Synthesis of Substituted dihtydro-5H-pyrano[4,-3-b]pyridin-3-carboxamides and -3-carboxylic acids
Optimal conditions were established for the hydrolysis of 2-amino-3-cyanodihydropyranopyridines to give substituted dihydro-5H-pyrano-[4,3-b]pyridine-3-carboxylic acids. Two convenient routes also were developed for the synthesis of the 3-carboxamide derivatives of substi-tuted dihydro-5H-pyrano[4,3-b]pyridine from the corresponding 2-chlorocyano derivatives.