Zahra Hoseini - Department of Chemistry, Mashhad Branch, Islamic Azad University, Mashhad, Iran
Abdolghasem Davoodnia - Department of Chemistry, Mashhad Branch, Islamic Azad University, Mashhad, Iran
Mehdi Pordel - Department of Chemistry, Mashhad Branch, Islamic Azad University, Mashhad, Iran

In this work, the newly prepared functionalized graphene oxide (GO), denoted as GO-SiC3-NH3-H2PW, was found as an effective nanocatalyst for a one-pot reaction of dimedone, aryl aldehydes, and malononitrile, giving rise to tetrahydrobenzo[b]pyran derivatives. The reactions were conducted in water, giving the corresponding products in 88-98% yields over 4-15 min. Other advantages of the method include cheap catalyst, easy work-up, absence of any dangerous solvents and the catalyst's reusability for up to five consecutive runs (97, 96, 95, 95, and 94 in first to fifth use, respectively).

Tetrahydrobenzo[b]pyran, H3PW12O40, functionalized graphene oxide