Synthesis of isoxazolo[3,4-b]pyridin-3(1H)-one and isoxazolo[5,4-b]-pyridin-3(2H)-one

Abstract

α-(N′-Hydroxyamidino)acetohydroxamic acid (I) and 5-aminoisoxazol-3(2H)-one (V) were each condensed with acetylacetone to yield 2-hydroxyamino-4,6-dimethylpyridine-3-carboxylic acid (II) and 4,6-dimethyl-isoxazolo[5,4-b]pyridin-3(2H)-one (VIa) respectively. Compound (II) gave isoxazolo[3,4-b]pyridin-3(1H)-ones (III) on acetylation, benzoylation, and bromination. The structures of (II) and (VIa) were confirmed by their conversion into known products.