The composition of transformation products of 2,4,6-trinitrobenzoic acid in the aqueous-phase hydrogenation over Pd/C catalysts

Due to a detailed analysis of NMR spectra of the reaction solutions with different composition obtained by the aqueous-phase catalytic (Pd/C) hydrogenation of 2,4,6-trinitrobenzoic acid, the intermediate compounds were identified and a more substantiated mechanism was proposed for the formation of the main reaction products—1,3,5-triaminobenzene and cyclohexane-1,3,5-trione trioxime. The condensation of the 1,3,5-triaminobenzene molecules produced by a complete hydrogenation of 2,4,6-trinitrobenzoic acid was shown to result in the formation of a paramagnetic heterocyclic compound.     

Synthesis of 3,5-disubstituted 1-amino-1,3,5-triazine-2,4,6-triones (or 1-aminocyanurates) by cyclic transformation of 1,3,4-oxadiazol-2(3H)-one derivatives

The 5-aryl(or methyl)-3-phenylcarbamoyl-1,3,4-oxadiazol-2(3H)-ones 2 , in the presence of sodium hydride in anhydrous dimethylformamide, were transformed into 1-benzamido(or acetamido)-3,5-diphenyl-1,3,5-triazine-2,4,6-trione derivatives 7 in poor yields. However, compounds 7 were obtained in better yields when the sodium salts of 5-aryl(or methyl)-1,3,4-oxadiazol-2(3H)-ones 1 were treated with two equivalents of aryl(or ethyl)isocyanates. Acidic hydrolysis of 1-acetamido-3,5-diphenyl-1,3,5-triazine-2,4,6-trione ( 7i ) provided the corresponding free N-amino derivative 9 . Nitrous deamination of 9 gave the known 3,5-diphenyl-1,3,5-triazine-2,4,6-trione ( 11 ). This cyclic transformation is the first one to be reported providing 1,3,5-triazine-2,4,6-trione derivatives.     

Solvent induced quadrupole polarization of the molecules of diazo and diazocarbonyl compounds: Quantum-chemical investigation

Equilibrium structural parameters, atomic charges, and quadrupole moments of the molecules of 2,4,6-tris(diazo)cyclohexane-1,3,5-trione, 3,6-bis(diazo)cyclohexane-1,2,4,5-tetraone and its anion, isomeric 3,6-bis(diazonium)cyclohexanediondioles and 4,4′-bis(diazonium)-1,1′-biphenyl in a vacuum and in dichloromethane were calculated by the quantum chemical method PBE0/cc-pVTZ using the polarizable continuum model (PCM).The p-quinoid dication is more favorable than o-quinoid dication by 20 kcal mol-1 in a vacuum and by 13 kcal mol⁻¹ in dichloromethane.The norm of the quadrupole moment of the centrosymmetric molecules in a polarizable medium increases while that of the dications decreases. The quadrupole polarization of molecules and molecular ions by the solvent does not change their symmetry point group.     

Synthesis and characterization of 1,3,5-tris((1/2<Emphasis Type="Italic">H</Emphasis>-tetrazol-5-yl)methyl)-1,3,5-triazinane-2,4,6-trione

2,2′,2″-(2,4,6-Trioxo-1,3,5-triazinane-1,3,5-triyl) triacetonitrile (or tris-(cyanomethyl)-isocyanurate) and 1,3,5-tris((1/2H-tetrazol-5-yl)methyl)-1,3,5-triazinane-2,4,6-trione (or tris-(5-tetrazolylmethyl)-isocyanurate) were synthesized with new methods. High yields, simple methodology, and cheapness are advantages of the methods. Furthermore, 1,3,5-tris((1/2H-tetrazol-5-yl)methyl)-1,3,5-triazinane-2,4,6-trione was synthesized in the less hazardous condition. The compounds were characterized by elemental analysis, IR, ¹HNMR, ¹³CNMR and mass spectroscopic analysis. In addition, DSC/TGA measurements were carried out to determine the thermal behavior of the final product.     

