Reaction of S-allyl and propargyl derivatives of 2-thiouracils with hydrobromic acid

Hydrobromic acid reacts with 2-methallylthio- and 2-prenylthio-4(3Н)-pyrimidinones with participation of the double bond to give the products of heterocyclization, and with 2-allylthio- and 2-propargylthio-6-methyl-4(3Н)-pyrimidinones, with the retention of the double bond and the formation of hydrobromides.     

Heterospin complexes based on dinuclear CuII triketonate and nitroxides

Heterospin complexes of bis(μ₂-1,1,2,2,8,8,9,9-octafluorononane-3,5,7-trionato)dicopper(II) ([Cu₂L₂]) with nitronyl nitroxides 2-(1-methyl-1H-pyrazol-4-yl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazole-1-oxyl 3-oxide (2) and 4,4,5,5-tetramethyl-2-(3-pyridinyl)-4,5-dihydro-1H-imidazole-1-oxyl 3-oxide (1) were synthesized and structurally characterized. Crystals of the complexes are formed by the discrete bis[1-methyl-4-(4,4,5,5-tetramethyl-3-oxide-1-oxyl-4,5-dihydro-1H-imidazol-2-yl)-1H-pyrazole]-bis (μ₂-1,1,2,2,8,8,9,9-octafluorononane-3,5,7-trionato)dicopper(II) etherate (3) and bis[3-(4,4,5,5-tetramethyl-3-oxide-1-oxyl-4,5-dihydro-1H-imidazol-2-yl)pyridine]-bis (μ₂-1,1,2,2,8,8,9,9-octafluorononane-3,5,7-trionato)dicopper(II) (4) molecules. Each Cu atom of the dinuclear chelate fragment coordinates one paramagnetic ligand through the N atom of the pyrazole or pyridine fragment, respectively. In complex 3, the paramagnetic ligands are located on one side of the plane of the chelate fragment, whereas the ligands in complex 4 are located above and below the plane of the chelate fragment. The magnetic properties of complexes 3 and 4 are determined by dominant antiferromagnetic exchange interactions between the unpaired electrons of the Cu^II atoms in the dinuclear Cu₂L₂ moiety. Dedicated to Academician O. M. Nefedov on the occasion of his 75th birthday. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1836–1840, November, 2006.     

Reaction of polyhaloalkyl-substituted chromones, pyrones, and furanones with salicylaldehydes as a direct route to fused 2H-chromenes

Polyhaloalkyl-substituted chromones, gamma-pyrones, and beta-furanones react with salicylaldehydes in the presence of piperidine to give a wide variety of fused 2H-chromenes in good yields. This novel annulation reaction presumably proceeds by a tandem intermolecular oxa-Michael addition and subsequent intramolecular Mannich condensation.     

Catalytic effect of nanosized metal oxides on the knoevenagel reaction

The effect of nanosized metal oxides (Al, Mg, Cu, Ni oxides) on the synthesis of chalcones that are key intermediate in the synthesis of Nitrendipine and Felodipine drugs was examined.     

Synthesis of 2-(polyfluoromethyl)pyrimido-[1,2-a]benzimidazole-4-carbaldehyde derivatives

1. Download : Download high-res image (109KB)
2. Download : Download full-size image

     

Fluorine-containing Heterocycles: X. Acetoacetamides in the Synthesis of Fluorine-containing Chromone

Fluorine-containing chromone-3-carboxamides were synthesized by reaction of tetra(penta)fluoro-benzoyl chlorides with acetoacetamides in dichloromethane in the presence of triethylamine. Nucleophilic substitution of fluorine atoms by amine rests in compounds synthesized was investigated.     

Synthesis and photophysical studies of novel 4-aryl substituted 2-phenyl-, 2-(fluoren-2-yl)- and 2-cymantrenylquinazolines

1. Download high-res image (129KB)
2. Download full-size image

     

4-Hydroxyproline containing podands as new chiralcatalysts for the asymmetric Biginelli reaction

The novel C₂-symmetric chiral organocatalysts of (2S,4R)-hydroxyproline containing podand type have been synthesized and evaluated in the asymmetric Biginelli reaction. Combination of polyether spacer with (2S,4R)-hydroxyproline allowed one to enhance the effect of the latter on enantioselectivity of the Biginelli reaction by a factor of 5. The best results have been achieved for salts of (2S,4R)-hydroxyproline containing podands with trifluoroacetic acid.

1. Download high-res image (100KB)
2. Download full-size image

     

Reaction of fullerene C60 with 2-azido-4,6-diphenylpyrimidine

The first representative of the pyrimidine-substituted [60]fullereno[1,2-b]aziridines was synthesized by the reaction of fullerene C₆₀ with 2-azido-4,6-diphenylpyrimidine. 2-(Azahomo[60]fullereno)-4,6-diphenylpyrimidine was found to be formed as a by-product. The electrochemical properties of the adducts were studied.     

Fluorocontaining Heterocycles: IX. Derivatives of Imidazo[2,1-b][1,3]benzothiazine

The heating of derivatives of benzimidazole-2-thione and imidazolidine-2-thione with tetra(penta)fluorobenzoyl chlorides in toluene or pyridine gave rise to fluorocontaining derivatives of imidazo[2,1-b][1,3]benzothiazine. The latter were studied in reactions of nucleophilic substitution of fluorine for amino groups.