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Journal articles on the topic 'Pyridine-Pyrazole'

Author: Grafiati

Published: 4 June 2021

Last updated: 2 February 2022

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1

Senthil Kumar, Kuppusamy, Bernhard Schäfer, Sergei Lebedkin, Lydia Karmazin, Manfred M. Kappes, and Mario Ruben. "Highly luminescent charge-neutral europium(iii) and terbium(iii) complexes with tridentate nitrogen ligands." Dalton Transactions 44, no. 35 (2015): 15611–19. http://dx.doi.org/10.1039/c5dt02186c.

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We report the synthesis and efficient photoluminescence of charge-neutral lanthanide (Ln = Eu<sup>3+</sup> and Tb<sup>3+</sup>) complexes based on pyrazole–pyridine–tetrazole and pyrazole–pyridine–triazole ligands.

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2

Rao, H. Surya Prakash, Ramalingam Gunasundari, and Jayaraman Muthukumaran. "Crystal structure analysis of ethyl 3-(4-chlorophenyl)-1,6-dimethyl-4-methylsulfanyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate." Acta Crystallographica Section E Crystallographic Communications 76, no. 3 (2020): 443–45. http://dx.doi.org/10.1107/s2056989020002479.

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In the title compound, C18H18ClN3O2S, the dihedral angle between the fused pyrazole and pyridine rings is 3.81 (9)°. The benzene ring forms dihedral angles of 35.08 (10) and 36.26 (9)° with the pyrazole and pyridine rings, respectively. In the crystal, weak C—H...O hydrogen bonds connect molecules along [100].

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3

Guzei, Ilia A., Teddy T. Okemwa, and Stephen O. Ojwach. "2-[(3,5-Diphenyl-1H-pyrazol-1-yl)methyl]pyridine." Acta Crystallographica Section E Structure Reports Online 68, no. 4 (2012): o1190. http://dx.doi.org/10.1107/s1600536812011804.

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The title compound, C21H17N3, crystallizes with the phenyl ring in the 3-position coplanar with the pyrazole ring within 4.04 (5)°, whereas the phenyl ring in the 5-position forms a dihedral angle of 50.22 (3)° with the pyrazole ring. There is no ambiguity regarding the position of pyridine N atom, which could have exhibited disorder between theorthopositions of the ring.

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4

Hossain, Sayed Muktar, Gourab Kumar Dam, Sagarika Mishra, and Akhilesh Kumar Singh. "A nano-molar level fluorogenic and oxidation state-selective chromogenic dual reversible chemosensor for multiple targets, Cu2+/S2− and Fe3+/F− ions." New Journal of Chemistry 44, no. 35 (2020): 15186–94. http://dx.doi.org/10.1039/d0nj02777d.

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5

Stiborová, Marie, and Sylva Leblová. "Effect of heterocyclic compounds and 2-mercaptoethanol on rape alcohol dehydrogenase." Collection of Czechoslovak Chemical Communications 52, no. 8 (1987): 2107–13. http://dx.doi.org/10.1135/cccc19872107.

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Rape alcohol dehydrogenase (ADH) is inhibited by heterocyclic compounds with a five- to six-membered ring (imidazole, pyrazole, 4-methylpyrazole, 3-methylpyrazole, pyridine, nicotine amide) and by o-phenanthroline, a heterocyclic, polycyclic compound. Pyrazole and its derivatives, imidazole and pyridine, are competitive inhibitors with respect to ethanol. Nicotine amide and o-phenanthroline behave as mixed inhibitors (competitive – noncompetitive) with respect to the substrate. The addition of Zn2+-ions to the reaction medium interferes with the competition by o-phenanthroline. 4-Methylpyrazol

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6

Perrin, Monique, Alain Thozet, Pilar Cabildo, Rosa Ma Claramunt, Eduard Valenti, and José Elguero. "Molecular structure and tautomerism of 3,5-bis(4-methylpyrazol-1-yl)-4-methylpyrazole." Canadian Journal of Chemistry 71, no. 9 (1993): 1443–49. http://dx.doi.org/10.1139/v93-186.

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The title compound C12N6H14, 1, crystallizes in the space group P21/n (a = 8.222(2) Å, b = 27.336(8) Å, c = 5.574(2) Å, α = 90.00°, β = 100.97(4)°, γ = 90.00°), Z = 4, d = 1.308 g cm−3. The conformation about the N—C bonds linking the pyrazole rings can be defined as EZ, with "pyridine-like" nitrogen atoms in an anti disposition [Formula: see text] and "pyridine-like" and "pyrrole-like" nitrogen atoms in a syn disposition [Formula: see text] with regard to the central pyrazole. Intermolecular hydrogen bonds between the central and the terminal pyrazole ring of configuration Z form centrosymmet

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7

Xiang, Shiqun, Xiaofeng Zhang, Hui Chen, Yinghua Li, Weibin Fan, and Deguang Huang. "Copper(ii) facilitated decarboxylation for the construction of pyridyl–pyrazole skeletons." Inorganic Chemistry Frontiers 6, no. 9 (2019): 2359–64. http://dx.doi.org/10.1039/c9qi00599d.

