A facile one-pot three component synthesis of 3, 4-dihydropyrimidin-2(1H)-ones or thiones promoted by a polymer-supported BF3 under solvent-free conditions

In this study, cross-linked poly(4-vinylpyridine)-supported boron trifluoride, [P-4-VP]-BF3, has been easily prepared and characterized by Fourier transform infrared (FT-IR), X-ray diffraction pattern, energy-dispersive X-ray spectroscopy analysis, scanning electron microscopy images and mapping. Afterward, catalytic activity of the obtained solid polymer-supported Lewis acid catalyst has been examined in Biginelli reaction for the synthesis of 3, 4-dihydropyrimidin-2(1H)-ones and 3, 4 dihydropyrimidin-2(1H)-thiones via one-pot three-component reaction between aryl aldehydes, beta-dicarbonyl compounds and urea or thiourea under solvent-free conditions. The products were confirmed by their melting points (m.p.), FT-IR H-1 and C-13 nuclear magnetic resonance spectroscopy. The present procedure offers advantages, such as high to excellent yield (68-97% isolated yields), short reaction time (30-45 min), reusability of the catalyst, clean and fast work-up and easy separation of the catalyst by a simple filtration. [GRAPHICS] .

Automated summary

In this study, a cross-linked poly(4-vinylpyridine)-supported boron trifluoride catalyst was prepared and characterized. The catalyst showed good catalytic activity in the Biginelli reaction under solvent-free conditions, with advantages such as high yield, short reaction time, and reusability.