Synthesis of Some New Fused Heterocyclic Rings Derived from 3-Benzofuranone

In the present work, the synthesis of some new fused heterocyclic rings derived from 3-benzofuranone was achieved. 3-Benzofuranone (1) was prepared by the action of polyphosphoric acid on phenoxyacetic acid. 3-Benzofuranone was treated with benzaldehyde and furfural in alkaline medium to afford 2-arylidene-3-benzofuranone (aurones) (2, 3). The reactions of the synthesized aurones with hydrazine hydrate, phenyl hydrazine, hydroxylamine hydrochloride, acetamide, urea and thiourea gave substituted pyrazoline (4, 5), 3-phenyl pyrazoline (6, 7), isoxazole (8, 9), 2-pyridinone and pyrimidin-2-one(thione) (12-15) respectively fused with 3-benzofuran. The structures of the synthesized compounds were confirmed by IR and physical methods.