Studies on Ketene and its Derivatives. VI. Reaction of Diketene with Aminopyridines and their N-Oxides

Abstract

Reaction of diketene with three of aminopyridine and their N-oxides was examined. 2-Aminopyridine (I) afforded its acetoacetate (II) and 2-methyl-4H-pyrido[1, 2-a]pyrimidin-4-one (III) as a by-product. N-oxide of I (V) afforded its acetoacetate (VI) and 2-[(6-acetoacetomido-2-pyridyl)methyl]-6-methyl-4H-pyran-4-one (VII). 3-Amino isomers (VIII and XI) underwent their acetoacetates (VII and XVIII) respectively. Although 4-aminopyridine 1-oxide (XIV) did not react with diketene, 4-aminopyridine (XVI) afforded 1-(4-pyridyl-3-acetyl-6-methyl-2, 4-(1H, 3H)-pyridinedione (XVII).