Chemistry of 2,4,6-trinitrobenzonitrile. 1. Nitro group substitution in 2,4,6-trinitrobenzonitrile under the action of anionic nucleophiles. Factors favoring substitution of the ortho-nitro group

The direction of the nitro group substitution (the ratio of the ortho/para substitution) in 2,4,6-trinitrobenzonitrile under the action of anionic nucleophiles (MeO^–, RS^–, and N₃ ^–) as well as of HCl was studied. The factors favoring ortho substitution were revealed.     

The Mannich reaction in the synthesis of N,S-containing heterocycles 6. New approaches to the synthesis of pyrimido[4,3-b][1,3,5]thiadiazine derivatives

Aminomethylation of 2,6-diamino-4-aryl-4H-thiopyran-3,5-dicarbonitriles in the Mannich reaction with p-toluidine and formaldehyde unexpectedly gave pyrimido[4,3-b][1,3,5]thiadiazine derivatives. The same compounds were obtained in an independent way involving a multicomponent cascade condensation of aromatic aldehydes, cyanothioacetamide, p-toluidine, and formaldehyde. For Part 5, see Izv. Akad. Nauk, Ser. Khim., 2007, 1384 [Russ. Chem. Bull., Int. Ed., 2007, 56, 1437]. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1420–1422, July, 2007.     

Novel generation of selenoaldehydes through stannic chloride-induced unsymmetrical C-Se bond cleavage of bis(N,N-dimethylcarbamoylseleno)methanes

Treatment of a benzene or a CH₂Cl₂ solution of bis(N,N-dimethylcarbamoylseleno)methanes with SnCl₄ afforded β-1,3,5-triselenanes, and the key intermediates, acylselonium ions and selenoaldehydes, were successfully trapped by using allyltrimethylsilane or 2,3-dimethyl-1,3-butadiene to obtain the allylation products or the cycloadducts, respectively.     

N-[Chloro(dimethylamino)methylene]-N-methylmethanaminium chloride (TMUCl Cl), the reagent of choice for the solid-phase synthesis of anilides

An effective solid-phase preparation of anilides from supported carboxylic acids is described by their activation as the corresponding acid chlorides with TMUCl Cl.     

N,N′-Dichloro bis(2,4,6-trichlorophenyl)urea (CC-2): an efficient reagent for the synthesis of α-chloro-nitroso compounds

A simple, efficient, rapid, and mild method for the synthesis of α-chloro-nitroso compounds is described using bis(2,4,6-trichlorophenyl)urea (CC-2).     

1,3-Di（2-p-tolylvinyl）-2,4,6-trinitrobenzene： X-ray Crystallo- graphic Analysis,Thermal Decomposition and DFT Calculations

In this paper, the synthesis, crystal culturing and single-crystal X-ray crystallography of 1,3-di（2-p-tolylvingl）-2,4,6-trinitrobenzene （DTTB） were reported. FT-IR, ^1H NMR and mass spectroscopy techniques were employed to characterize this compound. The results show that this single crystal belongs to triclinic system with space group P-1. Density functional theory （DFT） B3LYP was employed to optimize structure and calculate frequencies of the title compound. The calculated geometrical parameters were close to the corresponding experiment ones. The thermal decomposition of DTTB was investigated by DSC and TG-DTG methods at the heating rate of 10 ℃/min. It was observed that the initial decomposing temperature of DTTB was higher than that of TNTM, although its melting point was lower than that of TNTM, indicating that DTTB has higher heat resistant ability.     

Purge-and-trap preconcentration system coupled to capillary gas chromatography with atomic emission detection for 2,4,6-trichloroanisole determination in cork stoppers and wines

A method based on solvent extraction and purge-and-trap capillary gas chromatography with atomic emission detection (PT-GC-AED) for the determination of 2,4,6-trichloroanisole (TCA) in wines and cork stoppers was optimized and evaluated. TCA was previously extracted from the samples in pentane and the preconcentrated extract was reconstituted in water before being injected into the chromatograph by means of the PT system. Element-specific detection and quantification was carried out by monitoring the chlorine (479 nm) emission line. Two different calibration graphs were used to quantify TCA in the cork or the wine samples, owing to the interference produced by the ethanol content in the wines. Detection limits of 25 pg g(-1) and 5 ng l(-1) were obtained for corks and wines, respectively. The method provided recoveries from spiked samples ranging from 88.5 to 102.3%, confirming the reliability of the procedure and its suitability for routine monitoring.     

