Poly(DMI-1, 2-Diazinediylethene-l, 2-Diols)

Oligomers of 2 to 9 units having a diazinediylethene-1, 2-diol repeating unit have been prepared by a cyanide ion-catalyzed self-condensation of pyridazine-3, 6-, pyrazine-2, 5-, or pyrimidine-4, 6-dialdehyde. These are the first known representatives of a class of conjugated polymeric enediol materials derivable specifically from these three structurally related diazine dialdehydes. The oligomers, isolated as their potassium salts, are soluble in acid and base with an isoelectric point at pH 6.5. In base, they give dark red-brown solutions whose color, attributable to their semidione ion radical form, is rapidly discharged by oxygen (air) or by the addition of ferric ion, which gives an immediate precipitation of the black chelate. Of several possible methods evaluated for the preparation of the free dialdehydes, only that involving ozonization of the distyryldiazines was found to be of preparative value.     

Polymerization of Bis(Pyridine)bis-(2,4,6-tribromophenoxo)copper(II) Complex (Py2Cu(TBrP)2) by Electrooxidation and Structural Characterization by 1H-NMR, 13C-NMR,and FTIR Spectroscopies

Abstract

Electroinitiated polymerization of bis(2,4,6-tribromophenoxo)- bis(pyridine)copper(II) complex was achieved in dimethylformamide-tetrabutylammonium tetrafluoroborate solvent-electrolyte couple under air or nitrogen at room temperature by constant potential electrolysis. Polymerization conditions were based on the peak potentials measured by cyclic voltammetry. The structural analyses of the polymers were done by ¹H-NMR, ¹³C-NMR, and FTIR spectral analyses along with molecular weight measurements by cryoscopy. The poly(dibromo phenylene oxide)s obtained only at oxidation potentials in either atmosphere were found to be highly linear, indicating mainly 1,4-catenation was taking place.     

On triazoles XIX: The reaction of 5-amino-1,2,4-triazoles with functionalized acetoacetic esters

Summary Different functionalized alkyl 3-oxo-butyrates (2) were reacted with 5-amino-3-Q-1H-1,2,4-triazoles (1) to yield3 and4 type 1,2,4-triazolo[1,5-a]pyrimidinones. In case of2 (R ¹=methyl,R ²=1-ethoxycarbonylethyl,R ³=ethyl) beside the corresponding derivative4 the unexpected 5,6-dihydro-6,8-dimethyl-7-ethoxycarbonyl-3-methylthio-1,2,4-triazolo[4,3-a]-1,3-diazepin-5(9H)-one (7) was isolated, representing a novel ring system.

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Über Triazole, 19. Mitt.: Die Reaktion von 5-Amino-1,2,4-triazolen mit funktionalisierten Acetoessigestern

Zusammenfassung Verschiedene funktionalisierte 3-Oxo-buttersäurealkylester (2) wurden mit 5-Amino-3-Q-1H-1,2,4-triazolen (1) umgesetzt, wobei 1,2,4-Triazolo[1,5-a]pyrimidinone der Typen3 und4 erhalten wurden. Im Fall von2 (R ¹=Methyl,R ²=1-Ethoxycarbonylethyl,R ³=Ethyl) wurde neben dem erwarteten Derivat4 das unerwartete 5,6-Dihydro-6,8-dimethyl-7-ethoxycarbonyl-3-me-thylthio-1,2,4-triazolo[4,3-a]-1,3-diazepin-5(9H)-on (7) isoliert, welches ein neues Ringsystem darstellt.

     

Synthesis of N-nitrooxazolidines and N-nitrotetrahydro-1,3-oxazines from N-(2-hydroxyalkyl)- and N-(3-hydroxyalkyl)sulfamates

A method was developed for the preparation of functionally substituted N-nitrooxazolidines and N-nitrotetrahydro-1,3-oxazines by nitration of the products obtained in the reactions of N-(2-hydroxyalkyl)- and N-(3-hydroxyalkyl)sulfamates with formaldehyde.     

