2,1-Benzisoxazoles have been selectively synthesized through reductive heterocyclization of 2-nitroacylarenes using Pt-supported nanoparticles. The reaction involves a cascade process in which the first step is the reduction of the nitro group into hydroxylamine followed by heterocyclization through the nucleophilic attack of the hydroxylamine group to the carbonyl of the acyl group and further dehydration. The reaction was performed on Pt/C, Pt/TiO₂, and Pt/MgO using hydrogen as the reducing agent under mild reaction conditions. The results showed that Pt/MgO was the most active and selective catalyst. The study of the influence of the crystal size of the metal on the activity and selectivity, combined with the reaction mechanism examined by in situ Fourier transform infrared spectroscopy of the adsorbed reactant, showed that the maximum activity and selectivity to the target compound can be achieved by controlling the architecture of metal particles and acid–base properties of the support. The effect of temperature on selectivity, the stability of the Pt/MgO catalyst, and the scope of the reaction have been studied. Finally, reductive heterocyclization using different metals (Pd and Au) supported on MgO has also been performed.

中文翻译：

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通过控制金属颗粒的二项式结构和载体的酸碱性质进行化学选择性还原杂环化

使用Pt负载的纳米颗粒通过2-硝基酰基芳烃的还原杂环化选择性地合成了2,1-苯并异恶唑。该反应涉及级联过程，其中第一步是将硝基还原为羟胺，然后通过羟胺基团对酰基的羰基的亲核攻击进行杂环化反应并进一步脱水。反应在Pt / C，Pt / TiO _2上进行，在温和的反应条件下使用氢作为还原剂的Pt / MgO。结果表明，Pt / MgO是最具活性和选择性的催化剂。研究金属晶体尺寸对活性和选择性的影响，并结合原位傅里叶变换红外光谱法对吸附的反应物进行研究，发现可以实现对目标化合物的最大活性和选择性。通过控制金属颗粒的结构和载体的酸碱性质。研究了温度对选择性，Pt / MgO催化剂稳定性和反应范围的影响。最后，还进行了使用负载在MgO上的不同金属（Pd和Au）的还原性杂环化反应。