Articles de revues : « Carboxy Pyridine »

1

Smith, Graham, Urs D. Wermuth et Jonathan M. White. « Zero-, one- and two-dimensional hydrogen-bonded structures in the 1:1 proton-transfer compounds of 4,5-dichlorophthalic acid with the monocyclic heteroaromatic Lewis bases 2-aminopyrimidine, nicotinamide and isonicotinamide ». Acta Crystallographica Section C Crystal Structure Communications 65, n^o 3 (21 février 2009) : o103—o107. http://dx.doi.org/10.1107/s0108270109004405.

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The structures of the anhydrous 1:1 proton-transfer compounds of 4,5-dichlorophthalic acid (DCPA) with the monocyclic heteroaromatic Lewis bases 2-aminopyrimidine, 3-(aminocarbonyl)pyridine (nicotinamide) and 4-(aminocarbonyl)pyridine (isonicotinamide), namely 2-aminopyrimidinium 2-carboxy-4,5-dichlorobenzoate, C4H6N3+·C8H3Cl2O4−, (I), 3-(aminocarbonyl)pyridinium 2-carboxy-4,5-dichlorobenzoate, C6H7N2O+·C8H3Cl2O4−, (II), and the unusual salt adduct 4-(aminocarbonyl)pyridinium 2-carboxy-4,5-dichlorobenzoate–methyl 2-carboxy-4,5-dichlorobenzoate (1/1), C6H7N2O+·C8H3Cl2O4−·C9H6Cl2O4, (III), have been determined at 130 K. Compound (I) forms discrete centrosymmetric hydrogen-bonded cyclic bis(cation–anion) units having bothR22(8) andR12(4) N—H...O interactions. In (II), the primary N—H...O-linked cation–anion units are extended into a two-dimensional sheet structureviaamide–carboxyl and amide–carbonyl N—H...O interactions. The structure of (III) reveals the presence of an unusual and unexpected self-synthesized methyl monoester of the acid as an adduct molecule, giving one-dimensional hydrogen-bonded chains. In all three structures, the hydrogen phthalate anions are essentially planar with short intramolecular carboxyl–carboxylate O—H...O hydrogen bonds [O...O = 2.393 (8)–2.410 (2) Å]. This work provides examples of low-dimensional 1:1 hydrogen-bonded DCPA structure types, and includes the first example of a discrete cyclic `heterotetramer.' This low dimensionality in the structures of the 1:1 aromatic Lewis base salts of the parent acid is generally associated with the planar DCPA anion species.

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2

Guo, Lei, Jia-Qun Li, Yu-Ting Xie, Chu-Qin Lu et Jian-Zhong Wu. « A one-dimensional lead(II) coordination polymer with terminal and bridging 5-carboxy-2-(pyridin-3-yl)-1H-imidazole-4-carboxylate ligands ». Acta Crystallographica Section C Structural Chemistry 70, n^o 5 (8 avril 2014) : 428–31. http://dx.doi.org/10.1107/s2053229614006883.

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In the coordination polymer catena-poly[[[diaqua[5-carboxy-2-(pyridin-3-yl)-1H-imidazole-4-carboxylato-κ2 N 3,O 4]lead(II)]-μ-5-carboxy-2-(pyridin-3-yl)-1H-imidazole-4-carboxylato-κ3 N 3,O 4:N 2] dihydrate], {[Pb(C10H6N3O4)(H2O)2]·2H2O} n , the two 5-carboxy-2-(pyridin-3-yl)-1H-imidazole-4-carboxylate ligands have different coordination modes, one being terminal and the other bridging. The bridging ligand links PbII cations into one-dimensional coordination polymer chains. The structure is also stabilized by intra- and interchain π–π stacking interactions between the pyridine rings, resulting in the formation of a two-dimensional network. Extensive hydrogen-bonding interactions lead to the formation of a three-dimensional supramolecular network.

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3

Wang, Yi, et Helen Stoeckli-Evans. « The inner-salt zwitterion, the dihydrochloride dihydrate and the dimethyl sulfoxide disolvate of 3,6-bis(pyridin-2-yl)pyrazine-2,5-dicarboxylic acid ». Acta Crystallographica Section C Crystal Structure Communications 68, n^o 11 (1 octobre 2012) : o431—o435. http://dx.doi.org/10.1107/s0108270112039534.

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In the inner-salt zwitterion of 3,6-bis(pyridin-2-yl)pyrazine-2,5-dicarboxylic acid, (I), namely 5-carboxy-3-(pyridin-1-ium-2-yl)-6-(pyridin-2-yl)pyrazine-2-carboxylate, [C16H10N4O4, (Ia)], the pyrazine ring has a twist–boat conformation. The opposing pyridine and pyridinium rings are almost perpendicular to one another, with a dihedral angle of 80.24 (18)°, and are inclined to the pyrazine mean plane by 36.83 (17) and 43.74 (17)°, respectively. The carboxy and carboxylate groups are inclined to the mean plane of the pyrazine ring by 43.60 (17) and 45.46 (17)°, respectively. In the crystal structure, the molecules are linkedviaN—H...O and O—H...O hydrogen bonds, leading to the formation of double-stranded chains propagating in the [010] direction. On treating (Ia) with aqueous 1 MHCl, the diprotonated dihydrate form 2,2′-(3,6-dicarboxypyrazine-2,5-diyl)bis(pyridin-1-ium) dichloride dihydrate [C16H12N4O42+·2Cl−·2H2O, (Ib)] was obtained. The cation lies about an inversion centre. The pyridinium rings and carboxy groups are inclined to the planar pyrazine ring by 55.53 (9) and 19.8 (2)°, respectively. In the crystal structure, the molecules are involved in N—H...Cl, O—H...Owaterand Owater—H...Cl hydrogen bonds, leading to the formation of chains propagating in the [010] direction. When (Ia) was recrystallized from dimethyl sulfoxide (DMSO), the DMSO disolvate 3,6-bis(pyridin-2-yl)pyrazine-2,5-dicarboxylic acid dimethyl sulfoxide disolvate [C16H10N4O4·2C2H6OS, (Ic)] of (I) was obtained. Here, the molecule of (I) lies about an inversion centre and the pyridine rings are inclined to the planar pyrazine ring by only 23.59 (12)°. However, the carboxy groups are inclined to the pyrazine ring by 69.0 (3)°. In the crystal structure, the carboxy groups are linked to the DMSO molecules by O—H...O hydrogen bonds. In all three crystal structures, the presence of nonclassical hydrogen bonds gives rise to the formation of three-dimensional supramolecular architectures.

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4

Martinez-Martin, Paloma, Josefina Perles et Juan Carlos Rodriguez-Ubis. « Crystal Structure Dependence of the Energy Transfer from Tb(III) to Yb(III) in Metal–Organic Frameworks Based in Bispyrazolylpyridines ». Crystals 10, n^o 2 (27 janvier 2020) : 69. http://dx.doi.org/10.3390/cryst10020069.

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Luminescent mixed lanthanide metal−organic framwork (MOF) materials have been prepared from two polyheterocyclic diacid ligands, 2,6-bis(3-carboxy-1-pyrazolyl)pyridine and 2,6-bis(4-carboxy-1-pyrazolyl)pyridine. The crystal structures of the two organic molecules are presented together with the structures for the MOFs obtained by hydrothermal synthesis either with Yb(III) or mixed Tb(III)/Yb(III) ions. Different coordination architectures result from each ligand, revealing also important differences between the lanthanides. The mixed lanthanide metal−organic frameworks also present diverse luminescent behavior; in the case of 2,6-bis(4-carboxy-1-pyrazolyl)pyridine, where no coordinated water is present in the metal environment, Tb(III) and Yb(III) characteristic emission is observed by excitation of the bispyrazolylpyridine chromophore.

