An efficient and green reaction of isatins, 3-amino-1-phenyl-2-pyrazolin-5-one (3-amine-1 H -pyrazole), and β -diketone in aqueous medium

n efficient and green reaction of isatins, 3-amino-1-phenyl-2-pyrazolin-5-one (3-amine-1 H -pyrazole), and β -diketone in aqueous medium in the presence of PEG – SO_3H is reported, and a series of novel spirocompounds was obtained with high yields. The advantages of this reaction were simple procedure, moderate reaction conditions, and wide range of substrates. More importantly, the catalyst PEG – SO_3H could be recovered for reuse up to five times. Graphical Abstract