Methods for the Synthesis of 4-Pyrazolyl- and 4-Pyridyl-5-oxo-1,4,5,7-tetrahydrofuropyridines

Article abstract of DOI:10.1007/BF01170746

The most suitable method for the synthesis of 4-pyrazolyl- or 4-pyridyl-5-oxo-1,4,5,7-tetrahydrofuro<3,4-b>pyridines uses 4-chloro- or 4-acetoxyacetoacetic esters in various versions of the Hantsch synthesis with closure of a lactone ring during the reaction.Some of the intermediate products (2-chloromethyl- and 2-acetoxymethyl-1,4-dihydropyridines) were isolated.Cyclization with the formation of lactones does not occur in N-substituted 1,4-dihydropyridines.