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8

Jochim, Aleksej, and Christian Näther. "Formation of di- and polynuclear Mn(II) thiocyanate pyrazole complexes in solution and in the solid state." Zeitschrift für Naturforschung B 73, no. 11 (2018): 793–801. http://dx.doi.org/10.1515/znb-2018-0104.

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AbstractReaction of Mn(NCS)2with pyrazole leads to the formation of three compounds with the compositions Mn(NCS)2(pyrazole)4(1), [Mn(NCS)2]2(pyrazole)6(2) and Mn(NCS)2(pyrazole)2(3). Compound1, already reported in the literature, consists of discrete complexes, in which the Mn(II) cations are octahedrally coordinated by four pyrazole ligands and two terminally N-bonded thiocyanate anions. In compound2each of the two Mn(II) cations are coordinated octahedrally by three pyrazole ligands and one terminal as well as two bridging thiocyanate anions, which link the metal cations into dimers. In com

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9

Naskar, Barnali, Kinsuk Das, Ramij R. Mondal, et al. "A new fluorescence turn-on chemosensor for nanomolar detection of Al3+ constructed from a pyridine–pyrazole system." New Journal of Chemistry 42, no. 4 (2018): 2933–41. http://dx.doi.org/10.1039/c7nj03955g.

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10

Saha, Sayan, Avik De, Arijit Ghosh, et al. "Pyridine-pyrazole based Al(iii) ‘turn on’ sensor for MCF7 cancer cell imaging and detection of picric acid." RSC Advances 11, no. 17 (2021): 10094–109. http://dx.doi.org/10.1039/d1ra00082a.

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11

Yaghoubi Kalurazi, Sorayya, Kurosh Rad-Moghadam, and Shahram Moradi. "Efficient catalytic application of a binary ionic liquid mixture in the synthesis of novel spiro[4H-pyridine-oxindoles]." New Journal of Chemistry 41, no. 18 (2017): 10291–98. http://dx.doi.org/10.1039/c7nj01858d.

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Novel pyrazole-fused spiro[4H-pyridine-oxindoles] were synthesized under the catalysis of the binary ionic liquid mixture [1,1,3,3-tetramethylguanidinium chloride][1-methylimidazolium-3-sulfonate] in solvent-free conditions.

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12

Surya Prakash Rao, H., Ramalingam Gunasundari, and Jayaraman Muthukumaran. "Crystal structure analysis of ethyl 6-(4-methoxyphenyl)-1-methyl-4-methylsulfanyl-3-phenyl-1H-pyrazolo[3,4-b]pyridine-5-carboxylate." Acta Crystallographica Section E Crystallographic Communications 76, no. 8 (2020): 1209–12. http://dx.doi.org/10.1107/s2056989020008841.

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In the title compound, C24H23N3O3S, the dihedral angle between the fused pyrazole and pyridine rings is 1.76 (7)°. The benzene and methoxy phenyl rings make dihedral angles of 44.8 (5) and 63.86 (5)°, respectively, with the pyrazolo[3,4-b] pyridine moiety. An intramolecular short S...O contact [3.215 (2) Å] is observed. The crystal packing features C—H...π interactions.

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13

Chen, Chao, Liqian Zhou, Binbin Xie, et al. "Novel fast-acting pyrazole/pyridine-functionalized N-heterocyclic carbene silver complexes assembled with nanoparticles show enhanced safety and efficacy as anticancer therapeutics." Dalton Transactions 49, no. 8 (2020): 2505–16. http://dx.doi.org/10.1039/c9dt04751d.

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Four multi-nuclear silver complexes with pyrazole/pyridine-functionalized NHC ligands were synthesized and characterized. The anticancer activity of these silver complexes was investigated both in vitro and in vivo.

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14

Lan, Zheng, and Wang. "2-(3,5-Dimethyl-1H-pyrazol-1-yl)thiazolo[4,5-b]pyridine." Molbank 2019, no. 3 (2019): M1077. http://dx.doi.org/10.3390/m1077.

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The compound 2-(3,5-dimethyl-1H-pyrazol-1-yl)thiazolo[4,5-b]pyridine (1) was synthesized with a yield of 71% by the reaction of 1-(thiazolo[4,5-b]pyridine-2-yl)hydrazine and acetylacetone. The structure was characterized by a single-crystal X-ray structure determination as well as 1H and 13C{1H} NMR spectroscopy. X-ray crystallography on 1 confirms the molecule consists of a pyridine–thiazole moiety and the pyrazole ring, and all non-hydrogen atoms are planar.