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5

Voronkov, Mikhail G., Ekaterina A. Grebneva, Aleksandr I. Albanov, Olga M. Trofimova, Tamara N. Aksamentova, Nina N. Chipanina, Anastasiya S. Soldatenko et Nikolay F. Chernov. « The synthesis and structure of bis(pyridine-2-carboxy)difluoro(λ6)- and bis(pyridine-2-carboxy)fluorophenyl(λ5)siliconium ». Arkivoc 2011, n^o 8 (25 mars 2011) : 163–71. http://dx.doi.org/10.3998/ark.5550190.0012.812.

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6

Delarge, J., et C. L. Lapiere. « Synthèses dans la Série des Acides Pyridine-Carboxy-Sulfoniques et Pyridine Disulfoniques ». Bulletin des Sociétés Chimiques Belges 75, n^o 5-6 (2 septembre 2010) : 321–27. http://dx.doi.org/10.1002/bscb.19660750507.

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7

Niiyama, Kenji, Toshiaki Mase, Hirobumi Takahashi, Akira Naya, Kasumi Katsuki, Toshio Nagase, Satoshi Ito et al. « 6-Carboxy-5,7-diarylcyclopenteno[1,2-b]pyridine derivatives ». Bioorganic & ; Medicinal Chemistry 10, n^o 8 (août 2002) : 2461–70. http://dx.doi.org/10.1016/s0968-0896(02)00122-0.

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8

Amr, Abd El-Galil E., Ashraf M. Mohamed et Alhussein A. Ibrahim. « Synthesis of Some New Chiral Tricyclic and Macrocyclic Pyridine Derivatives as Antimicrobial Agents ». Zeitschrift für Naturforschung B 58, n^o 9 (1 septembre 2003) : 861–68. http://dx.doi.org/10.1515/znb-2003-0908.

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A series of chiral macrocyclic pyridines has been prepared starting from N2,N2-(pyridine- 2,6-dicarbonyl)diamino acid hydrazides (2a-c) and N,N-bis-(1-carboxy-2-substituted)-2,6- diaminocarbonyl)pyridines (3a,b). The coupling of (2a-c) with 2,6-pyridine dicarbonyldichloride (4) gave the compounds (5a-c). Compounds 2a-c were coupled with 2,6-diacetylpyridine (6) to yield compounds (7a-c) and with heterocyclic aldehydes (8) or (10) to give the compounds (9a-c) or (11a-c). In addition, the hydrazides (2a-c) were reacted with diformylcalix[4]arene 12 to afford the macrocyclic calix[4]arene hydrazone derivatives (13a-c) in reasonable yields. Finally, reaction of diaminocalix-[4]arene derivatives (14a,b) with hydrazides 2a,b or acids (3a,b), using azide or mixed anhydride methods afforded macrocyclic calix[4]arene derivatives 15a,b and 16a,b, respectively. The structure assignments of the new compounds are based on chemical and spectroscopic evidence. The biological activity screening tests showed that many of the obtained compounds exhibit high antimicrobial activity comparable to ampicillin and chloramphenicol which are used as reference compounds.

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9

Hakimi, Mohammad, Fereshteh Sadeghi, Nourollah Feizi, Keyvan Moeini, Monika Kučeráková et Michal Dušek. « Investigation of the effect of the N-oxidation process on the interaction of selected pyridine compounds with biomacromolecules : structural, spectral, theoretical and docking studies ». Acta Crystallographica Section C Structural Chemistry 75, n^o 6 (22 mai 2019) : 750–57. http://dx.doi.org/10.1107/s2053229619006375.

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Two new N-oxide compounds, namely glycinium 2-carboxy-1-(λ1-oxidaneyl)-1λ4-pyridine-6-carboxylate–glycine–water (1/1/1), C2H6NO2 +·C7H4NO5 −·C2H5NO2·H2O or [(2,6-HpydcO)(HGLY)(GLY)(H2O)], 1, and methyl 6-carboxy-1-(λ1-oxidaneyl)-1λ4-pyridine-2-carboxylate, C8H7NO5 or 2,6-HMepydcO, 2, were prepared and identified by elemental analysis, FT–IR, Raman spectroscopy and single-crystal X-ray diffraction. The X-ray analysis of 1 revealed an ionic compound containing a 2,6-HpydcO− anion, a glycinium cation, a neutral glycine molecule and a water molecule. Compound 2 is a neutral compound with two independent units in its crystal structure. In addition to the hydrogen bonds, the crystal network is stabilized by π–π stacking interactions of the types pyridine–carboxylate and carboxylate–carboxylate. The thermodynamic stability and charge-distribution patterns for isolated molecules of 2,6-H2pydcO and 2,6-HMepydcO, and their two similar derivatives, pyridine-2,6-dicarboxylic acid (2,6-H2pydc) and dimethyl 1-(λ1-oxidaneyl)-1λ4-pyridine-2,6-dicarboxylate (2,6-Me2pydcO), were studied by density functional theory (DFT) and natural bond orbital (NBO) analysis, respectively. The ability of these compounds and their analogues to interact with nine selected biomacromolecules (BRAF kinase, CatB, DNA gyrase, HDAC7, rHA, RNR, TrxR, TS and Top II) was investigated using docking calculations.

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10

Smith, Graham, et Urs D. Wermuth. « 4-(4-Nitrobenzyl)pyridinium 3-carboxy-4-hydroxybenzenesulfonate ». Acta Crystallographica Section E Structure Reports Online 69, n^o 2 (9 janvier 2013) : o206. http://dx.doi.org/10.1107/s1600536813000093.

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In the title salt, C12H11N2O2+·C7H5O6S−, the dihedral angle between the benzene and pyridine rings in the 4-(4-nitrobenzyl)pyridinium cation is 82.7 (2)°. Within the anion there is an intramolecular hydroxy-O—H...O(carboxylic acid) bond. In the crystal, the cation forms a single N+—H...Osulfonatehydrogen bond with the anion. These cation–anion pairs interact through duplex anion carboxylic acid O—H...Osulfonatehydrogen bonds, giving a centrosymmetric cyclic association [graph setR22(16)]. The crystals studied were non-merohedrally twinned.

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11

Petrova, O. V., N. Sh Lebedeva, A. I. V’ugin, V. E. Maizlish et G. P. Shaposhnikov. « Crystal solvates of carboxy-substituted Zn(II) phthalocyaninates with pyridine ». Russian Journal of Coordination Chemistry 32, n^o 10 (octobre 2006) : 740–43. http://dx.doi.org/10.1134/s1070328406100071.

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12

Xing, Jianxin. « 3-(4-Pyridyl)benzoic acid ». Acta Crystallographica Section E Structure Reports Online 65, n^o 6 (14 mai 2009) : o1239. http://dx.doi.org/10.1107/s1600536809015530.

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The molecule of the title compound, C12H9NO2, is not planar, the benzene and pyridine rings making a dihedral angle of 32.14 (7)°. The carboxy group is slightly twisted with respect to the benzene ring by 11.95 (10)°. In the crystal structure, intermolecular O—H...N hydrogen bonds link neighboring molecules into infinite chains along thecaxis.

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13

Deacon, GB, et GN Stretton. « Organomercury Compounds. XXVII. The Synthesis and Properties of Some Carboxylato- and Carboxy-pyridinylmercurials ». Australian Journal of Chemistry 38, n^o 3 (1985) : 419. http://dx.doi.org/10.1071/ch9850419.

