A concise and efficient one‐pot sequential approach for the synthesis of 5‐salicyloyl pyridine frameworks was developed from a reaction of 3‐formylchromones, malononitrile, various alcohols, and 2‐mercaptobenzimidazole as a catalyst. Malononitrile is the nitrogen source in this reaction. In this method, the variety of 2‐alkoxypyridines derivatives containing alkoxy, allyloxy, and acetylene functional groups can increase the bathochromic effect of the λ_max of pyridine to the longer wavelengths. According to experimental and theoretical investigations by the DFT method, long‐wavelength bands of 5‐salicyloyl pyridine derivatives related to the HOMO→LUMO and HOMO→LUMO+1 transitions have the π→π* nature and are caused by intramolecular charge transfer from the phenol fragment to the pyridine ring.

中文翻译：

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2-巯基苯并咪唑催化2-O-官能化-5-水杨酰基吡啶衍生物的合成

通过3-甲酰基色酮，丙二腈，各种醇和2-巯基苯并咪唑的催化反应，开发出了一种简洁高效的一锅法合成5-水杨酰基吡啶骨架的方法。丙二腈是该反应中的氮源。在该方法中，多种含烷氧基-2- alkoxypyridines衍生物，烯丙氧基和乙炔官能团可以增加的深色效果λ_最大吡啶向更长的波长。根据DFT方法的实验和理论研究，与HOMO→LUMO和HOMO→LUMO + 1跃迁相关的5-水杨酰基吡啶衍生物的长波带具有π → π*性质是由分子内电荷从酚片段转移至吡啶环引起的。