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15

Baker, AT, DC Craig, G. Dong, and AD Rae. "Metal Complexes of 1,3-Bis(Pyridin-2-yl)pyrazole: Spectral, Magnetic and Structural Studies." Australian Journal of Chemistry 48, no. 6 (1995): 1071. http://dx.doi.org/10.1071/ch9951071.

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Bis(ligand)iron(II) and nickel(II) complexes of the asymmetric tridentate ligand 1,3-bis(pyridin-2-yl) pyrazole , L, have been prepared. The iron(II) complex, [FeL2] [PF6]2, is high-spin in the solid state over the temperature range 304-102 K, with a magnetic moment of 5.27 BM at room temperature. The crystal structure of bis (1,3-bis(pyridin-2-yl) pyrazole )iron(II) bis (hexafluorophosphate ) has been determined by single-crystal X-ray diffractometry. The compound crystallized as yellow prisms, with the structure being disordered in the tetragonal space group P421c with Z = 2. Crystal data a

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16

Grosche, Philipp. "Pyrazole, Pyridine and Pyridone Synthesis on Solid Support." Synthesis 1999, no. 11 (1999): 1961–70. http://dx.doi.org/10.1055/s-1999-3619.

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17

Zhao, Guo-zheng, and Ming Lu. "Comparative theoretical studies of energetic pyrazole-pyridine derivatives." Journal of Molecular Modeling 19, no. 8 (2013): 3403–10. http://dx.doi.org/10.1007/s00894-013-1869-x.

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18

Alsayari, Abdulrhman, Abdullatif Bin Muhsinah, Yahya I. Asiri, et al. "Arylhydrazono/Aryldiazenyl Pyrazoles: Green One-Pot Solvent-Free Synthesis and Anticancer Evaluation." Letters in Organic Chemistry 17, no. 10 (2020): 772–78. http://dx.doi.org/10.2174/1570178617666200320104923.

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The aim of this study was to synthesize and evaluate the biological activity of pyrazole derivatives, in particular, to perform a “greener” one-pot synthesis using a solvent-free method as an alternative strategy for synthesizing hydrazono/diazenyl-pyridine-pyrazole hybrid molecules with potential anticancer activity. Effective treatment for all types of cancers is still a long way in the future due to the severe adverse drug reactions and drug resistance associated with current drugs. Therefore, there is a pressing need to develop safer and more effective anticancer agents. In this context, s

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19

Sudheer, Sudheer, and M. A. Quraishi. "The corrosion inhibition effect of aryl pyrazolo pyridines on copper in hydrochloric acid system: computational and electrochemical studies." RSC Advances 5, no. 52 (2015): 41923–33. http://dx.doi.org/10.1039/c5ra03966e.

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The inhibition effect of three aryl pyrazole pyridine derivatives (APPs) against the corrosion of copper in 0.5 M HCl has been investigated by electrochemical impedance, potentiodynamic polarization measurements and quantum chemical methods.

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20

Zhao, Can, Xiao-Zong Li, Hong-Lan Kang та Yi-Hang Wen. "Crystal structure of poly[{μ3-(E)-3-[3-(carboxylatomethoxy)phenyl]acrylato-κ3O,O′:O′′:O′′′}[μ2-3-(pyridin-4-yl)-1H-pyrazole-κ2N:N′]cobalt(II)]". Acta Crystallographica Section E Crystallographic Communications 72, № 10 (2016): 1425–28. http://dx.doi.org/10.1107/s205698901601402x.

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The title compound, [Co(C11H8O5)(C8H7N3)]n, which is based on (E)-3-[3-(carboxymethoxy)phenyl]acrylic acid (H2L) and 3-(pyridin-4-yl)pyrazole (pp) ligands, has been synthesized under solvothermal conditions. The dihedral angle between pyrazole and pyridine rings in the pp ligands is 23.1 (2)°. In the crystal, helical chains formed by pp andLligands connected to the CoIIatom propagate parallel to thecaxis. CoIIatoms of adjacent chains are bridged by the acrylic acid groups ofLligands into corrugated polymeric sheets in theacplane.

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21

Huang, Feng, Bin Jin, and Jian-Feng Zhang. "3-[3-(2-Pyridyl)-1H-pyrazol-1-yl]propanamide." Acta Crystallographica Section E Structure Reports Online 65, no. 6 (2009): o1411. http://dx.doi.org/10.1107/s1600536809019060.

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In the title compound, C11H12N4O, the pyrazole and pyridine rings are nearly coplanar [dihedral angle = 1.87 (5)°]. Adjacent molecules are linked by N—H...N and N—H...O hydrogen bonds into a linear chain running along thecaxis.

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22

Alsayari, Abdulrhman, Yahya I. Asiri, Abdullatif Bin Muhsinah, and Mohd Zaheen Hassan. "Anticolon Cancer Properties of Pyrazole Derivatives Acting through Xanthine Oxidase Inhibition." Journal of Oncology 2021 (July 5, 2021): 1–5. http://dx.doi.org/10.1155/2021/5691982.