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Decarboxylation of mercuric pyridine-2,3-dicarboxylate in hot dimethyl sulfoxide or hexamethylphosphoramide gives a mixture of 2-carboxylatopyridin-3-ylmercury(II) (major product) and 3- carboxylatopyridin-2-ylmercury(II) (minor product). The mixture reacts ( i ) with acidified halide ions ( Cl - or I-) to yield a mixture of the corresponding carboxypyridinyl ( halogeno )mercury(II) derivatives, (ii) with tribromide ions to give the bromo ( carboxypyridinyl )mercury(ii) complexes, 3-bromopyridine-2-carboxylic acid, and 2-bromopyridine-3- carboxylic acid, and (iii) with iodide ions in hot aqueous acetic acid to yield bis (2-carboxypyridin-3-yl)mercury(II) hydrogen triiodomercurate (II). Solutions of the last compound in dimethyl sulfoxide deposit bis (2-carboxypyridin-3-yl)mercury(II). Reaction of pyridine-2,3-dicarboxylate ions with mercuric acetate in boiling aqueous acetic acid at pH 5.0-5.8 gives mercurated acetic acid as the sole organometallic product, and the reported1 decarboxylation yielding 3-carboxylatopyridin-2-ylmercury(II) is not observed.

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14

Tutughamiarso, Maya, Thorsten Pisternick et Ernst Egert. « Pseudopolymorphs of chelidamic acid and its dimethyl ester ». Acta Crystallographica Section C Crystal Structure Communications 68, n^o 9 (1 août 2012) : o344—o350. http://dx.doi.org/10.1107/s0108270112031691.

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Different tautomeric and zwitterionic forms of chelidamic acid (4-hydroxypyridine-2,6-dicarboxylic acid) are present in the crystal structures of chelidamic acid methanol monosolvate, C7H5NO5·CH4O, (Ia), dimethylammonium chelidamate (dimethylammonium 6-carboxy-4-hydroxypyridine-2-carboxylate), C2H8N+·C7H4NO5−, (Ib), and chelidamic acid dimethyl sulfoxide monosolvate, C7H5NO5·C2H6OS, (Ic). While the zwitterionic pyridinium carboxylate in (Ia) can be explained from the pKavalues, a (partially) deprotonated hydroxy group in the presence of a neutral carboxy group, as observed in (Ib) and (Ic), is unexpected. In (Ib), there are two formula units in the asymmetric unit with the chelidamic acid entities connected by a symmetric O—H...O hydrogen bond. Also, crystals of chelidamic acid dimethyl ester (dimethyl 4-hydroxypyridine-2,6-dicarboxylate) were obtained as a monohydrate, C9H9NO5·H2O, (IIa), and as a solvent-free modification, in which both ester molecules adopt the hydroxypyridine form. In (IIa), the solvent water molecule stabilizes the synperiplanar conformation of both carbonyl O atoms with respect to the pyridine N atom by two O—H...O hydrogen bonds, whereas an antiperiplanar arrangement is observed in the water-free structure. A database study andab initioenergy calculations help to compare the stabilities of the various ester conformations.

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15

Syrota, Natalia O., Sergiy V. Kemskiy, Lesya M. Saliyeva et Mykhailo V. Vovk. « 1,2,3-Triazole-4(5)-amines – Convenient Synthetic Blocks for the Construction of Triazolo-Annulated Heterocycles ». Journal of Organic and Pharmaceutical Chemistry 20, n^o 2 (20 juillet 2022) : 27–51. http://dx.doi.org/10.24959/ophcj.22.258512.

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Aim. To analyze and summarize the synthetic potential of 1,2,3-triazole-4(5)-amines as efficient building blocks in the synthesis of triazolo-annulated pyridine, azine and azepine systems.Results and discussion. Original literature sources revealing the synthetic potential of 4(5)-amino functionalized 1,2,3-triazoles as convenient and available building blocks for the preparation of triazolo-annulated pyridines, azines and azepines were analyzed and systematized. Condensation of 1,2,3-triazole-4(5)-amines with methylene active compounds was shown to be a powerful tool for the synthesis of versatile triazolo[4,5-b]pyridines. In turn, the cyclocondensation based on 5-amino-1,2,3-triazole-4-carboxylic acids and their structurally modified derivatives was proven to be a general way for obtaining a number of triazolo[4,5-d]pyrimidine systems. Few representatives of triazolo-annulated pyridazines, 1,3-oxazines and 1,3-thiazines were synthesized by the intramolecular cyclization of the corresponding 4-aryl(carboxy-, aminomethyl)-5-amino-1,2,3-triazoles. The cyclocondensation involving 4,5-diamino-, 4-carbofunctionalized 5-amino-1,2,3-triazoles and 4-amino-5-thiocarboxamido-1,2,3-triazoles was successful for the construction of di-, oxa- and thiazepino-annulated triazoles.Conclusions. The analysis, systematization and summary of the literature regarding the synthetic potential of 1,2,3-triazole-4(5)-amines conclusively demonstrate that these structures are easily available and convenient molecular blocks for the construction of triazolo-annulated pyridine, azine and azepine systems that are important for synthetic and biomedical research.

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Chen, Shuqi, et Bernard L. Flynn. « Iodocyclisation of Electronically Resistant Alkynes : Synthesis of 2-Carboxy (and sulfoxy)-3-iodobenzo[b]thiophenes ». Australian Journal of Chemistry 74, n^o 1 (2021) : 65. http://dx.doi.org/10.1071/ch20218.

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The iodocyclisation of alkynes bearing tethered nucleophiles is a highly effective method for the construction and diversification of heterocycles. A key limitation to this methodology is the 5-endo-dig iodocyclisation of alkynes that have an unfavourable electronic bias for electrophilic cyclisation. These tend to direct electrophilic attack of the iodonium atom to the wrong carbon for cyclisation, thus favouring competing addition reactions. Using our previously determined reaction conditions for the 5-endo-dig iodocyclisations of electronically resistant alkynes, we have achieved efficient synthetic access to 2-carboxy (and sulfoxy)-3-iodobenzo[b]thiophenes. The corresponding benzo[b]furans and indoles were not accessible under these conditions. This difference may arise due to the availability of a radical mechanism in the case of iodobenzo[b]thiophenes. The 2-carboxy functionality of the iodocyclised products can be further employed in iterative alkyne-coupling iodocyclisation reactions, where the carboxy group or an imine (Schiff base) partakes in a second iodocyclisation to generate a lactone or pyridine ring.

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Smith, Graham, et Urs D. Wermuth. « Crystal structures and hydrogen bonding in the proton-transfer salts of nicotine with 3,5-dinitrosalicylic acid and 5-sulfosalicylic acid ». Acta Crystallographica Section E Structure Reports Online 70, n^o 11 (29 octobre 2014) : 430–34. http://dx.doi.org/10.1107/s1600536814023253.

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The structures of the 1:1 anhydrous salts of nicotine (NIC) with 3,5-dinitrosalicylic acid (DNSA) and 5-sulfosalicylic acid (5-SSA), namely (1R,2S)-1-methyl-2-(pyridin-3-yl)-1H-pyrrolidin-1-ium 2-carboxy-4,6-dinitrophenolate, C10H15N2+·C7H3N2O7−, (I), and (1R,2S)-1-methyl-2-(pyridin-3-yl)-1H-pyrrolidin-1-ium 3-carboxy-4-hydroxybenzenesulfonate, C10H15N2+·C7H5O6S−, (II), are reported. The asymmetric units of both (I) and (II) comprise two independent nicotinium cations (CandD) and either two DNSA or two 5-SSA anions (AandB), respectively. One of the DNSA anions shows a 25% rotational disorder in the benzene ring system. In the crystal of (I), inter-unit pyrrolidinium N—H...Npyridinehydrogen bonds generate zigzag NIC cation chains which extend alonga, while the DNSA anions are not involved in any formal inter-species hydrogen bonding but instead form π–π-associated stacks which are parallel to the NIC cation chains alonga[ring-centroid separation = 3.857 (2) Å]. Weak C—H...O interactions between chain substructures give an overall three-dimensional structure. In the crystal of (II),AandBanions form independent zigzag chains withCandDcations, respectively, through carboxylic acid O—H...Npyridinehydrogen bonds. These chains, which extend alongb, are pseudocentrosymmetrically related and give π–π interactions between the benzene rings of anionsAandBand the pyridine rings of the NIC cationsCandD, respectively [ring centroid separations = 3.6422 (19) and 3.7117 (19) Å]. Also present are weak C—H...O hydrogen-bonding interactions between the chains, giving an overall three-dimensional structure.

