Hetero analogs of alloxazines. 2. Structure and tautomerism of 6,8-dimethyl-7,9-dioxo-5h-6,7,8,9-tetrahydropyrimido[4,5-b][4′,5′-e][1,4]thiazines

It is demonstrated by ¹³C NMR spectroscopy that the dipyrimidothiazines that are formed in the reaction of 1,3-dimethyl-5-nitro-6-chlorouracil with 4-R-5-amino-6-mercaptopyrimidines are dipyrimido[4,5-b][4,5-e] [1,4]thiazines. The tautomeric transformations of these compounds were studied.For communication 1, see [1]Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1426–1432, October, 1992.     

Bioluminescent detection of insect pheromones using an enzyme-based flow injection analysis system

The combination of flow injection analysis with chemiluminescent detection is shown to provide extremely selective and sensitive detection of insect pheromones which possess an aldehyde moiety. The flow injection analysis system provides reproducible control of both the reaction chemistry and the sample introduction process. Microliter volume samples can be precisely handled and analyzed with this experimental configuration. The detection system is based on the luciferase-catalyzed oxidation of reduced flavin mononucleotide which occurs in the presence of aldehydes with carbon backbones of between 14 and 16 carbons. A limit of detection of 3 fmol of tetradecyl aldehyde is demonstrated and the system is shown to be insensitive to the presence of various organic solvents up to concentrations of approximately 10%. The key experimental variables which control sensitive detection of pheromone at the femtomole level with be investigated and discussed.     

Sorption of Ion Associates on Polyurethane Foams and Its Application to Sorption–Spectroscopic and Test Methods of Analysis

The results of studying the sorption of various ion associates on polyurethane foams were generalized. The main sorption-affecting factors were found to be the nature, hydrophobicity, and charge of the associate ion; the nature and concentration of the counter ion; the composition of the polymer unit of the polyurethane foam; and the pH and salt composition of the aqueous phase. Correlation equations were proposed to relate the partition coefficients with the hydration energy of counter ions in the ion associates of cationic dyes and metal complexes of 1,10-phenanthroline and with the number of carbon atoms in the alkyl fragment of cationic alkyltrimethylammonium surfactants. A sorption scheme was proposed and substantiated. Examples were given of the practical use of sorption for determining anionic and cationic surfactants, phenols, 1-naphthol, Fe(III), and Ru(IV).     

4-Hydroxy-2-quinolones 131. Bromination of 3-allyl-4-hydroxy-2-oxo-1,2-dihydroquinoline

The bromination of 3-allyl-4-hydroxy-2-oxo-1,2-dihydroquinoline by molecular bromine is accompanied by the closure of a five membered furan ring and gives the corresponding 2-bromomethyl-3,9-dihydro-2H-furo[2,3-b]quinolin-4-one. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1677–1686, November, 2007.     

Condensation reaction with methylketones and aromatic compounds containing electron-repelling groups

Aryl tellurium trichlorides and tribromides undergo condensation reactions with acetone, acetophenone, N-dimethylaniline and resorcinol, giving rise to aryl tellurium dihalides. Aryl tellurium triiodides are not reactive. The dihalides derived from N-dimethylaniline and resorcinol undergo ionic interchange reactions with halide ions. When treated with reducing agents the dihalides derived from N-dimethylaniline are reduced to the corresponding tellurides, while the other dihalides are cleaved to the diaryl-ditellurides.     

Theoretical analysis of magnetic and electric hyperfine interactions on 1H and 2H nuclei of bis(acetylacetonato) copper (II)

The INDO method has been used in calculating the tensors of hyperfine structure and the electric field gradient on the ¹H and ²H nuclei in Cu(acac)₂. The procedure used in calculating the magnetic resonance parameters (MRPs) is based on an accounting for one-center and two-center Coulomb integrals of dipole-dipole interaction. The influence of out-of-plane step distortion of the complex on the MRPs is examined critically.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 24, No. 2, pp. 149–155, March–April, 1988.The authors wish to express their appreciation to P. V. Schastnev and S. A. Mustafaev for valuable discussion and for assistance in the work.