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Background. Pyrazoles are an interesting class of compounds showing potent anticancer activities. Our previous studies have demonstrated the potent anticancer activity of pyrazole analogues. Therefore, we focused on developing anticancer agents through structure optimization of the pyrazolyl lead molecule. Methods. The pyrazole derivatives were prepared by the appropriate synthetic protocols. The antiproliferative activities were evaluated using a sulforhodamine B assay against three cancer cell lines. In vitro and in silico molecular docking studies employing xanthine oxidase were used to exp

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23

Lynch, Brian Maurice, Misbahul Ain Khan, Huk Chia Teo, and Francisco Pedrotti. "Pyrazolo[3,4-b]pyridines: Syntheses, reactions, and nuclear magnetic resonance spectra." Canadian Journal of Chemistry 66, no. 3 (1988): 420–28. http://dx.doi.org/10.1139/v88-074.

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Efficient syntheses of approximately 70 simple substituted representatives of pyrazolo[3,4-b]pyridine 1 are reported from the following: (a) suitably substituted pyridines onto which a pyrazole ring is annelated, and (b) appropriately substituted pyrazoles onto which a pyridine ring is annelated. Selected examples of electrophilic, nucleophilic, and homolytic substitution reactions and group transformations are described, providing regiosynthetic paths to useful intermediate species. Some systematic aspects of substituent chemical shift influences in the 1H and 13C nuclear magnetic resonance s

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24

Dotsenko, Victor V., Vladimir A. Dushenko, Nikolai A. Aksenov, Inna V. Aksenova, and Evgeniy E. Netreba. "The First Synthesis of [1,2]oxaphosphinino[6,5-c]pyrazoles by Thiophosphorylation of 6-Aminopyrano[2,3-c]pyrazole-5-Carbonitriles." Proceedings 9, no. 1 (2018): 26. http://dx.doi.org/10.3390/ecsoc-22-05680.

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The reaction of 6-amino-3-methyl-2,4-dihydropyrano[2,3-c]pyrazole-5-carbonitriles with phosphorus sulfide in boiling pyridine leads to the formation of the unexpected [1,2]oxaphosphinino[6,5-c]pyrazoles. The structure of the products was confirmed with 2D Nuclear Magnetic Resonance (NMR) spectroscopy and X-ray analysis.

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25

Sazanovich, Igor V., Mohammed A. H. Alamiry, Anthony J. H. M. Meijer, et al. "Photoinduced charge separation in a PtII acetylide donor–acceptor triad based on 2-(1-pyrazole)-pyridine modified with naphthalene mono-imide electron acceptor." Pure and Applied Chemistry 85, no. 7 (2013): 1331–48. http://dx.doi.org/10.1351/pac-con-13-04-02.

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A class of molecular electron transfer cascades—those based on PtII complexes of 2-(1-pyrazole)-pyridine (pzpy) ligands—are reported. The synthesis of a new electron-acceptor imide-modified pzpy ligands is reported, and their application to transition-metal chemistry demonstrated by the synthesis of the PtII chloride and acetylide complexes. These donor–acceptor assemblies are promising models for investigation of photoinduced charge separation. Accordingly, picosecond time-resolved infrared (TRIR) and femtosecond transient absorption (TA) studies have been undertaken to elucidate the nature a

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26

Král, Vladimír, Viktor Vladimirovich Semenov, Mikhail Ivanovich Kanishchev, Zdeněk Arnold, Svyatoslav Arkadievich Shevelev, and Albert Aleksandrovich Fainzilberg. "A general method of preparation of N-diformylmethylazoles and cycloimonium diformyl methylides." Collection of Czechoslovak Chemical Communications 53, no. 7 (1988): 1519–28. http://dx.doi.org/10.1135/cccc19881519.

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Formylation of easily accessible heteroarylacetic acids (R-CH2COOH, R = imidazole, pyrazole, tetrazole, pyridine) afforded in high yields the corresponding trimethinium salts R-C(=CH-N(CH3)2)CH=N(CH3)2)n+ nX- which on alkaline hydrolysis were converted into N-diformylmethylazoles R-C(CHO)=CH-OH. Their quaternization gave cycloimonium diformyl methylides.

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27

De, Avik, Sukhen Bala, Sayan Saha, et al. "Lanthanide clusters of phenanthroline containing a pyridine–pyrazole based ligand: magnetism and cell imaging." Dalton Transactions 50, no. 10 (2021): 3593–609. http://dx.doi.org/10.1039/d0dt04122j.

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In this contribution, we report the synthesis, characterization and luminescence–magnetic properties of Ln-clusters (Ln = Gd<sup>3+</sup>, Eu<sup>3+</sup> and Tb<sup>3+</sup>) using a new pyridine–pyrazole functionalized ligand fitted with a chromophoric phenanthroline backbone. We have applied the luminescence property of clusters for cancer cell imaging.