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18

Ribeiro da Silva, Maria D. M. C., M. Agostinha, R. Matos, M. Cláudia Vaz, Luı́s M. N. B. F. Santos, G. Pilcher, W. E. Acree Jr. et Joyce R. Powell. « Enthalpies of combustion of the pyridine N-oxide derivatives : 4-methyl-, 3-cyano-, 4-cyano-, 3-hydroxy-, 2-carboxy-, 4-carboxy-, and 3-methyl-4-nitro, and of the pyridine derivatives : 2-carboxy-, and 4-carboxy-. The dissociation enthalpies of the N-O bonds ». Journal of Chemical Thermodynamics 30, n^o 7 (juillet 1998) : 869–78. http://dx.doi.org/10.1006/jcht.1998.0353.

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19

Li, Jun-Xia, Zhong-Xiang Du, Juan Wang et Xun Feng. « Two mononuclear zinc(II) complexes constructed by two types of phenoxyacetic acid ligands : syntheses, crystal structures and fluorescence properties ». Zeitschrift für Naturforschung B 74, n^o 11-12 (18 décembre 2019) : 839–45. http://dx.doi.org/10.1515/znb-2019-0147.

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AbstractTwo new mononuclear complexes, [Zn(3-Hcpa)2(H2O)4] (1) and [Zn(3,5,6-tcpa)2(H2O)4] [Zn(3,5,6-tcpa)2(H2O)2] (2) (3-H2cpa = 3-carboxy-phenoxyacetic acid, 3,5,6-Htcpa = 3,5,6-trichloro pyridine-2-oxyacetic acid), were synthesized and structurally characterized. The single-crystal X-ray diffraction analysis showed that in 1 the ZnII ion lies on an inversion center of an octahedron formed by four aqua ligands and two carboxy oxygen atoms of two unidentate 3-Hcpa− anions in trans-arrangement. Complex 2 is a co-crystal consisting of two discrete and stereochemically different complexes: one with an octahedrally, and the other a tetrahedrally coordinated zinc center. The six-coordination about the first ZnII ion comprises four oxygen atoms from water (H2O) molecules and two from the carboxy groups of monodentate trans-related 3,5,6-tcpa− ligands. The four-coordination about the second ZnII ion is comprised of two H2O ligands and two unidentate carboxy oxygen atoms from 3,5,6-tcpa− ligands. O–HLO hydrogen bond and/or ClLCl halogen bond interactions play an important part in construction of the three-dimensional (3D) networks for 1 and 2. The photoluminescence spectra reveal that both 1 and 2 display luminescent properties in the violet region.

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Mukul, M. K., et P. K. Srivastava. « Synthesis and Characterization of Easily Processable Polyaramides Containing Pendent Diamantan Moiety in the Main Chain ». E-Journal of Chemistry 5, n^o 2 (2008) : 257–62. http://dx.doi.org/10.1155/2008/573097.

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Three new polyamides were synthesized by direct polycondensation of 1-6 bis(carboxy methyl diamantan with three different aromatic amines in Nmethyl 2-pyrrolidine containing lithium chloride using triphenyl phosphate and pyridine as condensing agent. 1-6 bis(carboxy methyl)diamantan was prepared from 1-6 dibromo diamantan and structure was conformed by1H and13C NNR spectroscopy. A comparison of the effect for introducing bulky side group in the diamine contribution was evaluated. This polyamide had inherent viscosity of 0.57-1.18dL/g. It was found that all polyamides were soluble in polar aprotic solvents. Thermal stability of polymer was evaluated by TGA analysis. Molecular weights of all polyamides were determined by gel permeation chromatography. These have been found to be thermally stable up to 400°C with 1320% weight loss under nitrogen atmosphere.

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Deng, Yi-Fang, et Xue Nie. « Poly[[diaqua[μ2-3-carboxy-5-(pyridine-4-carboxamido)benzoato][μ4-5-(pyridine-4-carboxamido)isophthalato]cerium(III)] monohydrate] ». Acta Crystallographica Section E Structure Reports Online 68, n^o 5 (4 avril 2012) : m530. http://dx.doi.org/10.1107/s1600536812013402.

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Dayananda, A. S., Grzegorz Dutkiewicz, H. S. Yathirajan et Maciej Kubicki. « (R)-Doxylaminium (R,R)-tartrate ». Acta Crystallographica Section E Structure Reports Online 68, n^o 4 (14 mars 2012) : o1054—o1055. http://dx.doi.org/10.1107/s160053681200935x.

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In the title compound (systematic name: (R)-dimethyl{2-[1-phenyl-1-(pyridin-2-yl)ethoxy]ethyl}azanium (R,R)-3-carboxy-2,3-dihydroxypropanoate), C17H23N2O+·C4H5O6−, the doxylaminium cation is protonated at the N atom. The tartrate monoanions are linked by short, almost linear O—H...O hydrogen bonds into chains extended along [100]. These chains are interlinked by anion–pyridine O—H...N hydrogen bonds into a two-dimensional grid structure. WeakC—H...O interactions also play a role in the crystal packing. An intramolecular hydroxy–carboxylate O—H...O hydrogen bond influences the conformation of the anion: the hydrogen-bonded fragment is almost planar, the maximum deviation from the mean plane being 0.059 (14) Å. In the cation, the aromatic rings are almost perpendicular [dihedral angle = 84.94 (8)°] and the conformation of the O—C—C—N chain isgauche(−), the dihedral angle is −76.6 (2)°. The absolute configuration was assigned on the basis of known chirality of the parent compound.

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Sinaga, Cinthia Uly Hotnami, et Asep Wahyu Nugraha. « Determining the Most Stable Structure of Benzamided Derivatives Using Density Functional Theory (DFT) ». Indonesian Journal of Chemical Science and Technology (IJCST) 4, n^o 2 (23 août 2021) : 49. http://dx.doi.org/10.24114/ijcst.v4i2.27594.

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This study aims to determine the energy change ∆E and determine the most stable compound based on computation results using the Density Functional Theory (DFT) method. In determining the energy change ∆E and determining the most stable compound, computational chemical calculations were used using NWChem version 6.6 software with the DFT method with the B3LYP / 3-21G base set hybrid function, the results of the calculations were visualized using the Jmol software. The results of computational calculations on the compound Benzamide is 57467.3632844735 kJ / mol, (4 - chlorocarbonyl - benzial) - pyridine acid carbamics - 3 - ilmetyl ester is 641022.0125237265 kJ / mol, (4- phenylcarbamil benzyl) - pyridine acid carbamic - 3 - ilmetyl ester of 491144.0953277345 kJ / mol, [4- (2-nitro - phenyl carbamoyl) - benzyl] - pyridine acid carboxy - 3 - ilmetyl ester of 1031145,366027853 kJ / mol while for [4 - 2 (amino - phenyl carbamyl) - benzyl) - carboxylic acid - 3 - ilmetyl ester of -1034711.17423932 kJ / mol. Based on these data it can be concluded that [4 - 2 (amino - phenyl carbamyl) - benzyl) - carboxylic acid - 3 - ilmetyl ester is the most stable compound formed because of its lowest price (exothermic)

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Wang, Huimin, Xiaojun Gu, Bingbing Zhang et Haiquan Su. « (2,2′-Bipyridine-6,6′-dicarboxylato-κ3N,N′,O6)(6′-carboxy-2,2′-bipyridine-6-carboxylato-κ3N,N′,O6)cobalt(III) ». Acta Crystallographica Section E Structure Reports Online 68, n^o 4 (14 mars 2012) : m411—m412. http://dx.doi.org/10.1107/s1600536812009816.

