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Unusual direction of the C–H arylation of 2-(het)aryl[1,2,4]triazolo[1,5-a]pyrimidines with (het)aryl halides under catalysis by ruthenium(II) complexes has been revealed. The reaction involved activation of the C7–H bond rather than the Cα–H bond of the (het)aryl substituent at C2 of the triazolopyrimidine core. The arylation of 2-substituted [1,2,4]triazolo[1,5-a]pyrimidines with (het)aryl bromides afforded a series of 7-(het)aryl derivatives in good yields. [ABSTRACT FROM AUTHOR]

The use of new 7-methylazolo[1,5-a]pyrimidine-6-carbonitriles for the construction of heterocyclic systems annulated at the pyrimidine ring has been demonstrated. Cascade cyclizations are carried out via the intermediate dimethylaminovinyl derivatives. The specific features of the cascade reactions with ammonia or aliphatic amines as N1 synthons, depending on the reaction conditions, are demonstrated. [ABSTRACT FROM AUTHOR]

The design, synthesis, and biological screening of novel 4-aryl-6-[6-(2,4-dichlorophenyl)-2-methyl-pyridin-3-yl]-3,4-dihydropyrimidine-2(1H)-thiones and 2′-amino-6′-aryl-6-(2,4-dichlorophenyl)-2-methyl[3,4′-bipyridine]-3′-carbonitriles are described. The reaction involves Claisen–Schmidt condensation to afford the target compounds in up to 93% yield. The synthesized compounds were characterized by using FT-IR, 1H NMR, 13C NMR, mass spectrometry, and elemental analysis and were screened for their antibacterial activity against both gram-negative and gram-positive bacterial strains. Methoxy-, hydroxy-, and halogen-substituted deriva-tives showed good inhibitory effect against the tested microorganisms. Also, some of the compounds showed better anti-inflammatory activity when compared to the standards. The electron-donor properties of the novel pyrimidine derivatives were confirmed by quantum chemical studies. [ABSTRACT FROM AUTHOR]

The reaction 5-(arylmethylidene)-2,4,6-pyrimidine-2,4,6(1H,3H,5H)-triones with isoquinoline and dimethyl but-2-ynedioate gave cycloaddition products, mixtures of diastereoisomeric substituted dimethyl 2-aryl-2′,4′,6′-trioxo-1′,3′,4′,6′-tetrahydro-2H,2′H,11bH-spiro[pyrido[2,1-a]isoquinoline-1,5′-pyrimidine]-3,4-dicarboxylates which were converted to the corresponding dipotassium salts by treatment with excess potassium hydroxide in ethanol. The synthesized compounds are of interest as promising intermediate products with potential antitubercular and fungicidal activities. [ABSTRACT FROM AUTHOR]

3-Aroylpyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones reacted with 6-amino-1,3-dimethylpyrimidine-2,4(1H,3H)-diones to give 3-aroyl-4-hydroxy-1-(2-hydroxyaryl)-1′,3′-dimethylspiro[pyrrole-2,5′-pyrrolo-[2,3-d]pyrimidine]-2′,4′,5,6′(1H,1′H,3′H,7′H)-tetraones. The product structure was confirmed by X-ray analysis. The described reaction provides a simple route to the difficultly accessible spiro[pyrrole-2,5′-pyrrolo[2,3-d]-pyrimidine] heterocyclic system. [ABSTRACT FROM AUTHOR]

A series of new dimers of pyrimidine nucleoside analogues have been synthesized. The dimers are composed of two uracil or thymine fragments linked at N3 through a polymethylene bridge and bearing a β-D-ribofuranose residue linked to N1 of the nucleobase through a 1,2,3-triazolylalkyl spacer. Biological screening revealed that some of the synthesized dimers are active against influenza A (H1N1) virus and coxsackievirus B3 with IC50 values of 13 and 4.5 μM, respectively. [ABSTRACT FROM AUTHOR]

2-Aminobenzimidazoles react with acetylene in the KOBut/DMSO superbase system (80°C, 20 min) to give benzimidazo[1,2-a]imidazoles and benzimidazo[1,2-a]pyrimidines formed by the self-assembly of the starting compounds with two or three molecules of acetylene. Vinyl derivatives of 1,3-dihydro-2H-benz[d]imidazole-2-imine were also isolated. [ABSTRACT FROM AUTHOR]