Synthetic Strategy Studies for a Concise Access to Functionalized Pyrano[4,3‐b]pyridin‐7‐ones: An Entry to Semi‐Rigid Analogs of Antihistamines

Abstract

We report short and efficient syntheses of polyfunctionalized 5,8-dihydro-7H-pyrano[4,3-b]pyridin-7-ones and 1,4dihydro-3H-pyrano[4,3-c]pyridin-3-ones which can be considered as new aza analogs of 3-isochromanones and as promising scaffolds for medicinal chemistry. Depending on the nature of the substituent, three different and complementary synthetic methodologies were used allowing the introduction of significant diversity in the substituent on the lactone ring of the pyr