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28

Dawood, Kamal M., Eman A. Ragab, and Sanaa N. Mohamed. "Synthesis of Some New Indolizine and Pyrrolo[1,2-a]quinoline Derivatives via Nitrogen Ylides." Zeitschrift für Naturforschung B 64, no. 4 (2009): 434–38. http://dx.doi.org/10.1515/znb-2009-0413.

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Pyridine and quinoline react with 3-bromoacetyl-1,5-diphenyl-1H-pyrazole-4-carbonitrile (2) in dry benzene to give the corresponding pyridinium and quinolinium salts 3 and 9. The latter salts undergo [3+2] 1,3-dipolar cycloaddition with some acetylene and ethylene derivatives to give the corresponding indolizine and pyrrolo[1,2-a]quinoline derivatives

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29

Flefel, Eman M., Walaa I. El-Sofany, Mahmoud El-Shahat, Arshi Naqvi, and Eman Assirey. "Synthesis, Molecular Docking and in Vitro Screening of Some Newly Synthesized Triazolopyridine, Pyridotriazine and Pyridine–Pyrazole Hybrid Derivatives." Molecules 23, no. 10 (2018): 2548. http://dx.doi.org/10.3390/molecules23102548.

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A series of novel pyridine and fused pyridine derivatives have been prepared starting from 6-(3,4-dimethylphenyl)-2-hydrazinyl-4-(thiophen-2-yl)-pyridine-3-carbonitrile 1 which on treatment with appropriate formic acid, acetic acid/ acetic anhydride, benzoyl chloride and/or carbon disulfide afforded the corresponding triazolopyridine derivatives 2–5. Also, treatment of hydrazide 1 with diethyloxalate, chloroacetyl chloride, chloroacetic acid and/or 1,2-dichloroethane yielded the corresponding pyridotriazine derivatives 7–10. Further transformation of compound 1 with a different active methylen

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30

Bouklah, M., A. Attayibat, B. Hammouti, A. Ramdani, S. Radi, and M. Benkaddour. "Pyridine–pyrazole compound as inhibitor for steel in 1M HCl." Applied Surface Science 240, no. 1-4 (2005): 341–48. http://dx.doi.org/10.1016/j.apsusc.2004.07.001.

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31

Abu Thaher, Bassam, Pierre Koch, Dieter Schollmeyer, and Stefan Laufer. "4-[5-Amino-4-(4-fluorophenyl)-3-(pyridin-4-yl)-1H-pyrazol-1-yl]benzonitrile." Acta Crystallographica Section E Structure Reports Online 68, no. 4 (2012): o935. http://dx.doi.org/10.1107/s160053681200877x.

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In the crystal structure of the title compound, C21H14FN5, the pyrazole ring forms dihedral angles of 38.0 (1), 40.0 (1) and 28.5 (1)° with the directly attached 4-fluorophenyl, pyridine and benzonitrile rings, respectively. The crystal packing is characterized by N—H...N hydrogen bonds, which result in a two-dimensional network parallel to theac-plane.

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32

Huang, Ping-Hsin, Yuh-Sheng Wen, and Jiun-Yi Shen. "3-Iodo-1H-pyrazolo[3,4-b]pyridine." Acta Crystallographica Section E Structure Reports Online 70, no. 6 (2014): o650. http://dx.doi.org/10.1107/s1600536814010009.

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The title compound, C6H4IN3, is essentially planar, with a dihedral angle of 0.82 (3)° between the planes of the pyridine and pyrazole rings. In the crystal, pairs of molecules are connected into inversion dimers through N—H...N hydrogen bonds. C—I...N halogen bonds link the dimers into zigzag chains parallel to theb-axis direction. The packing also features π–π stacking interactions along (110) with interplanar distances of 3.292 (1) and 3.343 (1) Å, and centroid–centroid distances of 3.308 (1) and 3.430 (1) Å.

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33

Mohareb, Rafat M., Sherif M. Sherif, Adiba Habashi, Nadia I. Abdel-Sayed, and Samia S. Osman. "Reaction of Carbon Disulfide with Active Methylenes: Novel Synthesis of Thiophene, Thieno[2,3-b]thiophene, Thieno[3,2-c]pyrazole and Thieno[3,2-b]pyridine Derivatives." Collection of Czechoslovak Chemical Communications 60, no. 9 (1995): 1578–86. http://dx.doi.org/10.1135/cccc19951578.

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The active methylene compounds - derivatives of malonic or 4-oxobutanoic acid - reacted with carbon disulfide in dimethyl formamide containing potassium hydroxide to yield the non-isolable dipotassium disulfide intermediates. The latter were cyclized by α-haloketones to give thiophene, thieno[2,3-b]thiophene, thieno[3,2-c]pyrazole and thieno[3,2-b]pyridine derivatives. The reactivity of the products toward various reagents was studied.

