The thermolysis of 5-phenyl-2,3-dillydrofuran-2,3-dione in 4-methoxyphenylacetone yield 2-(4-methoxybenzyl)-2-methyl-6-phenyl-4H-1,3-dioxin-4-one via alpha-oxoketene. Reaction of 5-phenyl-2,3-dihydrofuran-2,3-dione with phenylhydrazine afforded 1,6-diphenyl-1,2-dihydropyridazine-3,4-dione. The hydrazine derivatives and 1,2-phenylenedi-. amine react with 4,4-dimethyltetrahydrofuran-2,3-dione to give the corresponding hydrazone derivatives and 3,3dimethyl-2,3-dihydrofuro[2,3-b]quinoxaline, respectively. The structures of compounds were characterized on the basis of elemental analyses, Mass, IR, H-1 and C-13 NMR spectra.