Efficient synthesis of pyrimidinone derivatives by ytterbium chloride catalyzed Biginelli-type reaction under solvent-free conditions

An Efficient and Environmentally Friendly Procedure for the Synthesis of Some Novel 8-Benzylidene-4-phenyl-3,4,5,6,7,8-hexahydro-1H-quinazolin-2-ones/thiones using Tetrabutylammonium Hexatungstate as a Reusable Heterogeneous Catalyst under Solvent-Free Conditions

“…Corresponding contrastive reactions were performed and the results indicated that whichever of the cyclohexanone or urea was used at double the equivalent, respectively, the yields were appreciably improved ( Table 2, Entries 3 and 4). Although the reasons for this conversion are not clear but in confirmation of reported literatures 18 and according to our experimentally observations, the best yield in the shortest reaction time was obtained using the molar ratio of 1:1:1.2 of benzaldehyde, cyclohexanone and urea respectively.…”

Synthesis of arylidene dihydropyrimidinones and thiones catalyzed by iron (III) phosphate

“…6,7 More useful procedures are three-component condensation with aromatic aldehydes, cyclopentanone, and urea or thiourea in presence of stoichiometric amounts of TMSCl 8 and YbCl3. 9 Therefore, we wish to report the synthesis of arylidene heterobicyclicpyrimidinones and thiones using FePO4 10,11 in the presence of arylaldehydes, cyclopentanone, and urea or thiourea. Moreover, this approach is known as an important economical and environmentally benign process in synthesis chemistry, because it decreases the number of reaction steps, energy consumption and waste (Scheme 1).…”

Ethyl (E)-4-(2,4-Dimethoxyphenyl)-6-(2,4-dimethoxystyryl)-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate

“…Although this reaction normally produces DHPM derivatives, there are similar reactions, usually called Biginelli-type reactions, that produce different pyrimidine derivatives, such as spiropyrimidinone [3,4] and arylidinepyrimidinone [5][6][7][8][9][10][11].…”

“…Despite the similarity of its reaction pattern to the Biginelli-type reaction producing arylidenepyrimidinone, there is a difference in the carbonyl component used. The aforementioned Biginelli-type reaction uses a cyclic mono carbonyl component that has two kinds of acidic C-H with equivalent reactivity, such as cyclopentanone [5][6][7][8][9][10], cyclohexanone [9][10][11] and cyclooctanone [9], so that it yields a bicyclic arylidenepyrimidinone. Interestingly, in our experiment, we used an acyclic 1,3-dicarbonyl component that possessed two acidic C-H moieties with different reactivities, namely ethyl acetoacetate.…”