The tert-butyl-NNO-azoxy group in the synthesis of 1,2,4-benzotriazin-3(4H)-one 1-oxides

Treatment of 2-(tert-butyl-NNO-azoxy)anilines with phosgene at 20 °C was proposed as a novel route to 1,2,4-benzotriazin-3(4H )-one 1-oxides. This method involves a new reaction, viz., an intramolecular interaction of the tert-butyl-NNO-azoxy group with a C-electrophile (leading to the formation of the N(2)—C(3) bond of the triazine ring) followed by elimination of the tert-butyl group. Complete assignment of the signals in the ¹H and ¹³C NMR spectra of the compounds obtained was performed. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1507–1509, August, 2007.     

Synthesis of 2-alkyl-1,2,4-benzotriazin-3(2h)-ones and 2-alkyl-1,4-dihydro-1,2,4-benzotriazin-3(2h)-ones

A preparative method for the synthesis of 2-alkyl-1,2,4-benzotriazin-3(2H)-ones 3 was developed. The method involves treatment with sodium cyanate of 2-alkylbenzotetrazinium tetrafluoroborates, which exist in solutions in equilibrium with o-(alkylazo)aryldiazonium tetrafluoroborates. Reduction of compounds 3 with zinc in acetic acid afforded 2-alkyl-1,4-dihydro-1,2,4-benzotriazin-3(2H)-ones. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 346–349, February, 2006.     

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.

     

3-(4-Phenyl-1,2,4-triazol-3-yl)chromones

The condensation of 4-phenyl-1,2,4-triazol-3-ylacetonitrile with 2-methyl-, 4-ethylresorcinol, and with pyrogallol gave α-(4-phenyl-1,2,4-triazol-3-yl)-2,4-dihydroxyacetophenones. Upon treatment with acid anhydrides and chlorides and subsequent hydrolysis these form 7-hydroxy-3-(4-phenyl)-1,2,4-triazol-3-yl)chromones with different substituents in both the benzene and the pyrone rings. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1676–1684, November, 2005.     

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.     

The formation of 1,2,4-triazolylimidazolidine-2,4-diones in reactions of 3-aryl-1,2,4-triazin-5(2H)-ones with alkylureas

Recyclization of the addition products of alkylureas to 3-aryl-1,2,4-triazin-5(2H)-ones affording 1,2,4-triazole derivatives was found to occur in Ac₂O.     

Stereochemicai study of 7-aryl-1,7,8,8a-tetrahydro-3(2H)indolizinones by1H and13C NMR

Stereochemistry of 7-aryl-1,7,8,8a-tetrahydro-3(2H)-indolizinones was studied by¹H and¹³C NMR. Complete assignment of¹H NMR signals and analysis of¹H-¹H coupling constants were performed using the iterative PANIC program. Values of³ J _6,7,³ J _7,8endo, and⁴ J _5,7 allow one to unambiguously identify the correspondingexo- andendo-stereoisomers. For stereoisomers with exo-orientation of H(7), complete assignment of¹³C NMR signals was performed on the basis of analysis of the¹³C-¹H coupling constants using two dimensional heteronuclear shift-correlating spectroscopy.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 591–593, March, 1996.     

Beiträge zur Stereochemie der Additionsreaktionen an 3,4,5,6-Tetrahydropyridin-1-oxide. 2. Mitt.

4-tert-Butyl-3,4,5,6-tetrahydropyridine-1-oxide (1) and 6-butyl-3,4,5,6-tetrahydropyridine-1-oxide (2) were prepared and isolated in their monomeric forms. In many aprotic solvents these compounds are converted into their dimers. The main product in both cases is the addition product of identical enantiomers. In the case of compound1 a very small amount of an addition product of the optical antipodes is also formed, which is the thermodynamically most stable isomer. In contrast, compound2 yielded an addition product of the optical antipodes in larger amounts, with a thermodynamically less favourable structure. These dimerizations are solvent dependent, reversible and sensitive to steric hindrance.

