Acylative kinetic resolution of racemic amines using N-phthaloyl-(S)-amino acyl chlorides

A comparative study of the kinetic resolution of racemic 2-methyl-1,2,3,4-tetrahydroquinoline and 2,3-dihydro-3-methyl-4H-1,4-benzoxazine using N-phthaloyl-(S)-amino acyl chlorides as chiral acylating agents is described. Temperature and solvent effects on the stereochemical features have been examined. It has been found that N-phthaloyl-(S)-phenylalanyl and N-phthaloyl-(S)-2-phenylglycyl chlorides bearing aromatic substituents close to the stereogenic centre are more stereoselective acylating agents than N-phthaloyl-(S)-alanyl chloride. For the preparative kinetic resolution of racemic amines N-phthaloyl-(S)-phenylalanyl chloride proved to be the most appropriate chiral acylating agent.     

New 5-arylamino-4-(5-nitrofuran-2-yl)pyrimidines as promising antibacterial agents

A facile synthetic approach to 5-arylamino-4-(5-nitrofuran- 2-yl)pyrimidines by the Buchwald–Hartwig cross-coupling with various anilines has been developed. All synthesized compounds demonstrated a significant level of in vitro antibacterial activity against Neisseria gonorrhoeae, Streptococcus pyogene and Staphylococcus aureus, including their drug-resistant strains, which is much higher than that of the commercial drug Spectinomycin.     

Determination of enantiomeric purity of 1-substituted 3-amino-1,2-dicarba-<Emphasis Type="Italic">closo</Emphasis>-dodecaboranes by HPLC on chiral stationary phases

A determination of enantiomeric purity of 1-substituted (Me, Ph, and Prⁱ) 3-amino-1,2dicarba-closo-dodecaboranes by HPLC on chiral Chiralcel OD-H and Chiralpac AD stationary phases involving preliminary phthaloylation of 3-aminocarboranes has been suggested as a general method.     

Cyclization of N-alkylazinium cations with bifunctional nucleophiles. 24. Synthesis of condensed 1,2,4-triazino- and 1,2,4-oxadiazino[5,6-b]quinoxaline systems

Cyclization of quinoxalinium salts with amidoximes and amidhydrazones yields partially hydrogenated derivatives of new 1,2,4-oxadiazino- and 1,2,4-triazino[5,6-b]quinoxaline heterocyclic systems.For Communication 23, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1118–1121, August, 1987.     

Bis(acetylaryl) podands in the synthesis of fluorine-containing bis(β-diketones) joined by a polyether spacer

O-Alkylation of 2-acetylphenols with α,ω-dichloro derivatives of oligoethylene glycols in the presence of KOH and Al₂O₃ in DMF gave the corresponding podands. Their condensation with ethyl trifluoroacetate afforded fluorine-containing bis(β-diketones) with the aryl fragments linked by conformationally flexible polyether spacers.     

Synthesis,structures, and magnetic properties of crystals of dinuclear copper(II) and cobalt(II) complexes with 3-(3,5-dimethylpyrazol-1-yl)-6-R-1,2,4,5-tetrazines

Dinuclear complexes of Cu^II with 3-(3,5-dimethylpyrazol-1-yl)-6-(2-hydroxyethylami-no)-1,2,4,5-tetrazine (1) and CoII with 3-(3,5-dimethylpyrazol-1-yl)-6-(piperidin-1-yl)-1,2,4,5- tetrazine (2) were synthesized and structurally characterized, and the magnetic (SQUID) and resonance (EPR) properties of van der Waals crystals based on these complexes were studied. Unusual behavior of the effective magnetic moment μ_eff(T) is observed at T < 60 K. A nonmonotonic increase in μeff(?) for 1 (s~6 %) and a 20% reduction of μeff(?) for 2 have a common origin and are due to the influence of spin-orbital coupling on the character of the splitting between the t2g and eg levels of the central ion. Distortions of the coordination site “switch on” a positive (1) or negative (2) contribution of the orbital magnetic moment near 6 K. Irreversible temperature behavior of μeff(T) in the heating and cooling regimes in the vicinity of 60 K suggests that the character of structural distortions and the magnetic properties are related to ligand geometry. This factor plays a significant role in crystal engineering of magnetoactive structures with polynitrogen ligands.     

Synthesis and structure of fluoroalkyl containing lithium 1,3-diketonates

Russian Journal of General Chemistry - Methods of synthesis and IR, mass, NMR 1H, 19F, 13C spectra as well as X-ray analysis of fluoroalkyl containing lithium 1,3-diketonates are reviewed.