An efficient four-component synthesis of benzopyranopyridines is described by one-pot condensation of salicylaldehydes, thiols and 2 equiv of malononitrile with nano-PbWO4 as a robust and reusableheterogeneous catalyst under ultrasonic irradiation. Lead tungstate (PbWO4) nanostructures have been synthesized via a sonochemical method based on the reaction between lead (II) nitrate and sodium tungstate dihydrate in an […]