Abstract
We report the use of V, Bi and Bi-V Keggin structure where Mo is partially replaced by V, Bi, and Bi and V, respectively, in the solvent-free multicomponent synthesis of 3,4-dihydropyrimidin-2-(1H)-ones by the Biginelli method. The incorporation of V, Bi and Bi-V in the structure of PMo notably increases the catalytic activity. The following correlation between the yields of the 3,4- dihydropyrimidin-2-(1H)-ones and the number of acidic sites of the catalysts was observed: PMoBiV > PMoV > PMoBi > PMo. The reaction experiments were performed in the absence of solvent, at 80°C (1 h). Under these conditions and using the most active catalyst (PMoBiV), twelve examples were obtained with very good yields (80%–98%) and high selectivity. The catalyst was easily recycled and reused without appreciable loss of its catalytic activity. The synthetic method presented is a simple, clean and environmentally friendly alternative for the obtention of substituted 3,4-dihydropyrimidin-2-(1H)-ones.
Keywords: 3, 4-Dihydropyrimidin-2-(1H)-ones, Biginelli reaction, Modified keggin heteropolyacids, Solvent-free synthesis.
Call for Papers in Thematic Issues
Catalytic C-H bond activation as a tool for functionalization of heterocycles
The major topic is the functionalization of heterocycles through catalyzed C-H bond activation. The strategies based on C-H activation not only provide straightforward formation of C-C or C-X bonds but, more importantly, allow for the avoidance of pre-functionalization of one or two of the cross-coupling partners. The beneficial impact of ...read more
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