Novel Synthesis,Characterization of N1,N1,N4,N4-tetrakis (2-hydroxyethyl) terephthalamide (THETA) and Terephthalic Acid (TPA) by Depolymerization of PET Bottle Waste Using Diethanolamine

Chemical depolymerization of poly(ethylene terephthalate) (PET) waste is a possible remedy to huge amount of solid waste generation as it results in degradation products that possess a potential of recyclability. PET bottle waste was depolymerized by aminolysis using diethanolamine. Novel synthesis of N¹, N¹,N⁴,N⁴-tetrakis (2-hydroxyethyl) terephthalamide (THETA) with 73-76% yield and terephthalic acid (TPA) with 78-82% yield was achieved. The purified products were analyzed by FTIR, melting point, DSC, DTG and ¹H-NMR. THETA has various applications in the synthesis of rigid polyurethane foam, unsaturated polyester resins and also as a cross linking agent/ hardener for epoxy resins.     

A mass spectrometric method to determine activities of enzymes involved in polyamine catabolism

An analytical method for the determination of three polyamines (putrescine, spermidine, and spermine) and five acetylpolyamines [N¹-acetylspermidine (N¹AcSpd), N⁸-acetylspermidine (N⁸AcSpd), N¹-acetylspermine, N¹,N⁸-diacetylspermidine, and N¹,N¹²-diacetylspermine] involved in the polyamine catabolic pathway has been developed using a hybrid tandem mass spectrometer. Heptafluorobutyryl (HFB) derivatives of these compounds and respective internal standards labeled with stable isotopes were analyzed simultaneously by TOF MS, based on peak areas appearing at appropriate m/z values. The isomers, N¹AcSpd and N⁸AcSpd were determined from their fragment ions, the acetylamidopropyl and acetylamidobutyl groups, respectively, using MS/MS with ¹³C₂-N¹AcSpd and ¹³C₂-N⁸AcSpd which have the ¹³C₂-acetyl group as an internal standard. The TOF MS method was successfully applied to measure the activity of enzymes involved in polyamine catabolic pathways, namely N¹-acetylpolyamine oxidase (APAO), spermine oxidase (SMO), and spermidine/spermine N¹-acetyltransferase (SSAT). The following natural substrates and products labeled with stable isotopes considering the application to biological samples were identified; for APAO, [4,9,12-¹⁵N₃]-N¹-acetylspermine and [1,4,8-¹⁵N₃]spermidine (¹⁵N₃-Spd), respectively; for SMO, [1,4,8,12-¹⁵N₄]spermine and ¹⁵N₃-Spd, respectively; and for SSAT, ¹⁵N₃-Spd and [1,4,8-¹⁵N₃]-N¹-acetylspermidine, respectively.     

Tetraalkylammonium Ions in Aqueous and Non-aqueous Solutions

Property data for tetraalkylammonium cations, [H(CH₂) _n ]₄N⁺, are reviewed. They pertain to the isolated cations and their transfer from the gas phase into aqueous solutions. Various properties of these cations in aqueous and non-aqueous solutions and data for their transfer between these are also reviewed. Emphasis is placed on the dependence of data on the length n of the alkyl chains rather than on the absolute values. Most of the data are available only for the first four members of the series. The properties of the isolated ions increase linearly with the chain length. Molar enthalpies of formation of the gaseous and aqueous cations, and absolute standard molar enthalpies of hydration, are derived. Standard molar entropies of dissolution of several salts in water are obtained from their solubilities and enthalpies of solution. The molar entropies of the crystalline iodides of the first four members of the series then give the standard partial molar entropies of the aqueous cations and their molar entropies of hydration. The standard partial molar volumes in aqueous and non-aqueous solutions are quite linear with n and in non-aqueous solutions the molar volume hardly depends on the nature of the solvent. On transfer from water to non-aqueous solvents the volume of Me₄N⁺ suffers some shrinkage, that of Et₄N⁺ appears to be unaffected, but from Pr₄N⁺ onwards an increasing expansion takes place. This unexpected result is tentatively explained by hydrophobic intra-molecular association of pairs of alkyl chains in aqueous solutions, resulting in a tightening of the structure. The transfer of the R₄N⁺ cations from water into non-aqueous solvents is governed by a large positive entropy change, outweighing the smaller positive enthalpy change. The transport properties of the aqueous R₄N⁺ cations are non-linear with n. A major impediment to movement is thus the sticking of the water molecules to the ice-like hydrophobic hydration sheaths of the larger cations. The number of water molecules affected by the hydrophobic cations is open to widely differing estimates resulting from various approaches, and constitute an open issue.     