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The CoIIIatom in the title compound, [Co(C12H6N2O4)(C12H7N2O4)], is six-coordinated in a distorted octahedral geometry by four N atoms and two O atoms of the chelating 2,2′-bipyridine-6,6′-dicarboxylate and 6′-carboxy-2,2′-bipyridine-6-carboxylate ligands. Intermolecular O—H...O hydrogen bonds and face-to-face π-stacking interactions [centroid–centroid distance = 3.6352 (16) Å] between inversion-related pyridine rings link adjacent mononuclear units into a two-dimensional supramolecular structure, and several intermolecular C—H...O interactions are also observed.

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Yang, Jin-Hua, Wei Li, Shao-Liang Zheng, Zhen-Li Huang et Xiao-Ming Chen. « A Two-Dimensional Layered Cadmium Polymer Featuring Cd4(μ-O)4 Cores and Fluorescent Emission ». Australian Journal of Chemistry 56, n^o 12 (2003) : 1175. http://dx.doi.org/10.1071/ch03195.

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A cadmium coordination complex featuring novel Cd4(μ-O)4 cores, [Cd2(Hbna)(opy)(H2O)2] (1) (H4bna=2,2′-dihydroxy-[1,1′]-binaphthalene-3,3′-dicarboxylate acid; Hopy=1H-pyridine-2-one), has been hydrothermally synthesized and characterized. The Hbna ligand here acts in an unprecedented chelating/tridentate coordination mode for two carboxy groups with an additional μ-O-bridging coordination mode for the ortho-hydroxy oxygen atom. A study of the physical properties of solid (1) at room temperature demonstrates that it exhibits a moderately strong fluorescent emission in the blue-green region (about 538 nm), which can be assigned to LMCT emission.

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Svete, Jurij, David Bevk, Renata Jakse, Amalija Colobic, Ljubo Golic, Anton Meden et Branko Stanovnik. « Synthesis of 5-Substituted Ethyl 3-Oxo-2H-pyrazolo[4,3-c]pyridine-7-carboxy-lates ». HETEROCYCLES 63, n^o 3 (2004) : 609. http://dx.doi.org/10.3987/com-03-9964.

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Scaffidi, Adrian, Brian W. Skelton, Robert V. Stick et Allan H. White. « The Synthesis of Some Oligopeptides Derived from Novel Carbohydrate α-Amino Acids ». Australian Journal of Chemistry 57, n^o 8 (2004) : 733. http://dx.doi.org/10.1071/ch04014.

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The attempted coupling of a carbohydrate α-azido acid with a carbohydrate α-amino ester in the presence of a diimide, hopefully to produce a dipeptide, yielded only the carboxylic anhydride. However, the combination of 4-toluenesulfonyl chloride in pyridine was successful, and four carbohydrate dipeptides were separately produced. One of these dipeptides was further transformed into a tripeptide, and another into a hexapeptide. A single-crystal X-ray structure is reported for (3S)-3-azido-3-C-carboxy-3-deoxy-1,2:5,6-di-O-isopropylidene-α-d-ribo-hexose, amide with (3S)-3-amino-3-deoxy-1,2:5,6-di-O-isopropylidene-3-C-methoxycarbonyl-α-d-ribo-hexose.

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Hancock, Robert D., Arthur E. Martell, Dian Chen, Ramunas J. Motekaitis et Derek McManus. « Design of ligands for the complexation of Fe(II)/Fe(III) in the catalytic oxidation of H2S to sulfur ». Canadian Journal of Chemistry 75, n^o 5 (1 mai 1997) : 591–600. http://dx.doi.org/10.1139/v97-070.

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Examination of the stability constants of Fe(II) and Fe(III) chelates of a wide variety of ligands that contain only acetate and amino groups shows a linear correlation. A separate linear correlation displaced toward the ferric ion was obtained for those ligands that contain more basic phenolate donor groups. The ligands of the latter group generally are unsuited to the oxidation of H2S to sulfur, while ligands in the first correlation are suitable for that purpose. Ligands that do not contain α-methylene groups are relatively resistant to oxidative degradation. Molecular mechanics is employed to compare the Fe(III) complexes of three such ligands, dipicolinic acid (DIPIC), pyridine-2-phosphonic-6-carboxylic acid (2PP6C), and 2-carboxy-8-hydroxyquinoline (CHOX). The calculations show that there is considerable strain in the formation of the Fe(II) and Fe(III) complexes of these ligands, both with respect to the O–O distance and the O-Fe-O angle. The relatively high stability of the CHOX complex compared to that of DIPIC, therefore, is due mainly to the higher basicity of the phenolate oxygen compared to the carboxylate groups of DIPIC. The higher stability of the Fe(III) complex of 2PP6C relative to that of DIPIC is due to the higher basicity and charge of the phosphonate group compared to a carboxylate group of DIPIC that it replaces. In spite of the lack of α-methylene groups in CHOX, the ligand undergoes rapid oxidative degradation when its iron chelate is used as a catalyst for the oxidation of H2S to sulfur by air. However, the oxidation products were found to also be effective catalysts for this process. Keywords: hydrogen sulfide, oxidation catalysis, dipicolinic acid, pyridine-2-phosphonic-6-carboyxlic acid, 2-carboxy-8-hydroxyquinoline.

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Pellón, Roland F., Ramón Carrasco, Virgen Milián et Lorenzo Rodés. « Use of Pyridine as Cocatalyst for the Synthesis of 2-Carboxy Substituted Diphenylethers by Ullmann-Goldberg Condensation ». Synthetic Communications 25, n^o 7 (avril 1995) : 1077–83. http://dx.doi.org/10.1080/00397919508012670.

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Liu, Shiyong, Guangzhao Zhang et Ming Jiang. « Soluble graft-like complexes based on poly(4-vinyl pyridine) and carboxy-terminated polystyrene oligomers due to hydrogen bonding ». Polymer 40, n^o 19 (septembre 1999) : 5449–53. http://dx.doi.org/10.1016/s0032-3861(99)00101-9.

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Zhang, Li-Yang, Li-Ping Lu et Si-Si Feng. « A two-dimensional mixed-valence CuII/CuIcoordination polymer constructed from 2-(pyridin-3-yl)-1H-imidazole-4,5-dicarboxylate ». Acta Crystallographica Section C Structural Chemistry 72, n^o 8 (22 juillet 2016) : 652–57. http://dx.doi.org/10.1107/s205322961601161x.

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Coordination polymers are a thriving class of functional solid-state materials and there have been noticeable efforts and progress toward designing periodic functional structures with desired geometrical attributes and chemical properties for targeted applications. Self-assembly of metal ions and organic ligands is one of the most efficient and widely utilized methods for the construction of CPs under hydro(solvo)thermal conditions. 2-(Pyridin-3-yl)-1H-imidazole-4,5-dicarboxylate (HPIDC2−) has been proven to be an excellent multidentate ligand due to its multiple deprotonation and coordination modes. Crystals of poly[aquabis[μ3-5-carboxy-2-(pyridin-3-yl)-1H-imidazole-4-carboxylato-κ5N1,O5:N3,O4:N2]copper(II)dicopper(I)], [CuIICuI2(C10H5N3O4)2(H2O)]n, (I), were obtained from 2-(pyridin-3-yl)-1H-imidazole-4,5-dicarboxylic acid (H3PIDC) and copper(II) chloride under hydrothermal conditions. The asymmetric unit consists of one independent CuIIion, two CuIions, two HPIDC2−ligands and one coordinated water molecule. The CuIIcentre displays a square-pyramidal geometry (CuN2O3), with twoN,O-chelating HPIDC2−ligands occupying the basal plane in atransgeometry and one O atom from a coordinated water molecule in the axial position. The CuIatoms adopt three-coordinated Y-shaped coordinations. In each [CuN2O] unit, deprotonated HPIDC2−acts as anN,O-chelating ligand, and a symmetry-equivalent HPIDC2−ligand acts as an N-atom donorviathe pyridine group. The HPIDC2−ligands in the polymer serve as T-shaped 3-connectors and adopt a μ3-κ2N,O:κ2N′,O′:κN′′-coordination mode, linking one CuIIand two CuIcations. The Cu cations are arranged in one-dimensional –Cu1–Cu2–Cu3– chains along the [001] direction. Further crosslinking of these chains by HPIDC2−ligands along thebaxis in a –Cu2–HPIDC2−–Cu3–HPIDC2−–Cu1– sequence results in a two-dimensional polymer in the (100) plane. The resulting (2,3)-connected net has a (123)2(12)3topology. Powder X-ray diffraction confirmed the phase purity for (I), and susceptibilty measurements indicated a very weak ferromagnetic behaviour. A thermogravimetric analysis shows the loss of the apical aqua ligand before decomposition of the title compound.