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34

Tan, Zheng-De, Feng-Jiao Tan, Bo Tan, and Cheng-Ming Zhang. "4-(1H-Pyrazol-3-yl)pyridine–terephthalic acid–water (2/1/2)." Acta Crystallographica Section E Structure Reports Online 68, no. 6 (2012): o1942. http://dx.doi.org/10.1107/s1600536812021599.

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In the title compound, 2C8H7N3·C8H6O4·2H2O, the pyridine and pyrazole rings are approximately coplanar, the dihedral angle between them being 4.69 (9)°. The asymmetric unit consists of half of the terephthalic acid (an inversion centre generates the other half of the molecule), one 4-(1H-pyrazol-3-yl)pyridine (4pp) molecule and one water molecule. In the crystal, two 4pp and one terephthalic acid molecules form a linear three-molecule unit as a result of O—H...N hydrogen bonds. These units are further assembled into a three-dimensional network by two types of hydrogen bonds, viz. O—H...O and N

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35

Shiga, Takuya, Graham N. Newton, and Hiroki Oshio. "Pre-programmed self-assembly of polynuclear clusters." Dalton Transactions 47, no. 22 (2018): 7384–94. http://dx.doi.org/10.1039/c8dt00822a.

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This perspective reviews our recent efforts towards the self-assembly of polynuclear clusters with ditopic and tritopic multidentate ligands HL<sup>1</sup> (2-phenyl-4,5-bis{6-(3,5-dimethylpyrazol-1-yl)pyrid-2-yl}-1H-imidazole) and H<sub>2</sub>L<sup>2</sup> (2,6-bis-[5-(2-pyridinyl)-1H-pyrazole-3-yl]pyridine), both of which are planar and rigid molecules.

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36

Nasibullin, R. S., D. I. Kosareva, M. A. Serebrenik, and L. V. Spirikhin. "Study on the structure of phosphatidylcholine-pyrazole and phosphatidylcholine-pyridine complexes." Biopolymers and Cell 18, no. 1 (2002): 76–80. http://dx.doi.org/10.7124/bc.0005eb.

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37

Hormaza, Angelina, Dieter Schollmeyer, and Herbert Meier. "Synthese und Kristallstrukturanalyse eines 2,4-Diaryl-2,3-dihydro-1H-1,5-benzodiazepins / Synthesis and Crystal Structure Analysis of a 2,4-Diaryl-2,3-dihydro-1H-1,5-benzodiazepine." Zeitschrift für Naturforschung B 59, no. 1 (2004): 73–76. http://dx.doi.org/10.1515/znb-2004-0111.

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AbstractThe enone unit of chalcones is a synthetically valuable substructure for the formation of heterocycles. Whereas propoxy groups as solubilizing side chains on the phenyl groups do not much affect the generation of pyrazole and pyridine rings, they reduce significantly the yield of the diazepine ring system 4. We attribute this effect to the large twist angles between the ring planes, which are demonstrated by a crystal structure analysis.

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38

Deeb, Ali, Medhat El-Mobayed, Abdel Naby Essawy, Adel Abd El-Hamid, and Atef Mohamid Abd El-Hamid. "Heterocyclic synthesis from 3-amino-4-cyanopyrazole." Collection of Czechoslovak Chemical Communications 55, no. 3 (1990): 728–33. http://dx.doi.org/10.1135/cccc19900728.

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3-Amino-4-cyanopyrazole I reacts with hydroxylamine and with hydrazine to yield 1H,6H-3-aminopyrazolo[3,4-c]pyrazole (III and IV). Diazotized IV couples with 2-naphthol to give the arylazo derivative VI which cyclizes to 9H-naphthol[2,1-e]pyrazolo[3',4':3,4]pyrazolo[5,1-c]-[1,2,4]triazine VII by means of acetic acid. The pyrazol-5-ylthiourea obtained from I and phenyl isothiocyanate undergoes base-catalyzed cyclization to give pyrazolo[3,4-d]pyrimidinethione derivative IX. Compound I reacts with cyclohexane in the presence of zinc chloride to give the tetrahydropyrazolo[3,4-b]quinoline derivat

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39

Phillip, IG, and PJ Steel. "X-Ray Crystal Structures of 2,2'-Bis(pyrazol-1-yl)-4,4'-bipyridine and a Tetramethyl Derivative; New Bis-bidentate Binucleating Ligands." Australian Journal of Chemistry 48, no. 9 (1995): 1617. http://dx.doi.org/10.1071/ch9951617.