Features of the reaction of unsymmetrical 2-mercapto-imidazoles with aromatic and aliphatic ketones

The cyclization of unsymmetrical 2-mercaptoimidazoles with aliphatic and aromatic ketones has been studied. Using ¹H NMR and X-ray analysis it has been shown that 4-R¹-1H-2-mercaptoimidazoles undergo selective oxidative cyclization to the corresponding 3-R³-2-R²-6-R¹-imidazo[2,1-b][1,3]thiazoles while 6-R⁴-1H-2-mercaptobenzo[d]imidazoles give a mixture of 6-R⁴-3-R²-2-R³-benzo[4,5]imidazo[2,1-b][1,3]thiazole and 7-R⁴-3-R²-2-R₃-benzo[4,5]imidazo[2,1-b][1,3]thiazole in the ratio 1: 1. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 115–122, January, 2007.     

Preparation of 2-125I-Testosterone and Its Use as Ligand for Radioimmunoassay in Serum

Abstract

A radioiodination technique is described which consists of heating Testosterone (T) with Na¹²⁵I and hydrogen peroxide in acetic acid in sealed vial. The binding capacity of labelled substances was measured after thin layer chromatography of the reaction mixture. One compound was selected for radioimmunoassay on the basis of its binding capacity for anti-T serum. Standard curves utilizing tritiated and radioiodinated T, under identical conditions, were superimposible. Serum hormone concentrations determined by the two tracers were comparable. Accuracy, precision and sensitivity were satisfactory. Mass spectroscopy and nuclear magnetic resonance of the unlabelled iodinated T indicated that iodine is in C-2.     

A Unique,Porous C3N4 Nanotube for Electrochemiluminescence with High Emission Intensity and Long-Term Stability: The Role of Calcination Atmosphere

Developing excellent strategies to optimize the electrochemiluminescence (ECL) performance of C₃N₄ materials remains a challenge due to the electrode passivation, causing weak and unstable light emission. A strategy of controlling the calcination atmosphere was proposed to improve the ECL performance of C₃N₄ nanotubes. Interestingly, we found that calcination atmosphere played a key role in specific surface area, pore-size and crystallinity of C₃N₄ nanotubes. The C₃N₄ nanotubes prepared in the Air atmosphere (C₃N₄ NT-Air) possess a larger specific surface area, smaller pore-size and better crystallinity, which is crucial to improve ECL properties. Therefore, more C₃N₄^•− excitons could be produced on C₃N₄ NT-Air, reacting with the SO₄^•− during the electrochemical reaction, which can greatly increase the ECL signal. Furthermore, when C₃N₄ nanotube/K₂S₂O₈ system is proposed as a sensing platform, it offers a high sensitivity, and good selectivity for the detection of Cu²⁺, with a wide linear range of 0.25 nM~1000 nM and a low detection limit of 0.08 nM.     

Umsetzung von 1,5-Dimethyl-2,3,3,4-tetrachlor-1,5,2,4-diazadiphosphorinan-6-on mit Anilinderivaten,Heptamethyldisilazan und tert.-Butylamin: Oxidative Addition von Tetrachlor-o-benzochinon an einige P(III)-haltige Produkte

The reaction of the title compound 1 with the p-R-aniline derivatives (R═H, F, OCH₃, NO₂, and NH₂) led to the formation of the aza-2σ³,4σ³-diphosphetidines 2a– 2e, whereas 2-trimethylsiloxyaniline furnished the azadiphosphetidine 2f. The reaction of the sterically crowded 2,6-dimethylaniline with 1 furnished the disubstituted derivative 3. The tricyclic compound 5 was formed during the reaction of 1,2-phenylenediamine with 1. Heptamethyldisilazane formed the aza-2σ ³ ,4σ ³ -diphosphetidine 6 on reaction with 1. The bulkier tert.-butylamine formed with 1 a mixture of the aza-2,4-diphosphetidine 7a and the disubstituted derivative 7b, which could not be separated. The reaction of 2b and 6 with tetrachloro-o-benzoquinone resulted in the formation of the bis-spirophosphoranes 8 and 9b, respectively. The formation of the monospirophosphorane 9a was observed in the ³¹P NMR spectrum. The characterization of compounds is based in particular on NMR investigations (¹H, ¹³C, ³¹P). 2a was characterized by a single-crystal X-ray structure analysis. The dimethylurea fragment is planar; the four-membered ring is folded about the P···P vector by 38.7°.     

CO LMR spectrum of14N16O and its analysis with spectra of14N17O and14N18O

LMR spectra for v=1←0 transitions of¹⁴N¹⁶O in X²II_{1/2, 3/2} states were observed at 5.6 μm and 5.4 μm of CO laser. Introducing the advanced isotopic molecular constant scaling function to Hund’s case (a) diatomic structure model, these spectra were analyzed and fitted together with all reliable previous spectral data of¹⁴N¹⁶O as well as¹⁴N¹⁷O and¹⁴N¹⁸O. A full set of precise molecular parameters and their vibrational dependencies have been determined with much higher precision (1–2 orders for most parameters). Many of them have been obtained for the first time. Using isotopic scaling function, the molecular constants of¹⁴N¹⁷O and¹⁴N¹⁸O were deduced.     