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De Jongh, K. S., P. J. Schofield et M. R. Edwards. « Kinetic mechanism of sheep liver NADPH-dependent aldehyde reductase ». Biochemical Journal 242, n^o 1 (15 février 1987) : 143–50. http://dx.doi.org/10.1042/bj2420143.

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The kinetic mechanism of the major sheep liver aldehyde reductase (ALR1) was studied with three aldehyde substrates: p-nitrobenzaldehyde, pyridine-3-aldehyde and D-glucuronate. In each case the enzyme mechanism was sequential and product-inhibition studies were consistent with an ordered Bi Bi mechanism, with the coenzymes binding to the free enzyme. Binding studies were used to investigate the interactions of substrates, products and inhibitors with the free enzyme. These provided evidence for the binding of D-glucuronate, L-gulonate and valproate, as well as NADP+ and NADPH. The enzyme was inhibited by high concentrations of D-glucuronate in a non-competitive manner, indicating that this substrate was able to bind to the free enzyme and to the E X NADP+ complex at elevated concentrations. Although the enzyme was inhibited by high pyridine-3-aldehyde concentrations, there was no evidence for the binding of this substrate to the free enzyme. Sheep liver ALR1 was inhibited by the ionized forms of alrestatin, sorbinil, valproate, 2-ethylhexanoate and phenobarbitone, indicating the presence of an anion-binding site similar to that described for the pig liver enzyme, which interacts with inhibitors and substrates containing a carboxy group. Sorbinil, valproate and 2-ethylhexanoate inhibited the enzyme uncompetitively at low concentrations and non-competitively at high concentrations, whereas phenobarbitone and alrestatin were non-competitive and uncompetitive inhibitors respectively. The significance of these results with respect to inhibitor and substrate binding is discussed.

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Vazquez-Vuelvas, Oscar F., Julia V. Hernández-Madrigal, Armando Pineda-Contreras, Simón Hernández-Ortega, Reyna Reyes-Martínez et David Morales-Morales. « Exoconformers ofN-(pyridin-2-yl)- andN-(pyridin-3-yl)norbornene-5,6-dicarboximide crystals ». Acta Crystallographica Section C Structural Chemistry 71, n^o 3 (6 février 2015) : 175–80. http://dx.doi.org/10.1107/s2053229615001886.

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Two isomeric pyridine-substituted norbornenedicarboximide derivatives, namelyN-(pyridin-2-yl)-exo-norbornene-5,6-dicarboximide, (I), andN-(pyridin-3-yl)-exo-norbornene-5,6-dicarboximide, (II), both C14H12N2O4, have been crystallized and their structures unequivocally determined by single-crystal X-ray diffraction. The molecules consist of norbornene moieties fused to a dicarboximide ring substituted at the N atom by either pyridin-2-yl or pyridin-3-yl in ananticonfiguration with respect to the double bond, thus affordingexoisomers. In both compounds, the asymmetric unit consists of two independent molecules (Z′ = 2). In compound (I), the pyridine rings of the two independent molecules adopt different conformations,i.e. synandanti, with respect to the methylene bridge. The intermolecular contacts of (I) are dominated by C—H...O interactions. In contrast, in compound (II), the pyridine rings of both molecules have ananticonformation and the two independent molecules are linked by carbonyl–carbonyl interactions, as well as by C—H...O and C—H...N contacts.

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Amr, Abd, Mohamed Abo-Ghalia, Gaber Moustafa, Mohamed Al-Omar, Eman Nossier et Elsayed Elsayed. « Design, Synthesis and Docking Studies of Novel Macrocyclic Pentapeptides as Anticancer Multi-Targeted Kinase Inhibitors ». Molecules 23, n^o 10 (20 septembre 2018) : 2416. http://dx.doi.org/10.3390/molecules23102416.

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A series of macrocyclic pyrido-pentapeptide candidates 2–6 were synthesized by using N,N-bis-[1-carboxy-2-(benzyl)]-2,6-(diaminocarbonyl)pyridine 1a,b as starting material. Structures of the newly synthesized compounds were established by IR, 1H and 13C-NMR, and MS spectral data and elemental analysis. The in-vitro cytotoxicity activity was investigated for all compounds against MCF-7 and HepG-2 cell lines and the majority of the compounds showed potent anticancer activity against the tested cell lines in comparison with the reference drugs. Out of the macrocyclic pyrido-pentapeptide based compounds, 5c showed encouraging inhibitory activity on MCF-7 and HepG-2 cell lines with IC50 values 9.41 ± 1.25 and 7.53 ± 1.33 μM, respectively. Interestingly, 5c also demonstrated multitarget profile and excellent inhibitory activity towards VEGFR-2, CDK-2 and PDGFRβ kinases. Furthermore, molecular modeling studies of the compound 5c revealed its possible binding modes into the active sites of those kinases.

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Brown, Alistair K., Ahmed K. B. Aljohani, Fatimah M. A. Alsalem, Joseph L. Broadhead, Jason H. Gill, Yucheng Lu et Jonathan D. Sellars. « Identification of Substituted Amino Acid Hydrazides as Novel Anti-Tubercular Agents, Using a Scaffold Hopping Approach ». Molecules 25, n^o 10 (21 mai 2020) : 2387. http://dx.doi.org/10.3390/molecules25102387.

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Discovery and development of new therapeutic options for the treatment of Mycobacterium tuberculosis (Mtb) infection, particularly drug-resistant strains, are urgently required to tackle the global burden of this disease. Herein, we reported the synthesis of a novel series of N-substituted amino acid hydrazides, utilising a scaffold hopping approach within a library of anti-tubercular agents. Efficacy and selectivity were evaluated against three strains of Mtb (wild-type, isoniazid-resistant and rifampicin-resistant), and cytotoxicity against macrophages in vitro. The antibacterial activity and therapeutic index of these molecules were significantly affected by modifications with the N-substituents. Introduction of a 3,5-dinitroaryl moiety demonstrated enhanced antibacterial activity against all three strains of Mtb. In contrast, the inclusion of an imidazo [1,2-a]pyridine-3-carboxy moiety resulted in enhanced activity towards isoniazid mono-resistant Mtb relative to wild-type Mtb. Consequently, this scaffold hopping approach showed significant promise for exemplification of novel molecules with specific activity profiles against drug-resistant tuberculosis.

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Liu, Wei, et Xia Li. « Aqua[2,2′-(propane-1,3-diyl)bis(5-carboxy-1H-imidazole-4-carboxylato)-κ4N3,O4:N3′,O4′](pyridine-κN)cobalt(II)–4,4′-bipyridine (1/1) ». Acta Crystallographica Section E Structure Reports Online 68, n^o 8 (25 juillet 2012) : m1109—m1110. http://dx.doi.org/10.1107/s1600536812029856.