Participation of compact planar 1,3,5-tri(buta-2,3-dien-1-yl)-1,3,5-triazinane-2,4,6-trione in Pd(0) catalysed seven component cascade reactions delivers novel tunable molecular architecture

We report the spatially controlled, protecting group free, catalytic assembly of a library of nineteen 7-component cascade products generated from a novel planar trisallenyl 1,3,5-triazinane-2,4,6-trione core in combination with aryl iodides and amines with excellent regio and good stereoaselectivity for Z,Z,Z-isomers.     

Proton-acceptor properties of azahomofullerene and fullerenoaziridine containing a cyanuric acid fragment

¹³C and ¹H NMR and UV spectral studies on 1,3-diallyl-5-[4-(azahomo[60]fullereno)butyl]hexahydro-1,3,5-triazine-2,4,6-trione ([5,6]-open isomer) and 1,3-diallyl-5-[4-(aziridino[60]fullereno)butyl]hexahydro-1,3,5-triazine-2,4,6-trione ([6,6]-closed isomer), as well as quantum-chemical calculations, showed that only the latter possesses weakly basic properties.     

2,4,6-三对氨基苯氧基-1,3,5-均三嗪的合成

以三聚氯氰和对硝基苯酚为原料,经取代、还原合成了2,4,6-三对氨基苯氧基-1,3,5-均三嗪。对Pd/C水合肼、SnCl2·2H2O-HCl及Pd/C催化加氢三种不同还原体系进行比较。采用1H-NMR、FT-IR和元素分析方法对产物进行结构表征。     

Design and synthesis of novel spirocyclopropyl cyclohexane-1,3-diones and -1,3,5-triones for their incorporation into potent HPPD inhibitors

We report the design and the efficient synthesis of novel spirocyclopropyl cyclohexane-1,3-dione and -1,3,5-trione units to be incorporated into potent HPPD inhibitors. New routes involving original combinations of synthetic equivalents of α-cyclopropyl ketone-α-anion and α-cyclopropyl ester-β-cation are described.     

Cyclotrimerization of aryl isocyanates catalyzed by alkoxyallenes through zwitterionic mechanism

Alkoxyallenes ( 1 ) are found to catalyze cyclotrimerization of aryl isocyanates ( 2 ) in dimethylformamide (DMF) to afford 1,3,5-triaryl-s-triazine-2,4,6-trione ( 3 : cyclic trimer of 2 ), although the reaction of 1 with 2 in bulk gave the corresponding copolymer. In order to speculate about the mechanism of the cyclotrimerization, macrozwitterion 4 , was prepared by copolymerization of 1 and 2 in bulk, and the catalytic activity of 4 was further studied. Cyclotrimerization of 2 was promoted by 4 and quenching of 4 with methanol completely destroyed the catalytic activity. Consequently, the alkoxyallene-catalyzed cyclotrimerization of 2 is assumed to take place through a zwitterion generated from 1 and 2 .     

Synthesis of 1,1,1,7,7,7-hexafluoroheptane-2,4,6-trione, the simplest fluorinated 1,3,5-triketone

A simple, convenient and effective method to synthesize 1,1,1,7,7,7-hexafluoroheptane-2,4,6-trione, the simplest fluorinated 1,3,5-triketone, on a preparative scale was developed. The title compound was obtained by a Claisen-type double condensation of acetone with trifluoroacetic acid ethyl ester and isolated as a solid monohydrate from the reaction mixture. Subsequent dehydration proceeds smoothly to produce the desired compound as an individual substance. Its peculiar tautomeric (keto-enol, ring-chain) features in various solvents are discussed.     

Synthesis of 8,10-dimethyl-1,10b-dihydro[1,3,5]triazino-[2,1-a]isoindole-2,4,6(3H)-trione by Direct arylation of 1,3,5-triazine-2,4(1H,3H)-dione

Direct arylation of 1,3,5-triazine-2,4(1H,3H)-dione with mesitylene afforded a novel fused heterocyclic system, 8,10-dimethyl-1,10b-dihydro[1,3,5]triazino[2,1-a]isoindole-2,4,6(3H)-trione.     