Thiomethylation of aromatic amines: efficient method for the synthesis of heterocyclic compounds

Primary aromatic amines were thiomethylated by formaldehyde and hydrogen sulfide. N-Substituted 1,3-thiazetidines, 4,5-dihydro-1,3,5-dithiazines, 3,4,5,6-tetrahydro-2H-1,3,5-thiadiazines, and 4,5-dihydro-1,3,5-oxathiazines were prepared for the first time starting from meta- and para-toluidines, meta-, para-, and ortho-anisidines, and para-xylidine. Amines characterized by higher mobility of hydrogen atoms produced previously unknown four-membered thiazetidines, whereas amines characterized by lower mobility of hydrogen atoms gave six-membered thiadiazines. The sorption properties with respect to silver were studied for the compounds, which were prepared from p-toluidine and p-anisidine.     

Zur selektiven Bestimmung von Tetrahydro-1,3,5-thiadiazin-2-thionen

Zusammenfassung Die Bildungskinetik gefärbter Chelate Me(R³-NH-CS₂)₂ mit Me=Cu oder Ni gestattet eine einfache Bestimmung des synthetischen Senfölbildners D47. Mit Kupferseifen lassen sich bis zu 10^–7 Mol D47 in gewissen CHCl₃-haltigen Medien bei 420 bzw. 440 nm über die Beziehung /trE/t=K · c ₀ schnell bestimmen. Spuren an Verunreinigungen sind dabei auszuschließen. In Zweifelsfällen ist eine Standardzusatz-Variante mit einem relativen Fehler von 2–3% anzuwenden. Die allmähliche Bildung eines stabilen Chelates mit NiCl₂ · 6 H₂O erwies sich als beste Methode zur spezifischen Bestimmung von D47 und dessen Homologen in Gegenwart der Zerfallsprodukte. Bei 440 nm stören lediglich Mineralsäuren sowie größere Mengen an Basen, organischen Säuren und aprotisch-dipolaren Lösungsmitteln. Das Beersche Gesetz wird im untersuchten Bereich von 10–1000 g D47/ml gut erfüllt. Medieneinflüsse und kinetische Besonderheiten werden kurz diskutiert.

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Selective determination of tetrahydro-1,3,5-thiadiazine-2-thionesPhotometry of the 3,5-dibenzylderivative D47 (Dibenzthione) as Cu-or Ni-benzyldithiocarbamidate

Kinetics of forming the coloured chelates Me(R³-NH-CS₂)₂) with Me = Cu or Ni permit a simple determination of the synthetic mustard oil former D47. Using copper soaps, only 10^–7 mol of D47 can rapidly be determined in certain CHCl₃-containing media at 420 or 440 nm, resp., by aid of the expression E/gDt=K · c ₀. Trace impurities must be absent. A standard addition variant with a relative error of 2–3 % may be applied to doubtful cases. The gradual formation of a stable chelate with NiCl₂ · 6 H₂O was found to be the best method for a specific determination of D47 and its homologues in presence of their degradation products. At 440 nm, only mineral acids or larger amounts of bases, organic acids, and aprotic dipolar solvents interfere. Beer's law is well obeyed in the studied range of 10–1000 g of D47/ml. The influences of media and kinetic peculiarities are discussed briefly.

     

Isomerism in metal complexes of 1,3,5-diazaphosphorinanes. Synthesis,crystal and molecular structure of conformers ofcis-bis(1,3,5-triphenyl-1,3,5-triazaphosphorinane)dichloroplatinum(II)

The crystal and molecular structures were determined for two individual conformers ofcis-bis(1,3,5-triphenyl-1,3,5-diazaphosphorinane)dichloroplatinum(II) differing in the rotation of the heterocyclic ligand planes around the P-Pt bond and in the orientation of the substituents at the phosphorus atoms in the ligands.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1650–1655, September, 1993.