CuO–CuAl2O4 and d-glucose catalyzed synthesis of a family of excited state intramolecular proton transfer imidazo[1,2-a]pyridine analogues and their optical properties

Balijapalli, Umamahesh; Iyer, Sathiyanarayanan Kulathu

doi:10.1016/j.dyepig.2015.05.014

Cited by 27 publications

(20 citation statements)

References 43 publications

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“…Prior to the synthesis of the desired complexes, we focused our attention on the (N,O)-donor compounds. To date only a few crystal structures of analogous 2-(2 0 -hydroxyphenyl)imidazo[1,2-a]pyridines can be found in the literature (Stasyuk, Bultinck et al, 2016;Stasyuk, Cywiń ski & Gryko, 2016;Mutai et al, 2008Mutai et al, , 2016Mutai et al, , 2014An et al, 2016;Salunke et al, 2012;Balijapalli & Iyer, 2015;Wu et al, 2017). Among them, two compounds crystallized by some of us (Stasyuk, Bultinck et al,…”

Section: Resultsmentioning

confidence: 99%

Structural, energetic and spectroscopic studies of new luminescent complexes based on 2-(2′-hydroxyphenyl)imidazo[1,2-a]pyridines and 1,2-phenylenediboronic acid

Kutniewska

Jarzembska

Kamiński

et al. 2018

Acta Crystallogr B Struct Sci Cryst Eng Mater

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Three new blue-luminescent complexes of selected imidazo[1,2-a]pyridine derivatives and 1,2-phenylenediboronic acid have been synthesized and structurally characterized using single-crystal X-ray diffraction. Additionally, the crystal structures of two of the (N,O)-donor compounds have been evaluated for the first time. The crystal packing and molecular motifs observed in the studied crystals have been thoroughly analysed, including computational studies, and are also discussed within the context of analogous systems reported in the literature. It appears that the new compounds form different crystal networks with regard to the asymmetric unit content and packing, although some similarities can be found. In all cases a typical centrosymmetric dimer bound via boronic acid groups is formed, characterized by an interaction energy of about À80 kJ mol À1 , while the 2-(2 0 -hydroxyphenyl)imidazo[1,2-a]pyridine complex and its methoxy derivative form solvate structures, somewhat resembling the previously studied 8-oxyquinolinate analogues. As far as the spectroscopic properties are concerned, the lowest energy excitation observed in the studied complexes is based on the highest occupied molecular orbital-lowest unoccupied molecular orbital transition, and both these molecular orbitals are centred predominantly on the (N,O)-donor species according to the results of time-dependent density functional theory. Thus, the charge transfer observed for the 8-oxyquinolinate equivalents does not occur in these cases. Consequently, the spectroscopic behaviour of the series is very much comparable with that of the parent imidazo[1,2-a]pyridine derivatives, if the excited-state intramolecular proton-transfer process does not take place, as shown by the absorption and emission spectra collected in toluene and acetone solutions. Complexation causes a reduction in the Stokes shift compared with the respective (N,O)-donor molecules. research papers Acta Cryst. (2018). B74, 725-737 Sylwia E. Kutniewska et al. Complexes of C 14 H 12 N 2 O 2 and C 13 H 9 BrN 2 O 727 research papers 728 Sylwia E. Kutniewska et al. Complexes of C 14 H 12 N 2 O 2 and C 13 H 9 BrN 2 O Acta Cryst. (2018). B74, 725-737 Figure 2 Crystal packing of the bromine derivative, c. (a) A view along the [100] direction and (b) a view along the [010] direction. research papers Acta Cryst. (2018). B74, 725-737 Sylwia E. Kutniewska et al. Complexes of C 14 H 12 N 2 O 2 and C 13 H 9 BrN 2 O 735 research papers Acta Cryst. (2018). B74, 725-737 Sylwia E. Kutniewska et al. Complexes of C 14 H 12 N 2 O 2 and C 13 H 9 BrN 2 O 737

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Section: Resultsmentioning

confidence: 99%

Structural, energetic and spectroscopic studies of new luminescent complexes based on 2-(2′-hydroxyphenyl)imidazo[1,2-a]pyridines and 1,2-phenylenediboronic acid