     

1-Methyl-2(3,4)-(1-vinylpyrrol-2-yl)pyridinium iodides: some structural features revealed by 1H and 13C NMR spectroscopy

The reactions of 2-, 3-, and 4-(1-vinylpyrrol-2-yl)pyridines with methyl iodide afford the corresponding quaternary salts. Analysis of their ¹H and ¹³C NMR spectra showed that the quaternization of the nitrogen atom considerably enhances the -acceptor effect of the pyridine ring on the pyrrole ring and on the vinyl group. 1-Methyl-2-(1-vinylpyrrol-2-yl)pyridinium iodide contains no weak intramolecular C--H...N hydrogen bond present in the starting compound.     

Volume phase transition and structure of poly(N-isopropylacrylamide) microgels studied with 1H-NMR spectroscopy in D2O

Thermoresponsive colloidal microgels were prepared by polymerisation of N-isopropylacrylamide (NIPAM) with varying concentration of a cross-linking monomer, N,N-methylenebisacrylamide (MBA), in water with either 0.4 or 6.7 mM concentration of an anionic surfactant, sodium dodecylsulphate (SDS). Volume phase transitions of the prepared microgels were studied in D₂O by ¹H-NMR spectroscopy including the measurements of spin–lattice (T1) and spin–spin (T2) relaxation times for the protons of poly(N-isopropylacrylamide) (PNIPAM) at temperature range 22–50 °C. In addition, microcalorimetry, turbidometry, dynamic light scattering and electrophoretic mobility measurements were used to characterise the aqueous microgels. The results from the different characterisation methods indicated that PNIPAM microgels prepared in 6.7 mM SDS concentration are structurally different compared to their correspondences prepared in 0.4 mM concentration. Increasing MBA concentration in the microgel synthesis appears to increase the structural heterogeneity in both cases of SDS concentration. PNIPAM structures with significantly higher molecular mobilities at temperatures above 35 °C were observed in the microgels prepared in 0.4 mM SDS concentration, as indicated by the ¹H NMR relaxation times of different PNIPAM protons. We conclude that the high mobilities measured with NMR at elevated temperatures and also the clearly negative values of zeta potential are in connection to a fairly mobile surface layer with polyelectrolyte nature and a consequent high local lower critical solution temperature.     

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.     

NMR spectroscopic study of the (Z)/(E)-isomerism of 1-aryl-3-arylamino-2-propen-1-ones in solution and in the crystalline state

Summary ¹H,¹³C, and CP/MAS¹³C NMR spectra of sixp-substituted 1-aryl-3-arylamino-2-propen-1-ones in solution and in the solid state are reported and discussed. In the proteon-accepting solvent dimethylsulfoxide, electronegative substituents shift the isomeric equilibrium to the (E)-isomer. Bulky substituents promote crystallization of the (Z)-form.

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NMR-Spektroskopische Untersuchung der (Z)/(E)-Isomerie von 1-Aryl-3-arylamino-2-propen-1-onen in Lösung und im Kristallzustand (Kurze Mitt.)

Zusammenfassung ¹H-,¹³C- und CP/MAS-¹³C-NMR Spektren von sechsp-substituierten 1-Aryl-3-arylamino-2-propen-1-onen in gelöstem und festem Zustand werden berichtet und diskutiert. In protonenakzeptierendem Dimethylsulfoxid verschieben elektronegative Substituenten das Gleichgewicht zum (E)-Isomer. Große Substituenten begünstigen die Kristallisation in der (Z)-Form.

     

Direction of isomerization of 5-hydroxy-3-propargylthio-1,2,4-triazines according to 1H/15N heteronuclear multiple bond correlation (HMBC) spectra

We have studied isomerization of 6-substituted 5-hydroxy-3-propargylthio-1,2,4-triazines using base catalysis. We have used NMR correlation spectroscopy (¹H/¹⁵N HMBC spectra) to prove the structure of the regioisomer formed. The type of regioisomer formed (3,6-dimethylthiazolo[3,2-b]-1,2,4-triazin-7-one) allows us to say that isomerization occurs as a direct propynyl rearrangement. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 453–457, March, 2006.     

