-one (5a) in the monoclinic space group C2/c was presented.

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快速高效的无溶剂微波辅助合成含取代异恶唑环的吡唑啉酮衍生物

开发了4-取代的吡唑啉酮衍生物的有效合成方法。在微波辐射和无溶剂条件下，由各种3-取代的异恶唑-5-甲醛，乙酰乙酸乙酯和肼开始合成4-取代的吡唑啉酮衍生物，产率为78-97％，并通过HRMS，FTIR，¹ H NMR和¹³ C NMR光谱。二氧化硅₂被发现对缩合反应具有有利的催化活性和分散性。该方法的优点包括环境友好的反应条件，简单的操作，广泛的底物，令人满意的产率和二氧化硅的再利用。此外，化合物2-（4-氯苯基）-4-（（1-（4-氯苯基）-5-羟基-3-甲基-1H-吡唑-4-基）（3-苯基异恶唑-5）的晶体结构提出了单斜空间群C2 / c中的（yl）甲基）-5-甲基-1H-吡唑-3（2H）-一（5a）。