“Arylidene oxazolones as building blocks of some heterocycles of anticipated biological activity

Abstract

Summary Comparison study between the reactivity of 1,3-oxa-zolones bearing phenylmethylene- and/or 1,3-diphenyl-pyrazolylmethylene- groups at position-4 towards methyl 4-aminobenzoateandhydrazine hydrate was studied. Fusion of oxazolones4-phenylmethylene-2-phenyl-1,3-oxazole-5(4H)-one 29 and 4-((1,3-diphenyl-1H-pyra-zol-4-yl)methylene)-2-phenyl-1,3-oxazole-5(4H)-one34 with methyl4-aminobenzoate on anoil bath gave the imid-azolone derivatives 227aand227b,respectively.Refluxing 227a withhydrazine hydrate in methanol for 3h, gave the acid hydrazide derivative 228a;as E-configuratedisomer with a better yield together with a compound which was identical in all respects (m.p., mm.p. and TLC) with methyl4-aminobenzoate. While the treatment of the imidazolone227b with hydrazine hydrate indioxane for 20h, gave the triazinone derivative 229(Scheme 1).