The structural resemblance between the fused imidazopyridine heterocyclic ring system and purines has prompted biological investigations to assess their potential therapeutic significance. They are ...known to play a crucial role in numerous disease conditions. The discovery of their first bioactivity as GABA
receptor positive allosteric modulators divulged their medicinal potential. Proton pump inhibitors, aromatase inhibitors, and NSAIDs were also found in this chemical group. Imidazopyridines have the ability to influence many cellular pathways necessary for the proper functioning of cancerous cells, pathogens, components of the immune system, enzymes involved in carbohydrate metabolism, etc. The collective results of biochemical and biophysical properties foregrounded their medicinal significance in central nervous system, digestive system, cancer, inflammation, etc. In recent years, new preparative methods for the synthesis of imidazopyridines using various catalysts have been described. The present manuscript to the best of our knowledge is the complete compilation on the synthesis and medicinal aspects of imidazo4,5-
pyridines and imidazo4,5-
pyridines reported from the year 2000 to date, including structure-activity relationships.
Various methods, such as XRF, XRD, SEM, N.sub.2 adsorption/desorption, NH.sub.3-TPD, and IR spectroscopy of adsorbed pyridine, were used to characterize SAPO-11 samples crystallized from ...Al-isopropoxide as an aluminum source and from SiO.sub.2 with various dispersions (4, 22, and 200 nm) as a silicon source. Decreasing the size of SiO.sub.2 particles was shown to enhance the total concentration of acid sites and to affect the morphology and increase the dispersion of the primary crystals. These SAPO-11 samples were then tested in the oligomerization of alpha-methylstyrene into its valuable dimers. The SAPO sample synthesized using a SiO.sub.2 sol with an average particle size of 4 nm exhibited a higher concentration of strong acid sites and higher accessibility of those sites than the other tested samples. These advantages allowed this SAPO sample to achieve the highest monomer conversion and the highest alpha-methylstyrene dimer selectivity.
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Pyridine-based compounds have been playing a crucial role as agrochemicals or pesticides including fungicides, insecticides/acaricides and herbicides, etc. Since most of the ...agrochemicals listed in the Pesticide Manual were discovered through screening programs that relied on trial-and-error testing and new agrochemical discovery is not benefiting as much from the in silico new chemical compound identification/discovery techniques used in pharmaceutical research, it has become more important to find new methods to enhance the efficiency of discovering novel lead compounds in the agrochemical field to shorten the time of research phases in order to meet changing market requirements. In this review, we selected 18 representative known agrochemicals containing a pyridine moiety and extrapolate their discovery from the perspective of Intermediate Derivatization Methods in the hope that this approach will have greater appeal to researchers engaged in the discovery of agrochemicals and/or pharmaceuticals.
A new route for the synthesis of quinazolin-2,4(1H,3H)-diones and thieno 2,3-dpyrimidine-2,4(1H,3H)-diones substituted by pyridyl/quinolinyl moiety in position 3 has been developed. The proposed ...method concluded in an annulation of substituted anthranilic esters or 2-aminothiophene-3-carboxylates with 1,1-dimethyl-3-(pyridin-2-yl) ureas. The process consists of the formation of N-aryl-N′-pyridyl ureas followed by their cyclocondensation into the corresponding fused heterocycles. The reaction does not require the use of metal catalysts and proceeds with moderate to good yields (up to 89%). The scope of the method is more than 30 examples, including compounds with both electron-withdrawing and electron-donating groups, as well as diverse functionalities. At the same time, strong electron-acceptor substituents in the pyridine ring of the starting ureas reduce the product yield or even prevent the cyclocondensation step. The reaction can be easily scaled to gram quantities.
Terpyridine-Based Materials Schubert, Ulrich S; Winter, Andreas; Newkome, George R
2011, 2012-09-25, 2011-08-24
eBook
In recent years, the utilization of terpyridines both in macromolecular structure assembly and device chemistry has exploded, enabling, for example, supramolecular polymer architectures with ...switchable chemical and physical properties as well as novel functional materials for optoelectronic applications such as light-emitting diodes and solar cells. Further applications include the usage of terpyridines and their metal complexes as catalysts for asymmetric organic reactions and, in a biological context, as anti-tumor agents or biolabels. This book covers terpyridine-based materials topics ranging from syntheses, chemistry, and multinuclear metal complexes, right up to functionalized polymers, 3D-architectures, and surfaces. Aimed at materials scientists, (in)organic chemists, polymer chemists, complex chemists, physical chemists, biochemists, and libraries.