Effect of the reduction conditions of the supported palladium precursor on the activity of Pd/C catalysts in hydrogenation of sodium 2,4,6-trinitrobenzoate

The study addresses the effect of the reduction conditions of palladium polynuclear hydroxo complexes (PHC) supported on the Sibunit carbon material on the dispersion of the metal particles and the activity of 0.5%Pd/Sibunit catalysts in the selective hydrogenation of sodium 2,4,6-trinitrobenzoate to 1,3,5-triaminobenzene in an aqueous solution (temperature of 323 or 343 K, pressure of 0.5 MPa). The palladium PHC were reduced using the most common methods pertaining to catalyst preparation: liquid-phase reduction with sodium formate and reduction in a hydrogen flow at elevated temperature. It was found that high-temperature reduction in the gas phase gives rise to Pd particles with a markedly lower dispersion compared with the sample obtained under mild liquid-phase reduction conditions. The catalytic activity of the sample containing large Pd particles proved to be higher than the activity of the catalyst obtained by reduction with sodium formate.     

新型树状化合物1,3,5-三{3-[2,4,8,10-四氧杂\|9(3,5-二(2,6-二氧杂-4,4-二羟甲基环己基)苯基]螺[5.5]十一烷基}苯的制备

本实验采用季戊四醇与苯三甲醛缩合, 制成树状化合物1,3,5-三{3-|[2,4,8,10-四氧杂-9(3,5-二(2,6-二氧杂-4,4-二羟甲基环己基)苯基)螺[5.5]十一烷基}苯. 该类树状分子具有手性螺环结构, 手性密度很高, 可开发成理想的高效手性催化剂[3~8], 具有诱人的应用前景.     

Trimerization products of trifluoroacetone: critical solvent effect on position and kinetics of anomeric equilibria

In the presence of bases, trifluoroacetone is known to trimerize leading to configurationally labile 6-methyl-2,4,6-tris(trifluoromethyl)tetrahydro-2H-pyran-2,4-diols 1a,b and 2a,b, structurally close to fluorinated carbohydrates. We report herein a complete study of their behavior in solution. The remarkable solvent effect on the two equilibria (1a <--> 1b; 2a <--> 2b) was rationalized using solvent basicity measures and polarity scales. Solvents of weak donor number were found to favor the diastereoisomers 1a and 2a, which were subsequently isolated. According to their X-ray analyses, they both possess a concave structure with 1,3-cis-diaxial hydroxyl groups. A complementary kinetic study illustrated that acidic conditions can drastically reduce the equilibration rate, allowing the use of a wide range of solvents. Finally, a reexamination of previously published trimerization conditions using sodium or magnesium amalgam revealed that, contrary to the suggestion by two independent reports, 1,3,5-tris(trifluoromethyl)cyclohexane-1,3,5-triol 3/4 was neither formed as the principal product in place of 1a,b and 2a,b nor could it be detected as a minor product.     

The thermodynamic properties of the esters of 2,4,6-trinitrobenzoic acid

The thermodynamic properties of the esters of 2,4,6-trinitrobenzoic acid have been investigated using the techniques of hot-stage microscopy and differential scanning calorimetry. In each case an enantiotropic transition process was observed below the melting point. This transition has been explained in terms of restricted rotation and conformational freedon of the flexible alkyl chain in the crystalline solid state.     

Microwave Assisted Synthesis of Triaryl Cyanurates

Rapid synthesis of triarylcyanurates (2,4,6-triaryloxy-1,3,5-triazine) was carried out by reacting cyanuric chloride with the sodium salt of hydroxyaryl compounds in water using focused microwaves. Environmentally friendly procedure and isolation of pure products in excellent yields are important features of this method.     