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X-Ray crystal structures of 2,2°-bis(pyrazol-1-yl)-4,4°-bipyridine (3) and 2,2°-bis(3,5-dimethyl-pyrazol-1-yl)-4,4°-bipyridine (4) have been determined at 130 K. Crystals of (3) are triclinic, Pī , a 8.061(1), b 9.024(1), c 10.680(1)Ǻ, α 102.032(8), β 107.931(6), γ 107.355(7)°, Z = 2; the structure was refined to a conventional R(I > 2σ(I)) = 0.0273. Crystals of (4) are orthorhombic, P 212121, a 7.077(2), b 13.906(4), c 16.697(5) Ǻ, Z = 4; the structure was refined to a conventional R(I > 2σ(I)) = 0.0386. In both molecules there is significant (33�1°) twisting about the central pyridine-

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40

Abd El-Sattar, Nour E. A., Eman H. K. Badawy, and M. S. A. Abdel-Mottaleb. "Synthesis of Some Pyrimidine, Pyrazole, and Pyridine Derivatives and Their Reactivity Descriptors." Journal of Chemistry 2018 (November 13, 2018): 1–11. http://dx.doi.org/10.1155/2018/8795061.

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A series of novel pyrimidine (2, 3), pyrazole (4, 5), and pyridine (6) derivatives were synthesized using a chalcone-bearing thiophene nucleus (1). The target compounds were synthesized by reaction of compound (1) with urea, thiourea, malononitrile, hydrazine hydrate, and 2,4-dinitrophenyl hydrazine, respectively. Molecular electronic structures have been modeled within density functional theory framework (DFT). Reactivity indices and electrostatic surface potential maps (ESP maps) allow us to establish trends that enable making predictions about chemical characteristics of the newly synthesiz

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41

Olguín, Juan, and Sally Brooker. "Spin crossover active iron(II) complexes of selected pyrazole-pyridine/pyrazine ligands." Coordination Chemistry Reviews 255, no. 1-2 (2011): 203–40. http://dx.doi.org/10.1016/j.ccr.2010.08.002.

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42

Palmer, Michael H. "Nuclear Quadrupole Coupling Constant assignments for a series of azoles and azines by Hartree-Fock SCF-Cluster and Lattice Calculations." Zeitschrift für Naturforschung A 51, no. 5-6 (1996): 451–59. http://dx.doi.org/10.1515/zna-1996-5-621.

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Abstract We present ab initio Hartree-Fock lattice calculations on a series of heterocyclic and other compounds. Some of these have previously been studied by cluster calculations with the same DZ basis sets at the SCF level. The electric field gradients at the nitrogen centres, are related to NQR experimental determinations of nuclear quadrupole coupling constants. The compounds studied include imidazole and pyrazole, 4-nitroimidazole, 4-nitropyrazole, pyrazine, and tetramethylpyrazine, pyridinium chloride, and N-methylpyridinium iodide, and pyridine-N-oxide.

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43

Watson, AA, DA House, and PJ Steel. "Chiral Heterocyclic Ligands. VIII. Syntheses and Complexes of New Chelating Ligands Derived From Camphor." Australian Journal of Chemistry 48, no. 9 (1995): 1549. http://dx.doi.org/10.1071/ch9951549.

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The syntheses of 23 new chelating ligands are described. Most of these ligands are derived from the chiral pyrazole (1) which has been linked to a variety of heterocycles , namely pyridine, pyrimidine, pyridazine, isoxazole , benzimidazole, thiophen and furan. In certain cases the parent achiral analogues have also been prepared. Preliminary studies of the coordination chemistry of these ligands with selected transition metals have been carried out. The X-ray crystal structures of palladium complexes of isoxazole- and thiophen-containing ligands have also been determined.

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44

Hrynyshyn, Yevhenii, Hanna Musiichuk, Olena Komarovska-Porokhnyavets, et al. "Synthesis and Antimicrobial Activity of 4-Arylthio- and 4 Alkylthiofunctionalized Pyrazolo[1,5-a]pyrazines." Ukrainian Chemistry Journal 85, no. 1 (2019): 58–66. http://dx.doi.org/10.33609/0041-6045.85.1.2019.58-66.

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The reaction of pyrazolo[1,5-a]pyrazine-4(5H)ones with phosphorus tribromoxide in boiling benzene yielded 4-bromopyrazolo[1,5-a]pyrazines, and the thionation with phosphorus pentasulfide in pyridine at 90 °C led to pyrazolo[1,5-a]pyrazine-4(5H)thiones. The synthesized bromine derivatives are electrophilic, and thiones are nucleophilic substrates. Their subsequent structural modification in the first case was carried out by interaction with thiophenols, and in the second case was conducted with functional halogenoalkanes. It was shown that bromides react with substituted thiophenols in dimethyl

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45

Kheder, Nabila A., Yahia N. Mabkhot, and Ahmad M. Farag. "Facile and Convenient Synthesis of Pyrazole, Pyridine, Pyridazine, Pyrazolo[3,4-b]pyridine, and Pyrazolo[5,1-c][1,2,4]triazine Derivatives." Synthetic Communications 38, no. 18 (2008): 3170–82. http://dx.doi.org/10.1080/00397910802109257.