The Reactions of 6-(tert-Butyl)-3-hydrazino-1,2,4-triazin-5(2H)-one with Carbonyl Compounds

The reaction of 6-(tert-butyl)-3-hydrazino-1,2,4-triazin-5(2H)-one with acetone and benzaldehyde yields the corresponding hydrazones. In the presence of thionyl chloride the benzaldehyde hydrazone is converted to 3-(tert-butyl)-6-phenyl-1,2,4-triazolo[4,3-b]-1,2,4-triazin-2(1H)-one and this can also be formed via the acylation of the starting hydrazinotriazinone using benzoyl chloride.     

A new synthesis for 1,2,4-triazolo[1,5-a]-pyridines and 1,2,4-triazolo[1,5-a]isoquinolines

Summary Condensation of cyano acid hydrazide1 with cyclopentanone in refluxing ethanolic piperidine yields hydrazone2. With mixtures of aliphatic aldehydes and different active methylene reagents,2 reacts to 1,2,4-triazolo[1,5-a]pyridines (8a–f). Compound2 also reacts with arylidenes9a–g to give triazolopyridines10a–g. Reaction of2 with aromatic aldehydes affords compounds13a–c. Diazotation of2 with aryldiazonium chloride in ethanol at 0 °C leads to the azo adducts15a–d. The thieno-1,2,4-triazolopyridine16 is obtained by reaction of8a with elementary sulfur.16 undergoes cycloaddition with -nitrostyrene, maleic anhydride, N-arylmalemide, and acrylonitrile yielding the isoquinolines21–24. All new compounds have been characterized by their IR,¹H NMR, and mass spectra.

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Ein neuer Syntheseweg für 1,2,4-Triazolo[1,5-a]pyridine und 1,2,4-Triazolo[1,5-a]isochinoline

Zusammenfassung Kondensation des Cyanohydrazids1 mit Cyclopentanon in ethanolischem Piperidin bei Rückflußtemperatur ergibt das Hydrazon2. Mit Gemischen aus aliphatischen Aldehyden und verschiedenen Verbindungen mit aktiven Methylengruppen reagiert2 zu 1,2,4-Triazolo[1,5-a]pyridinen (8a–f). Verbindung2 reagiert außerdem mit den Arylidenen9a–g zu den Triazolopyridinen10a–g. Umsetzung von2 mit aromatischen Aldehyden führt zu den Verbindungen13a–c. Diazotierung von2 mit Aryldiazoniumchloriden in Ethanol bei 0°C ergibt die Azoaddukte15a–d. Das Thieno-1,2,4-triazolylpyridin16 erhält man durch Reaktion von8a mit elementarem Schwefel.16 geht it -Nitrostyrol, Maleinsäureanhydrid, N-Arylmaleimid und Acrylnitril eine Cycloaddition zu den Isochinolinen21–24 ein. Alle neuen Verbindungen wurden durch ihre IR-,¹H-NMR- und Massenspektren charakterisiert.

     

Determination of the structure of 7-diethylamino-4-(1,2,3-triazol-1-yl)-2H-1-benzopyran-2-one derivatives using two-dimensional heteronuclear chemical-shift correlated NMR techniques

¹H and¹³C NMR spectra of 7-diethylamino-4-(1,2,3-triazol-1-yl)-2H-1-benzopyran-2-one derivatives have been studied. The location of the substituent in the 1,2,3-triazole ring was determined by the 2D COLOC method. It was established that the H(3) and H(5) protons in the coumarin moiety experience anisotropic influence of the phenyl subsituent at the C(5) atom in the triazole ring.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1330–1332, July, 1994.