Kutniewska

Jarzembska

Kamiński

et al. 2018

Acta Crystallogr B Struct Sci Cryst Eng Mater

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“…The protocol also provided a concise route for the synthesis of the antiulcer drug zolimidine in 95% yield. A three-component coupling reaction (3-CCR) for the synthesis of N-fused pyridines was reported by Balijapalli and Iyer [40]. The reaction was catalyzed by CuO/CuAl 2 O 4 and ᴅ-glucose.…”

Section: Reviewmentioning

confidence: 99%

“…In comparison with other TMs copper-metal-based catalysts are cheap, nontoxic, abundant and environmentally benign [40]. Chemistry of Cu is extremely rich as it can exist in variable oxidation states (Cu(0), Cu(I), Cu(II), and Cu(III)).…”

Section: Introductionmentioning

confidence: 99%

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

Reen

Kumar

Sharma

2019

Beilstein J. Org. Chem.

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A comprehensive account of recent advances in the synthesis of imidazopyridines, assisted through transition-metal-catalyzed multicomponent reactions, C–H activation/functionalization and coupling reactions are highlighted in this review article. The basic illustration of this review comprises of schemes with concise account of explanatory text. The schemes depict the reaction conditions along with a quick look into the mechanism involved to render a deep understanding of the catalytic role. At some instances optimizations of certain features have been illustrated through tables, i.e., selectivity of catalyst, loading of the catalyst and percentage yield with different substrates. Each of the reported examples has been rigorously analyzed for reacting substrates, reaction conditions and transition metals used as the catalyst. This review will be helpful to the chemists in understanding the challenges associated with the reported methods as well as the future possibilities, both in the choice of substrates and catalysts. This review would be quite appealing to a wider range of organic chemists in academia and industrial R&D sectors working in the field of heterocyclic syntheses. In a nutshell, this review will be a guiding torch to envisage: (i) the role of various transition metals in the domain dedicated towards method development and (ii) for the modifications needed thereof in the R&D sector.

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“…41 Also, glucose was found an applicable additive for reactions catalyzed by copper oxide/alumina in heterogeneous strategies. 42 It is noteworthy that Mishra and Ghosh 43 reported the use of CuI and NaHSO 4 .SiO 2 as binary catalysts, a semi-heterogeneous approach.They have also proved the necessity of both Lewis and Brϕnsted acids in the reaction media to efficiently perform cycloisomerization. Another report by Corma and co-workers 44 shows the ability of Cu II -MOF (MOF: metal-organic framework) on catalyzing the same reaction by a combination of the adsorbed Lewis acid on a microporous and flexible framework.…”

Section: Introductionmentioning

confidence: 99%

Imidazo[1,2-a]pyridine A3-Coupling Catalyzed by a Cu/SiO2 Material

Salles¹,

Silva²,

Radatz³

et al. 2019

J. Braz. Chem. Soc.

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In this work, we report the preparation of a copper-silica material (Cu/SiO 2) by a sol-gel methodology and its characterization concerning composition and textural properties. The Cu/SiO 2 material was successfully applied as a Lewis acid heterogeneous catalyst for the A 3-coupling from 2-aminopyridine, aldehydes and alkynes to imidazo[1,2-a]pyridines (45-82%), which are relevant pharmacological scaffolds. The synthesis shows a number of advantages, such as easy separation from the reaction media and the minimal formation of metal aqueous wastes. Investigation of the mechanism supports the involvement of the formation of reaction intermediates inside the pores of the mesoporous material prior to 5-exo-dig cyclization.

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CuO–CuAl2O4 and d-glucose catalyzed synthesis of a family of excited state intramolecular proton transfer imidazo[1,2-a]pyridine analogues and their optical properties

Cited by 27 publications

References 43 publications

Structural, energetic and spectroscopic studies of new luminescent complexes based on 2-(2′-hydroxyphenyl)imidazo[1,2-a]pyridines and 1,2-phenylenediboronic acid

Structural, energetic and spectroscopic studies of new luminescent complexes based on 2-(2′-hydroxyphenyl)imidazo[1,2-a]pyridines and 1,2-phenylenediboronic acid

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

Imidazo[1,2-a]pyridine A3-Coupling Catalyzed by a Cu/SiO2 Material

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