Abstract
Indole‐2,3‐dione (1) was treated with malonic acid (2) in a mixture of ethanol/pyridine to afford 1‐[3‐(2‐oxoindolinylidene)]acetic acid (3). Compound 3 reacted with thionyl chloride to give the corresponding acid chloride (4). The acid chloride 4 reacted with arenes in the presence of AlCl~3~ to yield 3‐(2‐oxoindolinylidene)acetophenones 5a–c. Compounds 5a–c reacted with 3‐methylpyrazolin‐5‐one derivatives 6a,b to give 3‐aracyl‐3‐[4′‐(3′‐methylpyrazolin‐5‐onyl)]‐indoline‐2‐one derivatives 7a–f. Compounds 7a–f were treated with phosphorus pentoxide in phosphoric acid, with ammonium acetate or methanolic methylamine and with phosphorus pentasulfide to give spiro[indoline‐3,4′‐(pyrazolo[4,5‐b]pyran)]‐2‐ones 8a–f, spiro[indoline‐3,4′‐(pyrazolo[4,5‐b]‐dihydropyridine)]‐2‐ones 9a–f, 10a–f and spiro[indoline‐3,4′‐(pyrazolo[4,5‐b]thiopyran)]‐2‐ones 10a–f, respectively. All of the synthesized spiroheterocycle derivatives were identified by conventional spectroscopic methods (IR, ^1^H NMR) and elemental analyses. © John Wiley & Sons, Inc.