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• 141-97-9 ethyl acetoacetate 
• 52287-68-0 N-[(4-methylphenyl)(tosyl)methyl]urea 
• 299949-24-9 ethyl 6-methyl-2-oxo-4-p-tolyl-1,2,3,4-tetrahydropyrimidine-5-carboxylate 
• 104-87-0 4-methyl-benzaldehyde 
• 57-13-6 urea 

Relevant academic research and scientific papers

Towards Enzyme-like, Sustainable Catalysis: Switchable, Highly Efficient Asymmetric Synthesis of Enantiopure Biginelli Dihydropyrimidinones or Hexahydropyrimidinones

Organocatalysts displaying a network of cooperative hydrogen bonds (NCHB) have been employed in an enzyme-like manner for a direct, switchable synthesis of enantiopure hexahydropyrimidinones (HHPMs) or dihydropyrimidinones (DHPMs), which starts at a common, easily accessible α-ureidosulfone stage. The NCHB organocatalyst exploits all its potential as a pure hydrogen-bond biomimetic catalyst even in the presence of organic bases. This one-pot, diastereo- and enantioselective synthetic procedure has been proven to be robust, scalable, highly efficient, and environmentally benign. A straightforward and truly practical entry to enantiopure HHPMs is reported for the first time.

Solution-phase synthesis and evaluation of tetraproline chiral stationary phases

A protocol was developed for the solution-phase synthesis of multigram amounts of two 9-fluorenylmethoxycarbonyl (Fmoc)-protected tetraproline peptides. These tetraproline peptides were then attached to amino derivatized silica gel. The replacement of the Fmoc group with the trimethylacetyl group lead to two tetraproline chiral stationary phases (CSPs). A comparison of the chromatographic behavior of these two solution-phase-synthesized tetraproline CSPs with that prepared by stepwise solid-phase synthesis revealed that all three had similar chromatographic performance for resolving 53 model analytes. This suggests that the solution-phase synthesis of oligoprolines, which allows for the specific benefits of good batch reproducibility, selector homogeneity, and possibly low cost, is a feasible alternative to the solid-phase synthesis of oligoproline CSPs. Copyright

Highly enantioselective Biginelli reaction catalyzed by a simple chiral primary amine catalyst: Asymmetric synthesis of dihydropyrimidines

Several chiral primary amines were introduced as organocatalysts for the asymmetric Biginelli reaction. The reaction was performed by using a combined catalyst consisting of a chiral bifunctional primary amine-pyridine 5j and hydrochloric acid in a mixed

Bifunctional primary amine-thiourea-TfOH (BPAT·TfOH) as a chiral phase-transfer catalyst: The asymmetric synthesis of dihydropyrimidines

An enantioselective Biginelli reaction has been developed by using a bifunctional primary amine-thiourea-TfOH (BPAT·TfOH) as a chiral phase-transfer catalyst and t-BuNH2·TFA as an additive in saturated brine at room temperature. The correspondi

Enantioselective organocatalytic Biginelli reaction: Dependence of the catalyst on sterics, hydrogen bonding, and reinforced chirality

From a systematic investigation involving the synthesis of a series of catalysts and screening studies, the organocatalyst 16, which is sterically hindered, contains a strong hydrogen-bonding site, and is endowed with reinforced chirality, is shown to pro

Primary amine catalyzed Biginelli reaction for the enantioselective synthesis of 3,4-dihydropyrimidin-2(1H)-ones

Several chiral primary amines, mainly those derived from cinchona alkaloids, were evaluated as organocatalysts for the asymmetric Biginelli reaction. With quinine-derived amine catalyst 1 and after extensive optimization of the reaction conditions, 3,4-di

Cooperative and enantioselective NbCl5/primary amine catalyzed Biginelli reaction

A series of chiral organocatalysts and Lewis acids have been evaluated in the Lewis acid/organocatalysts-based cooperative catalytic Biginelli reaction, which resulted in the determination of a novel cooperative Lewis acid/primary amine catalyst system, N

Highly enantioselective Biginelli reaction promoted by chiral bifunctional primary amine-thiourea catalysts: Asymmetric synthesis of dihydropyrimidines

The diastereospecific formation of dihydropyrimidines (DHPMs) has been achieved in moderate to high yields with up to 99% ee by a Biginelli reaction. The reaction was performed by using a combined catalyst consisting of a chiral bifunctional primary amine

An enantioselective Biginelli reaction catalyzed by a simple chiral secondary amine and achiral Bronsted acid by a dual-activation route

An enantioselective Biginelli reaction that proceeds by a dual-activation route has been developed by using a combined catalyst of a readily available trans-4-hydroxyproline-derived secondary amine and a Bronsted acid. Aromatic, heteroaromatic, and fusedr