In this paper, a modified and facile Gewald reaction triggered by sodium polysulfide in the absence of catalytic base was developed. This approach involves a one-pot ultrasound- irritated aqueous reaction between ketones or aldehydes, malononitrile, and sodium polysulfide, which are converted into the corresponding 2-aminothiophene derivatives in moderate to high yields. In comparison with conventional methods, the prominent features ...
