6- And 7-Substituted 4H-Pyrido[1,2-a] pyrimidin-4-ones. Synthesis via the Acid-catalyzed Isomerization of 2-(Acetoacetamido)pyridines |
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Authors: | Harry L. Yale E. R. Spitzmiller |
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Abstract: | A novel procedure has been developed for converting a variety of substituted 2-(aceto-acetamido)pyridines into substituted 4H-pyrido[1,2-a]pyrimidin-4-ones. The reaction involves an acid-catalyzed isomerization of the 2-(acetoacetamido)pyridine derivatives into the corresponding enamines, under conditions that permit the latter to undergo cyclization to the 4-one, in situ. The method has been employed to prepare a number of hitherto unknown 2,6- and 2,7-di- and 2,7,9-trisubstituted 4H-pyrido[1,2-a]pyrimidin-4-ones. |
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