Rearrangements of 4-(2-Aminophenyl)-1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylic acid diethyl ester

The treatment of 4-(2-aminophenyl)-1,4-dihydro-2,6-dimethyl-3,5-pyridinecarboxylic acid diethyl ester (III) with refluxing toluene or pyridine afforded 1,2,3,6-tetrahydro-2,4-dimethyl-2,6-methano-1,3-benzodiazocine-5,11-dicarboxylic acid diethyl ester (IV) as the major product. In addition, the following minor products were isolated: 2-methyl-3-quinolinecarboxylic acid ethyl ester (V), 3-(2-aminophenyl)-5-methyl-6-azabicyclo[3,3,1]-hept-1-ene-2,4-dicarboxylic acid diethyl ester (VI), and 5,6-dihydro-2,4-dimethyl-5-oxobenzo[c][2,7]naphthyridine-1-carboxylic acid ethyl ester (VII). In contrast, acidic conditions caused the conversion of III into V in a 95% yield. The formation of the latter appears to involve IV as an intermediate, since IV degraded rapidly in acid to give V in a quantitative yield.     

Syntheses and crystal structures of polymeric ionic triorganotin esters of 3,5-pyridinedicarboxylic acid and 5-nitroisophthalic acid

The triethylammonium dicarboxylatotriorganostannates, [(C₂H₅)₃NH][R₃Sn(3,5-pdc)]?·?mH₂O (3,5-pdc?=?3,5-pyridinedicarboxylate) (m?=?1, R?=?Me 1; m?=?0, R?=?Ph 2, PhCH₂ 3, n-Bu 4), [(C₂H₅)₃NH][R₃Sn(5-nip)] (5-nip?=?5-nitroisophthalate) (R?=?Me 5, Ph 6, PhCH₂ 7, n-Bu 8) have been prepared from triethylamine, 3,5-pyridinedicarboxylic acid, 5-nitroisophthalic acid and triorganotin chloride. Complexes 1–8 have been characterized by elemental, IR, ¹H, ¹³C and ¹¹⁹Sn NMR analyses. Complexes 1, 2, 5 and 6 are also determined by single crystal X-ray diffraction. For 1, 2, 5 and 6, each carboxylate moiety is involved in coordination to a tin center via only one O atom showing that the Sn atoms are five-coordinate and exist in trigonal bipyramidal geometries. Moreover, for 2, 5 and 6, the nitrogen atoms of ammonium are hydrogen bonded to the pendant carboxyl oxygen. In 1, adjacent polymeric chains and triethylammonium are linked by hydrogen bonds through the co-crystallized water molecule, thus a 2D network is formed.     

1,4-二氢-2,6-二甲基-4-(3-硝基苯基)-3,5-吡啶二羧酸二(2-甲氧基乙基)酯的合成

对1，4－二氢吡啶类钙拮抗剂西尼地平进行了结构修饰。以双乙烯酮和乙二醇单甲醚为原料，经酯化、缩合、氨化和Hantzsch环化等反应合成了1，4－二氢－2，6二甲基－4－（3－硝基苯基）－3，5－吡啶二羟酸二（2－甲氧基乙基）酯，总收率71％。目标产物结构经^1H NMR和MS确证。     

The reaction of ethyl 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate with fullerene C60

Heating (100 °C, toluene) or photolysis (Nd³⁺ : YAG laser, = 532 mil, benzonitrile) of a mixture of ethyl 2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxylate (Hantsch ester) (1) and fullerene C₆₀ under anaerobic conditions results in the formation of fullerene hydrogenation products and ethyl 2,6-dimethylpyridine-3,5-dicarboxylate, which is the product of dehydrogenation of1, identified by IR spectroscopy and mass spectrometry. The triplet state of C₆₀ is quenched by the Hantsch ester.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 10, pp. 2531–2534, October, 1996.     

The reaction of optically active α-aminocarboxylic acid hydrazides with triethyl orthoesters

New derivatives of 2-(1-amino-1-phenylmethyl)-1,3,4-oxadiazole and 1,2,4-triazin-6-one were synthesised in the reactions of optically active α-aminocarboxylic acid hydrazides and triethyl orthoesters in xylene. The electronic and steric effects of substituents at the α position influencing the formation of five- or six-membered products are discussed.     

