2-Aminopyridine as a recyclable catalyst for metal-free synthesis of pyrano[2,3-d]pyrimidine scaffolds

This study focuses on the synthesis of pyrano[2,3- d ]pyrimidine structures through a one-pot process without the use of metals. The method employs Knoevenagel-Michael cyclocondensation and utilizes a low-cost, reusable catalyst, 2-aminopyridine. The synthesis of pyrano[2,3- d ]pyrimidine structures is achieved by refluxing in ethanol (EtOH). The process allows for the easy production of compounds in large quantities and requires minimal reaction time. This cost-effective method features safe reaction conditions, avoids the need for column chromatography, facilitates easy mixing, and promotes efficient material use. Furthermore, 2-aminopyridine demonstrated excellent stability, being reusable up to four times without significant degradation. This approach is particularly beneficial for addressing environmental issues and fulfilling industrial demands. • 2-Aminopyridine as a recyclable and cost-effective catalyst • Metal-free synthesis of pyrano[2,3- d ]pyrimidine scaffolds • An environmentally friendly pathway