3.4- Dihydropyrimidin-2 -ones alkoxycarbonylation

Bose, D. S., Fatima, L., Mereyala, H. B. Green Chemistry Approaches to the Synthesis of 5-Alkoxycarbonyl-4-aryl-3,4- dihydropyrimidin-2(1 H)-ones by a Three-Component Coupling of One-Pot Condensation Reaction Comparison of Ethanol, Water, and Solvent-free Conditions. J. Org. Chem. 2003, 68, 587-590. 

Hu, E. H., Sidler, D. R. and Dolling, U. H. 1998. Unprecedented catalytic three component one-pot condensation reaction An efficient synthesis of 5-alkoxycarbonyl-4-aryl-3,4-dihydropyrimidin-2(17/)-ones. J. Org. Chem. 63(10) 3454-3457. 

Bose DS, Fatima L, Mereyala HB (2003) Green chemistry approaches to the synthesis of 5-alkoxycarbonyl-4-aryl-3,4-dihydropyrimidin-2(l.ff)-ones by a three-component coupling of one-pot condensation reaction comparison of ethanol, water, and solvent-free conditions. 

Zlotin et al. [240] reported the S57nthesis of 3,4-dihydropyrimidin-2-(lH)-ones 139 140 by condensation between 2-arylidenes and 0-methylisourea sulfate using [BMIM][Bp4] in a molar ratio of 1 0.2 (reactant/IL) (Scheme 79). The authors proposed a partial isomerization of first step products in the presence of NaHCOs and [BMIM][Bp4] [241]. Pur-ther transformation into the corresponding 139 was taken place by regjoselective N-alkoxycarbonylation and 0-demeth-ylation. The same reaction when carried out in DMP in die presence of K2CO3 as a base, tire products formation took place only after 16h at room temperature. This established the improvement made by IL in tire course of reaction. 

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