Synthesis of novel copper compounds containing isonicotinic acid and/or 2,6-pyridinedicarboxylic acid: third-order nonlinear optical properties

Two novel compounds, [Cu₂(pydc)₂(inta)₂(H₂O)₂]·3H₂O 1 (pydc?=?2,6-pyridinedicarboxylic acid, inta?= isonicotinic acid) and [Cu(pydc)₂][Cu(H₂O)₅]·2H₂O 2, have been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction, elemental analyses and IR spectra. Compound 1 exhibits reverse saturable absorption and self-defocusing. X-ray structural analysis reveals that Compounds 1 and 2 both possess π–π stacking and hydrogen-bonding interactions forming three-dimensional (3D) networks. Crystal data for 1: a?=?7.2345(14), b?=?12.219(2), c?=?17.069(3)?Å, α?=?90.44(3), β?=?91.82(3), γ?=?93.56(3)°, Z?=?1, R1?=?0.0435, wR2?=?0.1216. Crystal data for 2: a?=?8.3708(17), b?=?27.386(6), c?=?9.6170(19)?Å, α?=?90.00, β?=?98.14(3), γ?=?90.00°, Z?=?3, R1?=?0.0742, wR2?=?0.2160.     

Reactions of derivatives of phosphorylacetic acid hydrazides with 3,5-di-tert-butyl-4-hydroxybenzyl acetate

Abstract

To obtain new polyfunctional inhibitors of radical-chain oxidative processes, C- and N-benzylation of a number of phosphorylacetic acid hydrazide derivatives is realized in their reactions with 3,5-di-tert-butyl-4-hydroxybenzyl acetate. N-benzylation of mixtures of Z and E isomers of hydrazones of phosphorylacetic acid derivatives proceeds stereoselectively with the formation of only E_C=N isomers.     

4-hydroxy-2-quinolones. 41. Reaction of hydrazides of 1-R-2-oxo-4-hydroxyquinoline-3-carboxylic acids with ethyl orthoformate

The boiling of hydrazides of 1-R-2-oxo-4-hydroxyquinoline-3-carboxylic acids in an excess of ethyl orthoformate leads to the formation of ethyl esters of the corresponding quinoline-3-carboxylic acids, the structure of which was confirmed by X-ray diffraction analysis.For the Communication 40, see [1].National Pharmaceutical Academy of Ukraine, Kharkov 310002. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 207–211, February, 2000.     

Determination of glyphosate and aminomethylphosphonic acid by capillary electrophoresis with indirect detection using pyridine-2,6-dicarboxylic acid or 3,5-dinitrobenzoic acid

Glyphosate (GlyP), a widely used nonselective herbicide, and aminomethylphosphonic acid (AMPA), GlyP’s most common product of degradation in the environment, seem not to pose any major health threats. However, due to their persistence and the large quantities applied worldwide, they have become a source of concern. This justifies that their simple and swift determination is of considerable relevance. This work presents two indirect capillary electrophoretic methodologies using as chromophores 3,5-dinitrobenzoic acid (DNB) and pyridine-2,6-dicarboxylic acid (PDC), both associated with hexadecyltrimethylammonium bromide (CTAB). Although both methods showed suitable analytical parameters, DNB evidenced to be slightly superior. The recoveries values were close to 100%, correlation coefficients were above 0.99 and the limits of detection (LODs) values were below 0.5 mg L^?1 (2.9 µmol L^?1) and 0.4 mg L^?1 (3.6 µmol L^?1) for GlyP and AMPA, respectively.     

稀土-2,6-吡啶二甲酸-氧化三苯基膦配合物的合成及其荧光性质

稀土离子尤其是Sm,Eu,Tb,Dy因为其良好的荧光性能而得到了广泛的研究和应用[1,2]。吡啶二甲酸和氧化三苯基膦这两种配体有较大范围的共轭π键,在近紫外区又都有较宽的吸收带和较强的吸收峰,与稀土离子配位后可以构成有效的能量传递体系,将它们在近紫外区吸收的能量有效地传递给     

Synthesis and Crystal Structure of 3,5-Dicyano-2,6-diethylthiopyridine

3,5-Dicyano-2,6-diethylthiopyridine has been synthesized by the alkylation of cyanothioacetamide with ethyl iodide in DMF and its molecular and crystal structures have been investigated. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1351–1354, September, 2005.     

