A reported two-step procedure for preparing dimethyl 4-oxo-4H-pyran-3,5-dicarboxylate was extensively optimized. It was found that the reactions can be carried out in toluene as a single solvent and the product was directly obtained by a simple filtration. More importantly, considering potential solvent recovering and recycling, the effluent of the process can be remarkably reduced. This new process facilitated the potential scale-up with commercial significance.

中文翻译：

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4-Oxo-4 H-吡喃-3,5-二羧酸二甲酯的合成工艺改进

广泛地优化了报道的用于制备4-氧代-4 H-吡喃-3，5-二羧酸二甲酯的两步程序。发现反应可以在甲苯中作为单一溶剂进行，并且产物通过简单过滤直接获得。更重要的是，考虑到潜在的溶剂回收和再循环，可以显着减少该过程的流出物。这一新过程促进了具有商业意义的潜在规模扩大。