One-pot, three-component, catalyst-free synthesis of novel derivatives of pyrido-[2,3-<i>d</i>]pyrimidines under ultrasonic irradiations

<p>Novel derivatives of pyrido-[2,3-<i>d</i>] pyrimidines were synthesized via an efficient and catalyst- free, one-pot, three-component reaction of 3-(1-methyl-<i>1H</i>-pyrrol-2-yl)-3-oxopropanenitrile, 6-amino-(ethylthio)pyrimidine-4(<i>3H</i>)-one, and arylaldehydes under ultrasonic irradiations. This practical method furnished the desired pyridopyrimidines in high yields (79–89%) and short reaction times (25–40 min).</p>