Abstract

A heterogeneous organic–inorganic hybrid durable nanocatalyst γ-Al₂O₃@Silane-TMG was prepared by covalently functionalization of nano-γ-Al₂O₃ through anchored 3-chloropropyl- trimethoxysilane with 1,1,3,3-tetramethylguanidine (TMG). The structure of the catalyst was characterized by various techniques including FT-IR, XRD, SEM, EDX and TGA analyses. The synthesized nanocatalyst was successfully used in an efficient and green four-component synthesis of pyrazolopyranopyrimidine derivatives using ethyl acetoacetate, hydrazine hydrate, arylaldehydes and barbituric acid (or thiobarbituric acid) in H₂O at 40 ºC. This practical method produced the desired products at reduced reaction times (10–25 min) and high to excellent yields (85–98%). The main advantages of this practical method are the use of heterogeneous basic nanocatalyst, simple work-up procedure with no need to chromatographic purification, affording highly selective conversion and recyclability of the catalyst which could be used in 5 cycles with only a small decrease in its activity.

Graphic abstract

中文翻译：

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四甲基胍官能化的纳米γ-Al2 O 3作为吡唑并吡喃并嘧啶衍生物四组分合成的新型高效催化剂

摘要

异构有机-无机混合耐用纳米催化剂的γ-Al ₂ ö ₃ @硅烷TMG物通过共价官能化制备纳米的γ-Al ₂ ö ₃通过锚定的3-氯丙基三甲氧基硅烷与1,1,3,3-四甲基胍（ TMG）。催化剂的结构通过多种技术进行表征，包括FT-IR，XRD，SEM，EDX和TGA分析。所合成的纳米催化剂已成功用于H _2中使用乙酰乙酸乙酯，水合肼，芳醛和巴比妥酸（或硫代巴比妥酸）的高效，绿色四组分合成吡唑并吡喃并嘧啶衍生物。O在40ºC下。这种实用的方法以减少的反应时间（10–25分钟）和高至优异的产率（85–98％）生产了所需的产品。该实用方法的主要优点是使用非均相碱性纳米催化剂，无需色谱纯化即可进行简单的后处理程序，提供了高度选择性的转化和可循环利用的催化剂，该催化剂可在5个循环中使用，但其使用量仅略有减少活动。

图形摘要