SYNTHESIS AND CHARACTERIZATION OF E/Z-4,5-DIHYDRO SPIRO [3- PHENYL-5-SUBSTITUTED PHENYL ISOXAZOLE-4,4'(2',4'-DIHYDRO-5'- METHYL-2'-PHENYL/PHENYLMETHYL-3'H-PYRAZOL-3'-ONES)]

4-Arylmethylene-2,4-dihydro-2,5-disubstituted-3H-pyrazol-3-ones (1a-f; as dipolarophile) react with benzonitrile oxide(2; as 1-3 dipole) to yield E/Z-4,5-dihydro spiro-[3-phenyl-5-substituted phenyl isoxazole-4 ,4'(2',4'-dihydro-5'-methyl-2'-phenyl/phenyl methyl-3'H- pyrazol-3'-ones)]. 1, 3-Dipolar cycloaddition reactions have been studied in numerous unsaturated systems leading to five-membered ring heterocycles. 1-3,4-Arylmethylene-2,4-dihydro-2,5-disubstituted-3H-pyrazol-3-one (as dipolarophile) reacted with diphenyl nitrile imine (as 1,3-dipole) to yield two isomers VIZ. E and Z-4,5-dihydro spiro-[4-aryl-1,3-diphenyl pyrazole-5,4'-(2'4'-dihydro-2'5'-disubstituted -3'H-pyrazol-3'-ones)] 1,3-dipolar cycloaddition reaction of 4-arylmethylene-2,4-dihydro-5-methyl-2-phenyl/phenylmethyl-3H-pyrazol-3-ones (1a-f; as dipolarophile) with benzonitrile oxide (2,as 1,3-dipole) resulted in the formation of E/Z-4,5-dihydro spiro-[3-phenyl-5-substituted-phenyl isoxazole-4,4'-(2',4'-dihydro-5'methyl-2'-phenyl/phenylmethyl-3'-H-pyrazole-3 one)] (3)(scheme-1).I-VIII This reaction is stereospecific as well as stereoselective and the peculiarity of the reaction commanded interest & stimulated to undertake the synthetic process. The benzonitrile oxide (2) is generated in situ by the reaction of benzhydroxamoyl chloride and triethylamine in the presence of dry chloroform at the room temperature. The physical and spectral data of the compounds are presented (Table 1).IX-XXII