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In the title compound, [Co(C13H10N4O8)(C5H5N)(H2O)]·C10H8N2, the asymmetric unit comprises half a CoIIcomplex located on a mirror plane and half a cocrystallized molecule of 4,4′-bipyridine located on an inversion center. The CoIIion is six coordinate, with distorted octahedral geometry, ligated by two N atoms and two O atoms from a 2,2′-(propane-1,3-diyl)bis(5-carboxy-1H-imidazole-4-carboxylate) dianion, one N atom from a pyridine molecule and one coordinating water molecule. The Co—O bond lengths range from 2.076 (2) to 2.1441 (15) Å, while the Co—N bond lengths are 2.138 (3) and 2.1515 (17) Å. A two-dimensional network of N—H...O and O—H...N hydrogen bonds stabilizes the crystal packing. There are π–π interactions between the bipyridine and imidazole rings [centroid–centroid distance = 3.7694 (4) Å]. The propane-1,3-diyl group is disordered over two conformations, with refined occupancies of 0.755 (8) and 0.245 (8).

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Koretsky, A. P., L. A. Katz et R. S. Balaban. « Determination of pyridine nucleotide fluorescence from the perfused heart using an internal standard ». American Journal of Physiology-Heart and Circulatory Physiology 253, n^o 4 (1 octobre 1987) : H856—H862. http://dx.doi.org/10.1152/ajpheart.1987.253.4.h856.

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Mitochondrial reduced nicotinamide adenine dinucleotide (NADH) is a key intermediate in energy metabolism in the heart, which can be qualitatively monitored using nondestructive surface fluorescence techniques. However, this optical technique is subject to artifacts from alterations in tissue absorbance, motion of the heart, and variations in excitation intensity. In this study rapid-scan fluorescence emission spectroscopy was used in conjunction with an internal fluorescence standard to compensate for these optical artifacts. The fluorescence spectra obtained from heart had a maximum at 460 nm and a shoulder at 415 nm. Dilution of heart homogenates resulted in a fluorescent spectrum characteristic of suspensions of mitochondria, indicating that absorption of fluorescence by tissue components produces an inner filter effect. This internal filter was characterized, and isobestic points with regard to O2 were found at 425 and 450 nm. Alterations in the inner filter effect due to changes in tissue oxygenation were eliminated by monitoring the NADH at 425 nm. Motion artifacts and excitation source fluctuations were corrected by loading heart cells with an internal fluorescent standard, 5(6)-carboxy-2',7'-dichlorofluorescein (ClCF). Motion of the heart and changes in excitation intensity altered the fluorescence detected from both NADH and ClCF. The use of the NADH-to-ClCF ratio detected at isobestic wavelengths (425 nm NADH and 520 nm ClCF) gives a relative measure of NADH fluorescence, which adequately compensates for both internal absorbance and motion artifacts.

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Song, Jiang-Feng, Ying-Ying Jia, Rui-Sha Zhou, Si-Zhe Li, Xiao-Min Qiu et Jie Liu. « Six new coordination compounds based on rigid 5-(3-carboxy-phenyl)-pyridine-2-carboxylic acid : synthesis, structural variations and properties ». RSC Advances 7, n^o 12 (2017) : 7217–26. http://dx.doi.org/10.1039/c6ra26966d.

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PELLON, R. F., R. CARRASCO, V. MILIAN et L. RODES. « ChemInform Abstract : Use of Pyridine as Cocatalyst for the Synthesis of 2-Carboxy- Substituted Diphenyl Ethers by Ullmann-Goldberg Condensation. » ChemInform 26, n^o 31 (17 août 2010) : no. http://dx.doi.org/10.1002/chin.199531103.

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Dibwe, Dya Fita, Saki Oba, Nire Takeishi, Toshihiro Sakurai, Takayuki Tsukui, Hitoshi Chiba et Shu-Ping Hui. « Food-Derived β-Carboline Alkaloids Ameliorate Lipid Droplet Accumulation in Human Hepatocytes ». Pharmaceuticals 15, n^o 5 (5 mai 2022) : 578. http://dx.doi.org/10.3390/ph15050578.

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Lipid droplet accumulation (LDA) in hepatocytes is the initial stage of nonalcoholic fatty liver disease (NAFLD). In the search for natural compounds for the prevention of NAFLD, a series of β-carboline alkaloid derivatives, inspired by flazin and its derivative, newly identified in Crassostrea gigas Thunberg. extracts, were examined for LDA inhibition (LDAI) activity in oleic acid–loaded hepatocytes (HepG2). Eight compounds with a piperidine or pyridine C-ring were chemically synthesized (1–8). Among them, compounds 2 and 4 (flazin) with a carboxy group at C-3 and furfuryl alcohol moiety at C-1 showed low cytotoxicity and they exhibited significant LDAI activity. Compound 2 with piperidine C-ring was identified for the first time in C. gigas extract, and ameliorated the lipid accumulation with the LDAI value of 25.4%. Active compounds 2 and 4 significantly inhibited triacylglycerol species accumulation in cells. These compounds upregulated ATGL and downregulated SREBP1, FASN, and SCD1 genes, suggesting that they activated lipolysis and suppressed lipogenesis, respectively. These results suggest that β-carboline alkaloids, especially compounds 2 and 4, might be potentially useful for preventing NAFLD.

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Tamminen, Jari, Erkki Kolehmainen, Mervi Haapala et Juha Linnanto. « Bile Acid-Piperazine Diamides : Novel Steroidal Templates in Syntheses of Supramolecular Hosts : Isomeric Pyridine-n-carboxy Containing Dimers and a Cholaphane ». Synthesis 2000, n^o 10 (2000) : 1464–68. http://dx.doi.org/10.1055/s-2000-7113.

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Zhang, Xiao-Yu, Hui-Fang Wen, Qing-Feng Yang, Rui-Sha Zhou et Jiang-Feng Song. « Eight new coordination polymers containing rigid 4-(4-carboxy-phenyl)-pyridine-2-carboxylic acid : Synthesis, structural diversity, fluorescence and magnetic properties ». Inorganica Chimica Acta 507 (juillet 2020) : 119600. http://dx.doi.org/10.1016/j.ica.2020.119600.

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Nakanishi, Takumi, et Osamu Sato. « Crystal structures of two nickel compounds comprising neutral NiIIhydrazone complexes and dicarboxylic acids ». Acta Crystallographica Section E Crystallographic Communications 73, n^o 2 (6 janvier 2017) : 103–6. http://dx.doi.org/10.1107/s2056989016020326.

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Two isostructural NiIIcompounds, bis{N-[1-(pyridin-2-yl-κN)ethylidene]pyridine-4-carbohydrazonato-κ2N′,O}nickel(II)–2,5-dichloroterephthalic acid (1/1), [Ni(C13H11N4O)2](C8H4Cl2O4), and bis{N-[1-(pyridin-2-yl-κN)ethylidene]pyridine-4-carbohydrazonato-κ2N′,O}nickel(II)–2,5-dibromoterephthalic acid (1/1), [Ni(C13H11N4O)2](C8H4Br2O4), were synthesized and their crystal structures determined. The pair ofN,N′,O-tridentateN-[1-(pyridin-2-yl-κN)ethyl]pyridine-4-carbohydrazonateLligands result in acis-NiO2N4octahedral coordination sphere for the metal ions. The asymmetric units consist of two half-molecules of the dicarboxylic acids, which are completed by crystallographic inversion symmetry. In the respective crystals, the 2,5-dichloroterephthalic acid (H2Cl2TPA,1-Cl) molecules form zigzag hydrogen-bonded chains with the [Ni(L)2] molecules, with the hydrogen-bond distances in1-Brslightly longer than those in1-Cl. The packing is consolidated by aromatic π–π stacking between the dicarboxylic acid molecules and terminal pyridine rings in [Ni(L)2] and short halogen–halogen interactions are also observed. The qualitative prediction of the H-atom position from the C—N—C angles of the terminal pyridine rings inLand the C—O distances in the carboxyl groups show that1-Cland1-Brare co-crystals rather than salts.

