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<p>Due to the issues of the acid-catalyzed three-component synthesis of pyrazolo[3,4-b] quinolinones (PQs) from 3-amino-pyrazole, a novel base-catalyzed four-component synthesis of PQs using the economic precursors and magnetic alkaline nanocellulose (ANC) is introduced. So, ANC was firstly prepared, characterized, and magnetized by stable magnetic phase <i>γ</i>-Fe<sub>2</sub>O<sub>3</sub> as the core–shell nanocatalyst <i>γ</i>-Fe<sub>2</sub>O<sub>3</sub>@ANC. With the mean size particles ~ 35&#xa0;nm, the titration basicity of 7.0&#xa0;mmol HO<sup>−</sup>/g, and organic: inorganic ratio 18:82, the core–shell catalyst <i>γ</i>-Fe<sub>2</sub>O<sub>3</sub>@ANC was applied in the novel four-component synthesis of PQs. Thus, base-catalyzed condensation of 3-methylpyrazolones with ammonium acetate, dimedone, and aryl aldehydes yielded &gt; 95% of the corresponding N–H- and N-phenyl PQs. With a 100% chemoselectivity for 3-methyl-1H-pyrazolone than 1-phenyl ones, TON 1314.22–1385.71, and TOF 20.88–138.57h<sup>−1</sup> this versatile protocol provides an atom-economical (73%) approach to quantitative rapid synthesis of N–H- and N-phenyl PQs. Biocompatibility, simple catalyst reusability, catalytic efficiency, accessible low-price starting materials, wide substrate scope, scalability, and high chemoselectivity are significant advantages of this method.</p>

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A nano-cellulose-based and core–shell catalyst for the improved chemo-selective synthesis of pyrazolo[3,4-b] quinolinones

  • 期刊论文

  • 发表日期：

    2026年4月21日

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  • Fatemeh Tamaddon,
  • Ehsan Ahmadi-AhmadAbadi,
  • Negin Amanat-Yazdi

摘要

Due to the issues of the acid-catalyzed three-component synthesis of pyrazolo[3,4-b] quinolinones (PQs) from 3-amino-pyrazole, a novel base-catalyzed four-component synthesis of PQs using the economic precursors and magnetic alkaline nanocellulose (ANC) is introduced. So, ANC was firstly prepared, characterized, and magnetized by stable magnetic phase γ-Fe2O3 as the core–shell nanocatalyst γ-Fe2O3@ANC. With the mean size particles ~ 35 nm, the titration basicity of 7.0 mmol HO−/g, and organic: inorganic ratio 18:82, the core–shell catalyst γ-Fe2O3@ANC was applied in the novel four-component synthesis of PQs. Thus, base-catalyzed condensation of 3-methylpyrazolones with ammonium acetate, dimedone, and aryl aldehydes yielded > 95% of the corresponding N–H- and N-phenyl PQs. With a 100% chemoselectivity for 3-methyl-1H-pyrazolone than 1-phenyl ones, TON 1314.22–1385.71, and TOF 20.88–138.57h−1 this versatile protocol provides an atom-economical (73%) approach to quantitative rapid synthesis of N–H- and N-phenyl PQs. Biocompatibility, simple catalyst reusability, catalytic efficiency, accessible low-price starting materials, wide substrate scope, scalability, and high chemoselectivity are significant advantages of this method.