Addition-elimination in the reaction of alpha-hydroxyalkyl radicals with 3,5-pyridinedicarboxylic acid and nicotinic acid: example of inner sphere organic electron transfer

Reactions of alpha-hydroxyalkyl radicals with 3,5-pyridinedicarboxylic acid (3,5-PDCA) and nicotinic acid (NA) were studied at appropriate pHs in aqueous solutions by pulse radiolysis technique. At pH 1, CH(3)C*HOH and *CH(2)OH radicals were found to react with 3,5-PDCA by rate constants of 2.2 x 10(9) and 5.1 x 10(8) dm(3) mol(-1) s(-1), respectively, giving radical adduct species. The adduct species formed in the reaction of CH(3)C*HOH radicals with 3,5-PDCA underwent unimolecular decay (k = 9.8 x 10(4) s(-1)) giving pyridinyl radicals. Reaction of (CH(3))(2)C*OH, CH(3)C*HOH, and *CH(2)OH radicals with NA at pH 3.3 gave the adduct species which subsequently decayed to the pyridinyl radicals. At pH 1, wherein NA is present in the protonated form, (CH(3))(2)C*OH radicals directly transfer electrons to NA, whereas CH(3)C*HOH and *CH(2)OH radicals react with higher rate constants compared with those at pH 3.3, initially giving the adduct species which subsequently undergo elimination reaction giving pyridinyl radicals. Reactions of alpha-hydroxyalkyl radicals with 3,5-pyridinedicarboxylic acid and nicotinic acid are found to proceed by an addition-elimination pathway that provides one of the few examples of organic inner sphere electron-transfer reactions. Rate constant for the addition reaction as well as rate of elimination varies with the reduction potential of alpha-hydroxyalkyl radicals.     

The quasi-symmetric OHN and ODN bridges in the adducts of 3,5-dimethylpyridine with 3,5-dinitrobenzoic acid

The crystal structure of the adduct of 3,5-dimethylpyridine and 3,5-dinitrobenzoic acid (DMP-DNB) has been determined at room temperature and 80 K for both undeuterated and deuterated compounds. The monoclinic crystals are isomorphous, space group P2₁/c and Z = 4. Very strong OHN hydrogen bonds are almost linear with fully disordered (1:1) bridge hydrogen atoms between oxygen and nitrogen atoms. This is well reflected in the difference in electron density maps the contours of which depend both on cooling and deuteration. The intramolecular hydrogen bond lengths are 2.550(2) Å for the (OHN) and 2.563(2) Å for (ODN) at room temperature and 2.529(2) Å for (OHN) and 2.531(2) Å for (ODN) at 80 K. Therefore, there is a small but meaningful isotope effect upon the O…N hydrogen bridge length at room temperature and no Ubbelohde isotope effect is observed at 80 K. The infra-red spectra show very broad stretching protonic bands in the 200–1600 cm⁻¹ range. The isotopic ratio v(H)/v(D) at room temperature is about 1.1.     

Complexes of Eu(III), Tb(III) and Cu(II) with proton transfer compound between 2,6-pyridinedicarboxylic acid and 2-aminobenzothiazole: characterization of the structures and physical properties

A proton transfer compound, (ABTH)⁺(PydcH)^? (1), obtained from 2-aminobenzothiazole (ABT) and 2,6-pyridinedicarboxylic acid (Pydc) as well as its Eu(III), Tb(III), and Cu(II) complexes (ABT)₃[Eu(Pydc)₃]·5H₂O (2), (ABT)₃[Tb(Pydc)₃]·5H₂O (3), and (ABT)[Cu(Pydc)(PydcH)]·3H₂O (4) were obtained under ambient conditions and structurally verified by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, powder X-ray diffraction (PXRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA), and magnetic measurements. Compounds 2–4 are the first known solids containing complex anions with Pydc ligands, 2-aminobenzothiazole cations (ABT), and solvate water molecules. During the synthesis of 3, a secondary phase with the formula ABTCl?H₂O was obtained and characterized by elemental analysis and single-crystal X-ray diffraction. The asymmetric unit of 5 consists of six symmetry independent ABT cations, six chlorides, and six water molecules. The two lanthanide complexes showed characteristic emissions of Eu³⁺ and Tb³⁺ ions. The good solubilities of these complexes in water and their luminescence properties make them attractive luminescent labels of biological molecules.     