Extraction and Spectrophotometric Determination of Manganese(VII) with N1-Hydroxy-N1,N2-Diphenylbenzamidine

Abstract

Spectrophotometric determination of manganese(VII) at 614 nm after its extraction with N¹ -hydroxy-N¹,N²-diphenylbenzamidine into amyl alcohol at pH 7–8 is described. Beer's law was obeyed for 0.1–10 μg ml^?1 Mn(VII). The effects of experimental variables and of several diverse ions on the determination of manganese(VII) have been studied. The method has been applied to the determination of manganese in steels and in water extracts of a commercial tea and is found to be simple, precise and highly selective.     

Spectral and electrochemical studies of ruthenium(II) complexes with N-methyl-4-nitrobenzaldehyde and N-methyl-4-nitrobenzophenone thiosemicarbazone: Potential anti-trypanosomal agents

N⁴-Methyl-4-nitrobenzaldehyde thiosemicarbazone (H4NO₂Fo4M), N⁴-methyl-4-nitrobenzophenone thiosemicarbazone (H4NO₂Bz4M) and their ruthenium(II) complexes [Ru(4NO₂Fo4M)₂(PPh₃)₂] (1), [Ru(4NO₂Bz4M)₂(PPh₃)₂] (2), [Ru(4NO₂Fo4M)₂(dppb)] (3) and [Ru(4NO₂Bz4M)₂(dppb)] (4) (dppb = 1,4-bis(diphenylphospine)butane) were obtained and characterized. The crystal structure of H4NO₂Fo4M has been determined. Electrochemical studies have shown that the nitro anion radical, one of the proposed intermediates in the mechanism of action of nitro-containing anti-trypanosomal drugs, is formed at approximately −1.00 V in the free thiosemicarbazones as well as in their corresponding ruthenium(II) complexes, suggesting their potential to act as antitrypanosomal drugs. The natural fluorescence of H4NO₂Fo4M, H4NO₂Bz4M and complexes (1)–(4) provides a way to identify and to monitor their concentration in biological systems.     

Synthesis of partially saturated N-substituted 4H-3,1-benzothiazine-2(1H)-thiones

Summary Acid-catalyzed reaction of 2-arylidenecyclohexanones1 with N-substituted dithiocarbamic acids2 gave open-chain addition products3 and4. Dehydration of3 and4 afforded only one of the three possible isomeric N-substituted 4H-3,1-benzothiazine-2(1H)-thiones5 and6.

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Synthese von partiell gesättigten N-substituierten 4H-3,1-Benzothiazin-2-(1H)-thionen

Zusammenfassung Die säurekatalysierte Reaktion von 2-Arylidencyclohexanonen1 mit N-substituierten Dithiocarbaminsäure2 ergab die offenkettigen Additionsprodukte3 und4. Die Dehydratation von3 und4 führte ausschließlich zu einem der drei möglichen N-substituierten 4H-3,1-Benzothiazin-2(1H)-thion-Isomeren5 und6.

     

Ketendithioacetal-S-imide

Starting from 2-isopropylidene-1,3-dithiane, various ketene-dithioacetal-S-imides have been prepared and characterized by¹H- and¹³C-NMR spectra.

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Ketendithioacetal-S-imideKurze Mitteilung

     

Methylation reaction for four DNA base molecules by methanediazonium ions

The methylation reactions at ten nucleophilic sites in four DNA base molecules with methanediazonium ions (CH₃N₂ ⁺) have been theoretically investigated including solvent effects at the B3LYP/6-31G^** and MP2/6-31G^** levels. The results show that all the methylation reactions have relatively small activation energy (<33.5 kJ/mol), and the methylation process is exothermic reaction and easy to occur. This study shows that the ultimate carcinogen CH₃N₂ ⁺ by NDMA can easily methylate DNA base molecules and form carcinogenic products. Supported by the Shanghai Municipal Education Commission (Grant No. YYY-07015) and Shanghai Institute of Technology (Grant No. YJ2007-36)     

