Fabrication of HPA-ZSM-5 and their successful application to the recyclable heterogeneous catalyst for the smooth synthesis of spiro-pyrido-pyrimidine indoline derivatives

A beneficial and efficient one-pot three-component approach for the synthesis ofspiro cyclic 2-oxindole derivatives have been described by the reaction of isatins,cyclic-1,3-diketones and 6-amino-1,3-dimethyluracil in the presence of highlyactive HPA-ZSM-5 microporous catalyst. The zeolite catalyst has been synthesizedand the catalyst has been thoroughly characterized by X-ray diffraction (XRD),field emission scanning electronic microscopy (FE-SEM), Fourier transforminfrared (FT-IR), energy dispersive spectroscopy (EDS) and N2-adsorption analysis.HPA-ZSM-5 catalyst exhibited exceptional recyclability at least for 6 times andthe surface acidity was not significantly changed. The best results were gainedin H2O and we found the convincing results in the synthesis of spiro-pyridopyrimidinein the presence of HPA-ZSM-5 (10 mg) under ultrasound irradiation(40W). Experimental simplicity, wide range of products, excellent yields in shortreaction times and low catalyst loading are some of the substantial features ofthis procedure. The present catalytic method is extensible to a wide diversity ofsubstrates for the synthesis of a variety-oriented library of spiro-pyrido-pyrimidineindoline derivatives.