Silica tungstic acid as an efficient and reusable catalyst for the one-pot synthesis of 2-amino-4H-chromene derivatives.

Silica tungstic acid (STA) has been found to be an efficient and reusable solid acid catalyst for the synthesis of 2-amino-4H-chromenes via the three-component reaction of aromatic aldehydes, malononitrile, and ß-naphthol. STA as a novel solid acid was characterized by X-ray fluorescence, X-ray diffraction, and Fourier transform infrared spectroscopy.