GC/MS and ESI/MS identification of the new generation plasticizers - cis and trans isomers of some 1,2-cyclohexane dicarboxylic acid di(n- and isononyl) esters

1,2-Cyclohexane dicarboxylic acid diisononyl ester is also known as diisononyl cyclohexane-1,2-dicarboxylate (DINCH) is a complex mixture of the hydrogenation products of diisononyl benzene-1,2-dicarboxylate (DINP). They are the new generation plasticizers used instead of the dialkyl benzene-1,2-dicarboxylate in order to improve the flexibility of polymers (mainly PVC) and strongly reduce the toxic effects on human health during their release from polymers to the environment. The identification of these compounds was done by syntheses of some DINCH constituents, i.e. cis and trans isomers of three di(n- and isononyl) cyclohexane-1,2-dicarboxylates, such as di(3,5,5-trimethylhexyl) cyclohexane-1,2-dicarboxylates, di(2-methyloctyl) cyclohexane-1,2-dicarboxylates and dinonyl cyclohexane-1,2-dicarboxylates by catalytic hydrogenation of appropriate DINP and their analyses by gas chromatography – mass spectrometry (GC/MS) and electrospray - mass spectrometry (ESI/MS) methods. Both GC data (values of the retention times t_R and arithmetic retention indices I_A) and mass spectra obtained for these isomers allowed to determine their chemical structures. ESI/MS mode of analysis of these compounds gives the knowledge about their mass fragmentation without the differentiation between individual cis and trans isomers.     

Synthesis of 1,6-dihydro-1,6-dihydroxybenzo[1,2-d:3,4-d′]bistriazole, 4- and 5-nitro-1,6-dihydro-1,6-dihydroxybenzo[1,2-d:3,4-d′]bistriazole and 4,7-dihydro-1,4,7-trihydroxy-1H-benzo-[1,2-d:3,4-d′:5,6-d″]tris[1,2,3]triazole

1,6-Dihydro-1,6-dihydroxybenzo[1,2-d:3,4-d′]bistriazole and 4- and 5-nitro-1,6-dihydro-1,6-dihydroxybenzo[1,2-d:3,4-d′]bistriazole were synthesized starting from 2,4-dinitrosore-sorcinol, whereas 4,7-dihydro-1,4,7-trihydroxy-1H-benzo[1,2-d:3,4-d′:5,6-d″]tris[1,2,3]-triazole was synthesized starting from phloroglucinol. The reaction of trinitrosophloroglucinol with hydrazine hydrate in acetic acid led to 2,4,6-tridiazocyclohexane-1,3,5-trione.     

2，4，6-三〔芳基氨基)-1，3，5-三嗪衍生物的合成方法和微波效应研究

用碳酸氢钠作扑酸剂，将芳香胺和氰尿酰氯在1，4-二氧六环中回流状态下反 应合成了7个2，4，6-三(芳基氨基)-1，3，5-三嗪衍生物，其中6个是新化合物． 与已有文献报道的方法相比，条件温和，易于操作，收率高．所合成化合物的结构 通过元素分析，FAB-MS，IR确定．在二氧六环：DMF为10：3(V：V)的混合溶剂中， 研究了在微波照射下和常规加热下反应速率的差异．结果表明，微波加热比常规加 热下的反应速率至少高10倍以上．     

Thioether functional chain extender for thermoplastic polyurethanes

In this study, a novel three functional chain extender(TATATRIOL) was synthesized from the reaction of 1,3,5-tri(prop-2-en-1-yl)-1,3,5-triazinane-2,4,6-trione(TATA) with 2-sulfanylethanol. Then new thermoplastic polyurethanes(TPUs) were synthesized by a one-step bulk polymerization from the reaction of 1,1'-methanediylbis(4-isocyanatocyclohexane)(H12MDI), a poly(ethylene adipate) based polyester polyol and a chain extender. Butane-1,4-diol(BD) and the newly synthesized monomer, TATATRIOL, were used as chain extenders. The effects of TATATRIOL on the properties of the TPU were investigated and compared to those of the TPU prepared with BD. The TPUs which derived from the sulfur containing chain extender displayed lower modulus and high elongation at break values than the analogous TPUs derived from BD. Moreover sulfur containing TPUs exhibited higher thermal stability.