CMPO/[Cnmim][NTf2]体系对Eu3+和UO22+的萃取行为

讨论了辛基(苯基)-N,N-二异丁基胺甲酰基甲基氧化膦(CMPO)/1-烷基-3-甲基咪唑双(三氟甲烷磺酰)亚胺盐([C_nmim][NTf₂],n=2,8,12)萃取体系分别对硝酸溶液中的铕离子(Eu³⁺)和铀酰根离子(UO₂²⁺)的萃取行为。主要研究了硝酸浓度、接触时间、温度、CMPO浓度对CMPO/[C_nmim][NTf₂]体系萃取性能的影响,并选取CMPO/[C2mim][NTf₂]体系对模拟高放废液中的镧锕元素进行了萃取分离。结果表明:随着离子液体侧链长度增长,萃取平衡时间逐渐延长;CMPO/[C2mim][NTf₂]体系对Eu³⁺的萃取是放热反应,萃取率随酸度增加而逐渐降低,对UO₂²⁺则是吸热反应,萃取率随酸度增加而逐渐升高;通过机理研究,推测出对Eu³⁺的萃取反应是离子交换,而对UO₂²⁺的萃取反应则是中性配位;CMPO/[C2mim][NTf₂]体系能有效的萃取模拟高放废液中的镧系、锕系元素,且在高酸下有一定的镧锕分离效果。     

Synthesis and structural characterization of a new polymeric zinc(II) complex with thiophene-2-carboxylic acid

A new polymeric zinc(II) complex with thiophene-2-carboxylic acid (α-tpc) of composition [Zn₂(C₂₀H₁₂O₈S₄)] _n was obtained and structurally characterized by X-ray diffraction, thermal analysis, nuclear magnetic resonance (NMR), and infrared spectroscopies. Upfield shift in the ¹H-NMR spectrum is explained by the crystalline structure, which shows the thiophene rings overlapping each other in parallel pairs. The compound crystallizes in the monoclinic system, space group P2₁/c, with a = 9.7074(4) Å, b = 13.5227(3) Å, c = 18.9735(7) Å, β = 95.797(10)°, and Z = 4. Three α-tpc groups bridge between two Zn(II) ions through oxygens and the fourth one bridges between one of these ions and the third one, symmetry related by a twofold screw axis. This arrangement gives rise to infinite chains along the crystallographic a direction. The metal atoms display an approximate tetrahedral configuration. The complex is insoluble in water, ethanol, and acetone, but soluble in dimethyl sulfoxide.     

Trimethylsilyl derivatives of N-Boc-cytosine and their effect on I2-mediated nucleosidation of O-MTM ethers

Mono- and bis(trimethylsilyl) derivatives of N⁴-Boc-cytosine were synthesized and characterized by ¹H NMR. Only the mono(trimethylsilyl)-N⁴-Boc-cytosine participates in the iodine-mediated nucleosidation of N-Fmoc-O-methylthiomethyl serine benzyl ester to produce the cytosine nucleoamino acid, while the bis(trimethylsilyl) derivative failed to give any product. A tentative mechanistic explanation is proposed.     

Zur Synthese und Struktur von 8-Nitro-imidazo [1,2-a]pyridinen

Summary The title compounds were synthesized by reaction of nitroketene aminals with -chlorovinylcarbonyl compounds. The chloromethylene malononitriles1 react with nitromethylenimidazolin (2 a) and -benzimidazoles2 b to yield the 8-nitro-2,3-dihydroimidazo[1,2-a]pyridines3 and the 4-nitropyrido[1,2-a]-benzimidazoles6, both containing an amino group. Analogously, from the special 3-chloro-2-propeniminium salt7 and2 a the imidazopyridine derivative9 was formed. The 3-aryl-3-chloro-2-propeniminium salts10 were converted into the nitro-dihydroimidazo[1,2-a]pyridines11 and the pyrido[1,2-a]benzimidazole12 containing the aryl group by reaction with2 a and2 b, respectively. The structures were investigated by 2-dimensional¹H/¹³C-NMR-spectroscopy.

     

Extraction and spectrophotometric determination of titanium(IV) withN 1-hydroxy-N 1,N 2-diphenylbenzamidine and thiocyanate

A precise, reliable, sensitive, and selective method for the determination of titanium(IV) is described. Titanium(IV) reacts withN ¹-hydroxy-N ¹,N ²-diphenylbenzamidine (HDPBA) and thiocyanate to form an orange-coloured mixed-ligand complex of stoichiometry 112 (Ti SCN^– HDPBA). The complex is quantitatively extractable into toluene from 0.05–0.15M hydrochloric acid. The spectrum of the complex exhibits an absorption maximum at 400 nm with a molar absorptivity of 20000M ^–1 cm^–1 and the coloured system obeys Beer's law in the concentration range 0.20–3.0 gml^–1 titanium. The effects of foreign ions and of various experimental parameters have been studied to establish the optimum conditions for the extraction and determination of titanium. The precision of the method has been evaluated and the relative standard deviation has been found to be 0.53%. The method has been successfully applied to the determination of titanium in synthetic matrices corresponding to titanium-containing ores, minerals, and alloys.