The synthesis and structure of a novel 1D copper(II) weak coordination polymer with 2,6-pyridinedicarboxylic acid

A novel copper complex, [Cu(dipic)(H₂O)₂] _n (H₂dipic?=?2,6-pyridinedicarboxylic acid), was synthesized and its crystal structure determined by X-ray diffraction. The complex has a polymeric structure of infinite one-dimensional (1D) zigzag chains, consisting of six-coordinate Cu(II) units. Each copper(II) ion is in a distorted octahedral environment with a CuNO₅ core: two oxygen atoms and one nitrogen atom from one dipic anion, one oxygen atom from an adjacent dipic ligand and two oxygen atoms from coordinated water. Each dipic anion connects two copper ions via a μ₂-oxygen atom. The zigzag 1D-chains are linked by extensive hydrogen bonds to form 2D infinite sheets.     

Study of the reaction of 3,5-diamino-4-carbomethoxypyrazole with acetoacetic ester. Synthesis of pyrazolo[1,5-a]pyrimidine

X-Ray structural analysis has shown that condensation of 3,5-diamino-4-carbomethoxypyrazole with acetoacetic ester occurs to give derivatives of 7-oxopyrazolo[1,5-a]pyrimidine (rather than 5-oxo as proposed previously).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 78–81, January, 2000.     

Fabrication of poly(2,6-pyridinedicarboxylic acid)/MWNTs modified electrode for simultaneous determination of guanine and adenine in DNA

The fabrication of poly(2,6-pyridinedicarboxylic acid)/MWNTs modified glass electrode(PPDA/MWNTs/GCE) was proposed and used for individual or simultaneous determination of guanine and adenine.The performances of the PPDA/MWNTs/GCE were characterized with cyclic voltammetry(CV).The modified electrode exhibited enhanced electrocatalytic behavior and good stability for the detection of guanine and adenine.Differential pulse voltammetry(DPV) was used to determine the concentration of guanine,adenine.The detection limit(S/N = 3) for guanine and adenine was 0.045μmol/L and 0.05μmol/L,respectively.The electrochemical method for the measurement of guanine and adenine in calf thymus DNA was also developed with this modified electrode and the result was satisfactory.     

Study on the Retention Behavior of Aromatic Carboxylic and Sulfonic acid on a New Anion Exchange Column

Ion chromatography (IC) has gradually developed into a preferred method for the determination of inorganic anions. And in recent years some low molecular aliphatic acid can be also separated in the ion exchange column with the development of stationary phase. But for the determination of aromatic ionic compounds there are some problems. The aromatic anions show enhanced retention due to interaction with the π electrons of the aromatic backbone. Although the addition of an organic modifier can alleviate the difficulty, it is not the ultimate solution. IonPac AS20 column was developed using a unique polymer bonding technology and its substrate coating is aliphatic backbone. The polymer is completely free of any π electron‐containing substituents in the AS20 column. In this paper, the retention behavior of aromatic carboxylic and sulfonic acid on two hydroxide‐selective columns, IonPac AS11‐HC, AS16, and the new column AS20 was also studied. The result showed that the retentions of ten compounds on three columns were different with each other because of their different column characteristics. Among them 4‐chlorobenzene sulfonic acid, 3,5‐dihydric benzoic acid and salicylic acid obviously exhibited the weakest retention on the IonPac AS20. It was showed that π‐π bond function between anion and stationary phases was weakened in AS20 column because its polymer was completely free of any π electron‐containing substituents. So in this paper the AS20 was selected as an analytical column to separate ten aromatic ionic compounds, fumaric acid with conjugate bond included. The retention behavior, separation of the ten compounds and effect of temperature on their retention in the anion‐exchange column AS20 (2 mm) were studied. The result showed that those compounds could be separated with each other when running in gradient program and the organic modifier was unnecessary during the separation. So it is showed that AS20 column can be used as a separating column because its polymer is completely free of any π electron‐containing substituents. Finally, the effect of temperature on the retention behavior in AS20 column was studied and it was showed that the retention of nine compounds exhibited endothermic behavior.     

Novel chromium and molybdenum complexes of a dimerized isonicotinic acid hydrazide

Sunlight irradiation of [M(CO)₆], M?=?Cr and Mo with isonicotinic acid hydrazide (inh) was investigated. The photochemical process resulted in dimerization of inh with elimination of a hydrazine molecule to give N′-isonicotinoylisonicotino hydrazide (ininh). Two complexes with molecular formulas [MO₂(ininh)] were isolated and characterized by elemental analysis, infrared, mass and ¹H NMR spectroscopy. The UV-vis spectra of the complexes in DMSO showed visible bands due to ligand-to-metal charge transfer. Thermal properties of the complexes were investigated by TG thermogravimetry.