Thermal and photochemical reaction of isoxazolone with indole-2,3-dione derivatives

The reaction of indole-2,3-dione derivatives with five membered heterocycle , viz isoxazolone under thermal as well as photochemical conditions is desc ribed. While under refluxing ethanol these conditions afforded 2,3-dihydro- 3-(5'-oxo-3'-phenylisoxazolidyl)indol-2-one 3 and a spiro product 2',3'-dih ydro-3,7diphenylspiro[diisoxazolo[4,5-e:4,5-b]pyran-8,3'-indol]2'-one 4, th e uv light induced irradiation mainly produced 4,5-dioxo-3-phenylisoxazolo[ 5,4-b][1]benzazepine 5 and 3-phenylisoxazolo[5,4-b]quinoline-4-carboxylic a cid 6. The products have been characterised on the basis of spectral data a nd elemental analyses.