Solvent free one-pot multi-component synthesis of 3,4-dihydropyrimidin-2(1H)-ones catalyzed by ZnFe2O4 magnetic nanoparticles as an environmentally friendly, cheap, and effective catalyst

Recently, interest in the synthesis of 3,4-dihydropyrimidin-2-(1H)-ones (Biginelli compounds) and their derivatives has increased tremendously because of their diverse therapeutic and pharmacological properties such as antiviral, antibacterial, antitumour and antihypertensive activities. Some have been successfully used as calcium channel blockers, α-1a-antagonists and neuropeptide Y (NPY) antagonists. Several alkaloids which contain the dihydropyrimidine core unit have been isolated from marine sources. Most notable among these are the batzelladine alkaloids, which were found to be potent HIV gp-120-CD4 inhibitors. The Biginelli reaction is considered as an important multi-component reaction for generating compounds with diverse medicinal applications [1-3]. In the present work, a green and efficient method is described for the solvent free synthesis of 3,4-dihydropyrimidin-2(1H)-ones through one-pot three-component condensation of ethyl acetoacetate, an aryl aldehyde, and urea in the presence of ZnFe2O4 nanoparticles as high-performance magnetic catalyst (scheme 1). The present methodology offers several advantages such as high yields, relatively short reaction times, mild reaction condition, easy work up, and using a highly recyclable catalyst.