Tautomerism in pyridazin-3(2H)-one: A theoretical study using implicit/explicit solvation models

Emamian, Saeedreza; Domingo, Luís R.; Tayyari, Sayyed Faramarz

doi:10.1016/j.jmgm.2014.01.006

Cited by 26 publications

(21 citation statements)

References 39 publications

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“…44 kcal/mol, and thus, the N-O cleavage via a 1,2-hydrogen shift is kinetically very unfavourable. The high strain energy associated with the formation of a three membered ring along the intramolecular 1,2-hydrogen shift is responsible for the unfeasibility of the intramolecular process [17]. This fact is in complete agreement with the experimental results herein reported and allows the singlepot procedure of this domino reaction to be ruled out.…”

Section: (Ii) Study Of the Mechanism Of The Pt(ii)-catalysed 32ca Reasupporting

confidence: 90%

Synthesis, molecular structure and stability of fused bicyclic Δ4-1,2,4-oxadiazoline Pt(II) complexes

et al. 2015

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Section: (Ii) Study Of the Mechanism Of The Pt(ii)-catalysed 32ca Reasupporting

confidence: 90%

Synthesis, molecular structure and stability of fused bicyclic Δ4-1,2,4-oxadiazoline Pt(II) complexes

et al. 2015

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“…Such an approach has been employed in several studies. Emamian et al studied the solvent effect on the tautomerization of pyridazinone into pyridazole by combining explicit and solvation models and highlighted the significance of explicit solvent molecules involved in six or higher membered TSs in reducing the activation barriers [22]. Chahkandi et al investigated the effect of 1-3 water assisted molecules on the activation energies of the tautomerism reaction of 1,3,4-oxadiazole derivatives and found that the energy barriers were strongly reduced in presence of water molecules [23].…”

Section: Resultsmentioning

confidence: 99%

Antioxidant Activity of Hispidin Oligomers from Medicinal Fungi: A DFT Study

et al. 2014

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Hispidin oligomers are styrylpyrone pigments isolated from the medicinal fungi Inonotus xeranticus and Phellinus linteus. They exhibit diverse biological activities and strong free radical scavenging activity. To rationalize the antioxidant activity of a series of four hispidin oligomers and determine the favored mechanism involved in free radical scavenging, DFT calculations were carried out at the B3P86/6-31+G (d, p) level of theory in gas and solvent. The results showed that bond dissociation enthalpies of OH groups of hispidin oligomers (ArOH) and spin density delocalization of related radicals (ArO • ) are the appropriate parameters to clarify the differences between the observed antioxidant activities for the four oligomers. The effect of the number of hydroxyl groups and presence of a catechol moiety conjugated to a double bond on the antioxidant activity were determined. Thermodynamic and kinetic studies showed that the PC-ET mechanism is the main mechanism involved in free radical scavenging. The spin density distribution over phenoxyl radicals allows a better understanding of the hispidin oligomers formation.

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“…Based on previous reports that confirm the existence of acyl and aroylhydrazones in polar solvents (such as DMSO solutions) up to 100% as E -isomers [ 56 ], the Z -isomers are excluded in this study. On the other hand, many reports have studied the amide-amidic acid tautomerism of amides and anilides [ 57 , 58 , 59 , 60 , 61 ]. However, to the best of our knowledge, there are no literature reports studying amido-amidic acid tautomerism for acylhydrazones.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, DFT Molecular Geometry and Anticancer Activity of Symmetrical 2,2′-(2-Oxo-1H-benzo[d]imidazole-1,3(2H)-diyl) Diacetate and Its Arylideneacetohydrazide Derivatives

et al. 2022

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To identify new candidate anticancer compounds, we here report the synthesis of benzimidazole derivatives: diethyl 2,2′-(2-oxo-1H-benzo[d]imidazole-1,3(2H)-diyl) diacetate and its arylideneacetohydrazide derivatives, using ultrasonic irradiation and conventional heating. The compounds were confirmed by Nuclear magnetic resonance (NMR) (JEOL, Tokyo, Japan) and Fourier transform infrared spectroscopy (FTIR) spectroscopy (Thermoscientific, Waltham, MA, USA). The molecular structure and electronic properties of the studied compounds were predicted for the acetohydrazide hydrazones. These compounds exist as a mixture of configurational and conformational isomerism as well as amido-amidic acid tautomerism. The NMR spectral data proved the predominance of syn-E amido isomers. In addition, density functional theory (DFT) predicted stability in the gas phase and showed that syn-E amido isomers are the most stable in the presence of an electron donating group, while the anti-isomer is the most stable in the presence of electron-attracting substituents. The anticancer activity of these synthetic compounds 6a, 6b and 6c towards both colon cancer (HCT-116) and cervical cancer (HeLa) cells was examined by MTT assay and DAPI staining. The MTT assay revealed a strong antiproliferative effect against the cancer cells at low concentrations, and interestingly, no significant inhibitory action against the non-cancerous cell line, HEK-293. The IC50 values for HCT-116 were 29.5 + 4.53 µM, 57.9 + 7.01 µM and 40.6 + 5.42 µM for 6a, 6b, and 6c, respectively. The IC50 values for HeLa cells were 57.1 + 6.7 µM, 65.6 + 6.63 µM and 33.8 + 3.54 µM for 6a, 6b, and 6c, respectively. DAPI staining revealed that these synthesized benzimidazole derivatives caused apoptotic cell death in both the colon and cervical cancer cells. Thus, these synthetic compounds demonstrate encouraging anticancer activity as well as being safe for normal human cells, making them attractive candidates as anticancer agents.

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Tautomerism in pyridazin-3(2H)-one: A theoretical study using implicit/explicit solvation models

Cited by 26 publications

References 39 publications

Synthesis, molecular structure and stability of fused bicyclic Δ4-1,2,4-oxadiazoline Pt(II) complexes

Synthesis, molecular structure and stability of fused bicyclic Δ4-1,2,4-oxadiazoline Pt(II) complexes

Antioxidant Activity of Hispidin Oligomers from Medicinal Fungi: A DFT Study

Synthesis, DFT Molecular Geometry and Anticancer Activity of Symmetrical 2,2′-(2-Oxo-1H-benzo[d]imidazole-1,3(2H)-diyl) Diacetate and Its Arylideneacetohydrazide Derivatives

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