Polyethylene glycol (PEG-400): a mild and efficient reaction medium for one-pot synthesis of 3-hydroxy-3-(pyridin-2-ylmethyl)indolin-2-ones

3-(Pyridylmethyl)-3-hydroxy-2-oxindole derivatives were synthesized in high yields under mild, and catalyst-free conditions using polyethylene glycol (PEG-400) as a solvent. The use of low cost PEG-400 makes it simple, convenient, and environmentally benign.