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46

Terashima, Shotaro, Graham N. Newton, Takuya Shiga, and Hiroki Oshio. "Planar trinuclear complexes with linear arrays of metal ions." Inorganic Chemistry Frontiers 2, no. 2 (2015): 125–28. http://dx.doi.org/10.1039/c4qi00172a.

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Using a pyridine–pyrazolate ligand H<sub>2</sub>L (5,5′-pyridyl-3,3′-bi-1H-pyrazole) with two types of bidentate sites allowed the isolation of two trinuclear complexes, [Cu<sub>3</sub>(L)<sub>2</sub>](BF<sub>4</sub>)<sub>2</sub> (1) and [Ni<sub>3</sub>(L)<sub>2</sub>(MeOH)<sub>4</sub>](BF<sub>4</sub>)<sub>2</sub> (2). Both complexes have linear trinuclear structures composed of two L<sup>2−</sup> ligands and three metal ions in a planar arrangement.

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47

Yang, Luan-Fang, Hong-Bo Hou, and Yi-Ming Liu. "4-(4,5-Dihydro-1H-benzo[g]indazol-3-yl)pyridinium chloride dihydrate." Acta Crystallographica Section E Structure Reports Online 68, no. 8 (2012): o2366. http://dx.doi.org/10.1107/s160053681203019x.

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In the cation of the title compound, C16H14N3+·Cl−·2H2O, the cyclohexa-1,3-diene ring displays a screw-boat conformation and the pyridine ring is slightly twisted with respect to the pyrazole ring with a dihedral angle of 4.56 (12)°. In the crystal, ions and water molecules are linked into a three-dimensional network by classical N—H...O, N—H...Cl, O—H...Cl and O—H...O hydrogen bonds and by π–π stacking interactions, with centroid–centroid distances of 3.7580 (14) and 3.7794 (14) Å.

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48

Halim, Nazar M., Vladislav Abramov, Ingo Pantenburg, and Gerd Meyer. "Two New Chromium(III) Complexes with the Pincer-type Pyridine-2,6-dicarboxylate Ligand." Zeitschrift für Naturforschung B 66, no. 7 (2011): 685–88. http://dx.doi.org/10.1515/znb-2011-0706.

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The synthesis and crystal structures of two new salts of chromium(III) with pyridine-2,6-dicarboxylic acid H2Pda (and 2,2’-bipyridyl, Bpy, as a co-ligand) are reported, (HPyz)[Cr(Pda)2](H2Pda)-(H2O)5 (1) and [Cr(Pda)(Bpy)(H2O)][Cr(Pda)2](H2O)2 (2). Both crystal structures contain the octahedral [Cr(Pda)2]− anion with the pincer-type O,N,O-Pda2− ligand. In 1, the pyrazole additive does not act as a ligand, rather it is included as a mono-protonated cation. In 2, both Pda2−, the neutral 2,2’-bipyridyl and water are coordinating Cr3+ in the cation [Cr(Pda)(Bpy)(H2O)]+.

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49

Kim, Daeyoung, та Sung Kwon Kang. "Crystal structure of aqua(1H-pyrazole-κN2)(pyridine-2,6-dicarboxylato-κ3O2,N,O6)copper(II) dihydrate". Acta Crystallographica Section E Crystallographic Communications 73, № 12 (2017): 1875–77. http://dx.doi.org/10.1107/s2056989017016231.

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In the title compound, [Cu(C7H3NO4)(C3H4N2)(H2O)]·2H2O, the CuIIatom is coordinated by three O atoms and two N atoms, provided by a tridentate pyridine-2,6-dicarboxylate (pdc), one pyrazole and one water ligand, forming a slightly distorted square-pyramidal geometry [range of O—Cu—O and O—Cu—N bond angles = 79.55 (8)–166.22 (10)°]. The water molecule is positioned at the apical position. In the crystal, the complex molecule and the two crystallographically independent non-coordinating water molecules are linked into a supramolecular layer structure parallel to theabplaneviaO—H...O and N—H...O

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50

Desai, Nisheeth C., Darshita V. Vaja, Krunalsinh A. Jadeja, Surbhi B. Joshi, and Vijay M. Khedkar. "Synthesis, Biological Evaluation and Molecular Docking Study of Pyrazole, Pyrazoline Clubbed Pyridine as Potential Antimicrobial Agents." Anti-Infective Agents 18, no. 3 (2020): 306–14. http://dx.doi.org/10.2174/2211352517666190627144315.

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Introduction: In continuation of our efforts to find new antimicrobials, herein we report the synthesis of various pyrazole, pyrazoline, and pyridine based novel bioactive heterocycles (3a-t). Methods: Newly synthesized compounds were analysed for their antimicrobial activity. Compounds 3c, 3h, 3i, 3k, 3n, and 3q showed significant antimicrobial activity. Results: Molecular docking study for the most active analogues against DNA gyrase subunit b (PDB ID: 1KZN) corroborated well with the observed antimicrobial potency exhibiting significant binding affinity. Conclusion: Interpretation of the ch

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