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Hong, Dong-Feng, Wen-Bo Guo et Wei-Dong Yin. « Crystal structure of poly[(μ2-2-carboxy-5-nitroisophthalato-κ2O:O′)-(μ2-4-((1H-imidazol-1-yl)methyl)pyridine-κ2N:N′)zinc(II)], C18H12N4O8Zn ». Zeitschrift für Kristallographie - New Crystal Structures 233, n^o 6 (27 novembre 2018) : 1035–36. http://dx.doi.org/10.1515/ncrs-2018-0156.

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Maslehat, Sholeh, Soroush Sardari et Mahboube Ganji Arjenaki. « Frequency and Importance of Six Functional Groups that Play a Role in Drug Discovery ». Biosciences, Biotechnology Research Asia 15, n^o 3 (27 septembre 2018) : 541–48. http://dx.doi.org/10.13005/bbra/2659.

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Small molecules are composed of chemical functional groups; they are sets of connected atoms or atom groups that determine properties and reactivity of the parent molecule. DrugBank is a rich source of information that containing molecular data about small molecules, their mechanisms, pharmaceutical interaction and targets. In this study, After collecting data of small drug molecules from DrugBank database and classifying them in different categories based on their mechanism of action, the therapeutic properties of the molecules were recorded. Finally, the functional group from the pharmaceutical structures were elucidated and registered for each group. The functional groups were divided into five distinct groups in drug design, and a correlation between identified functional group to pharmaceutical structure were indicated according to the classified functional groups of small molecule and drug categories; then defined their frequency in categories, at high abundant functional group present in categories reported. The most frequent rings were benzene and cyclohexane; the common acid functionality had been acetate (carboxy-); three most repeated saturated heterocyles are piperidine, piperazine and azetidine; among the unsaturated heterocyles, pyridine, imidazole and indole are noticed; This database, that may be guidance for researchers with the aim at designing new drugs.

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Samshuddin, Seranthimata, Jerry P. Jasinski, Ray J. Butcher, Elizabeth A. Neuhardt, Badiadka Narayana, Hemmige S. Yathirajan et Christopher Glidewell. « Three closely-related cyclohexanols (C35H27X2N3O3;X= F, Cl or Br) : similar molecular structures but different crystal structures ». Acta Crystallographica Section C Structural Chemistry 70, n^o 10 (28 septembre 2014) : 953–59. http://dx.doi.org/10.1107/s2053229614019937.

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Three highly-substituted cyclohexanol derivatives have been prepared from 2-acetylpyridine and 4-halogenobenzaldehydes under mild conditions. (1RS,2SR,3SR,4RS,5RS)-3,5-Bis(4-fluorophenyl)-2,4-bis(pyridine-2-carbonyl)-1-(pyridin-2-yl)cyclohexanol, C35H27F2N3O3, (I), (1RS,2SR,3SR,4RS,5RS)-3,5-bis(4-chlorophenyl)-2,4-bis(pyridine-2-carbonyl)-1-(pyridin-2-yl)cyclohexanol acetone 0.951-solvate, C35H27Cl2N3O3·0.951C3H6O, (II), and (1RS,2SR,3SR,4RS,5RS)-3,5-bis(4-bromophenyl)-2,4-bis(pyridine-2-carbonyl)-1-(pyridin-2-yl)cyclohexanol, C35H27Br2N3O3, (III), all crystallize in different space groups,viz. Pbca,Fdd2 andP\overline{1}, respectively. In compound (II), the acetone molecule is disordered over two sets of atomic sites having occupancies of 0.690 (13) and 0.261 (13). Each of the cyclohexanol molecules contains an intramolecular O—H...N hydrogen bond and their overall molecular conformations are fairly similar. The molecules of (I) are linked by two independent C—H...O hydrogen bonds to form aC(5)C(10)[R22(15)] chain of rings, and those of (III) are linked by a combination of C—H...O and C—H...N hydrogen bonds, forming a chain of alternatingR22(16) andR22(18) rings. The cyclohexanol molecules in (II) are linked by a single C—H...N hydrogen bond to form simpleC(4) chains and these chains are linked by a π–π stacking interaction to form sheets, to which the disordered acetone molecules are weakly linkedviaa number of C—H...O contacts.

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Li, Bin, Nana Shen, Xinying Zhang et Xuesen Fan. « Synthesis of fused imidazo[1,2-a]pyridines derivatives through cascade C(sp2)–H functionalizations ». Organic & ; Biomolecular Chemistry 17, n^o 41 (2019) : 9140–50. http://dx.doi.org/10.1039/c9ob01744e.

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An efficient and convenient synthesis of fused imidazo[1,2-a]pyridine derivatives from the cascade reactions of 2-arylimidazo[1,2-a]pyridines with a-diazo carbonyl compounds via Rh(iii)-catalyzed C(sp²)–H functionalization/annulation is presented.

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Borzak, S., R. A. Kelly, B. K. Kramer, Y. Matoba, J. D. Marsh et M. Reers. « In situ calibration of fura-2 and BCECF fluorescence in adult rat ventricular myocytes ». American Journal of Physiology-Heart and Circulatory Physiology 259, n^o 3 (1 septembre 1990) : H973—H981. http://dx.doi.org/10.1152/ajpheart.1990.259.3.h973.

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Quantitation of Ca+ and H+ activities within cells using presently available fluorescent probes is optimal when the fluorescence signal is calibrated in situ after each experiment. Fura-2 and 2',7'-bis(2-carboxy-ethyl)-5,6-carboxyfluoroscein (BCECF) are difficult to calibrate in freshly dissociated adult cardiac myocytes because calibration procedures produce cellular hypercontracture. In situ calibration was accomplished in rat ventricular cells by saturating fura-2 with La3+, an agent known to produce myocardial relaxation. Since fura-2 has different spectral properties when complexed with La3+ than with Ca2+, scaling factors were defined in vitro and then verified by experiments in cultured neonatal myocytes. In adult rat myocytes using the La3+ method, intracellular Ca2+ concentration ([Ca2+]i) was 131 +/- 47 nM (n = 14) in quiescent cells; diastolic [Ca2+]i and systolic [Ca2+]i in myocytes stimulated at 1 Hz were 140 +/- 56 and 1,088 +/- 211 nM (n = 5), respectively. BCECF fluorescence was calibrated in situ by a method that prevented cellular hypercontracture and reported a pH value of 7.10 +/- 0.10 in cells stimulated at 1.5 Hz. An additional advantage of both methods is that the buffers employed prevented large changes in the redox state of intracellular pyridine nucleotides, thus preventing a change in cellular autofluorescence during the calibration procedure.

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Canonne, P., et M. Belley. « Étude de l'action des organomagnésiens sur les dérivés carboxyliques de la pyridine ». Canadian Journal of Chemistry 65, n^o 8 (1 août 1987) : 1885–90. http://dx.doi.org/10.1139/v87-316.

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Reactions of Grignard reagents with pyridinecarboxylic esters 1, 2, pyridine-2-carboxylic acid (3), and 2,3-pyridinedicarboxylic acid anhydride (5) show regioselectivity at the carbonyl in position 2. This is exemplified by an efficient synthesis of 7,7-dialkylated-7H-furo[3,4-b]-substituted pyridin-5-ones.

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Yang, Li-Zi, Jun Wang, Alexander M. Kirillov, Wei Dou, Cong Xu, Ran Fang, Cai-Ling Xu et Wei-Sheng Liu. « 2D lanthanide MOFs driven by a rigid 3,5-bis(3-carboxy-phenyl)pyridine building block : solvothermal syntheses, structural features, and photoluminescence and sensing properties ». CrystEngComm 18, n^o 34 (2016) : 6425–36. http://dx.doi.org/10.1039/c6ce00885b.

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