Keywords: brightness; chirality; chromium; CPL; dissymmetry factor A series of highly emissive inert and chiral Cr.sup.III complexes displaying dual circularly polarized luminescence (CPL) within the ...NIR region have been prepared and characterized. The helical Cr(dqpR).sub.2.sup.3+ (dqp=2,6-di(quinolin-8-yl)pyridine; R=OCH.sub.3, Br or Ca CH) complexes were synthesized as racemic mixtures and resolved into their respective PP and MM enantiomers by chiral stationary phase HPLC. The corresponding enantiomers show large g.sub.luma0.2 and high quantum yield of up to 17%, which afford important CPL brightness of up to 170 m.sup.-1cm.sup.-1, a key point for applications as chiral luminescent probes. Moreover, the long-lived CP-NIR emission provided by these chromophores (ms range) in aqueous solution opens the way toward the quantification of chiral targets in biological systems with time-gated detection. Thus, such chiral chromophores based on earth abundant and inert 3d metals open new perspectives in the field of CPL and represent an alternative to precious 4d, 5d and to labile 4f metal-based complexes. Article Note: These authors contributed equally to this work. Supporting information: Additional Supporting Information may be found in the online version of this article As a service to our authors and readers, this journal provides supporting information supplied by the authors. Such materials are peer reviewed and may be re-organized for online delivery, but are not copy-edited or typeset. Technical support issues arising from supporting information (other than missing files) should be addressed to the authors. CAPTION(S): Supplementary Byline: Juan-Ramon Jimenez, Juan-Ramon Jimenez, Juan-Ramon Jimenez, Stephane Grass, Jerome Lacour, Celine Besnard, Juan M. Cuerva, Araceli G. Campana, Claude Piguet
High-Temperature Spin Crossover in Ironpyridine Lavrenova, Ludmila G; Shakirova, Olga G; Korotaev, Evgeniy V ...
Molecules (Basel, Switzerland),
08/2022, Letnik:
27, Številka:
16
Journal Article
Recenzirano
Novel iron(II) coordination compounds containing a ligand 2,6-bis(1H-imidazol-2-yl)pyridine (L), having such a composition as FeLsub.2SOsub.4·0.5Hsub.2O, FeLsub.2Brsub.2·Hsub.2O, ...FeLsub.2(ReOsub.4)sub.2, FeLsub.2Bsub.10Hsub.10∙Hsub.2O, FeLsub.2Bsub.12Hsub.12∙1.5Hsub.2O had been synthesized and studied using UV-Vis (diffuse reflectance), infrared, extended X-ray absorption fine structure (EXAFS), and Mössbauer spectroscopy methods, as well as X-ray diffraction and static magnetic susceptibility methods. The analysis of the μsub.eff(T) dependence in the temperature range of 80-600 K have shown that all the obtained complexes exhibit a high-temperature spin crossover sup.1Asub.1 ↔ sup.5Tsub.2.
Two variants of the Graebe-Ullmann reaction were used to obtain 8-methyl-5H-pyrido4,3-bindole (8-methyl-γ-carboline) and the conditions for this reaction were optimized. The feasibility of using this ...method was studied for the synthesis of a series of isomeric aromatic aza-γ-carbolines from the corresponding 1-(pyridyl)-1H-1,2,3-triazolo4,5-cpyridines under thermal and microwave irradiation conditions.
A series of uni- and biquaternized derivatives of alpha-pyridoin and 2, 2'-pyridyl were synthesized. Their antimicrobial activity (AMA) was studied with respect to Gram-negative (E. coli) and ...Gram-positive (S. aureus) bacterial strains. It was established that the AMA depended on the nature of the radical and the presence of an oxygen between the pyridyl rings. The maximum activity was observed for 2, 3-bis-(Ar-dodecylpyridirtium-2'-yl)quinoxaline dibromide. Keywords: quaternization, antimicrobial activity, alpha-pyridoin, 2,2'-pyridyl, quinoxaline.
The self-condensation of cyclopentanone has been studied over calcined and uncalcined TiO.sub.2-ZrO.sub.2. The catalyst properties were examined by XRD, FTIR, SEM, N.sub.2 adsorption-desorption, and ...pyridine FTIR. Compared with calcined TiO.sub.2-ZrO.sub.2, uncalcined TiO.sub.2-ZrO.sub.2 exhibited superior catalytic performance (94% conversion of cyclopentanone and 86% yield of dimer). This might be because uncalcined TiO.sub.2-ZrO.sub.2 has both Lewis and Brønsted acids, while calcined TiO.sub.2-ZrO.sub.2 only contains Lewis acids. Kinetics analysis indicated that C-C coupling was the rate-limiting step on the two catalysts. For uncalcined TiO.sub.2-ZrO.sub.2, the C-C coupling occurred between the two species on the catalyst surface. Through the H bond, the cyclopentanone was firmly adsorbed on the catalyst surface by Brønsted acid sites, then the enol intermediate could attack another cyclopentanone polarized by adjacent Lewis acid sites. As a consequence, the coexistence of Brønsted and Lewis acids in catalysts exhibited enhanced activity in cyclopentanone self-condensation. Graphical
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