Browsing by Author "Ved Prakash Singh"

Now showing 1 - 15 of 15

A new polymorph of 4,4′-(ethyl-enedi-oxy)dibenzaldehyde
(2007) Ashish Kumar Tewari; Ved Prakash Singh; Carmen Puerta; Pedro Valerga
The crystal structure of a new crystalline form of 4,4′-(ethyl-enedi- oxy)dibenzaldehyde, C16H14O4, has been determined in the space group Cc using low-temperature X-ray diffraction data. The two phenyl rings have a dihedral angle of 76.03 (6)°, in contrast to their near-coplanarity in the previously reported polymorph. © International Union of Crystallography 2007.
Base-mediated regio- and stereoselective intermolecular addition of alkynes to N-heterocycles
(2011) Akhilesh Kumar Verma; Megha Joshi; Ved Prakash Singh
The regio- and stereoselective addition of N-heterocycles to alkynes using KOH is reported. Formation of (Z)-isomers and their conversion to (E)-products were found to be dependent upon time as well as the choice of base. Selective attack of N-heterocycles on a more electrophilic alkynyl carbon was supported by DFT calculations, and the stereochemistry of the products was established by X-ray crystallographic studies and intramolecular cyclization of ortho-haloalkynes in indolo-[2,1-a]isoquinolines. © 2011 American Chemical Society.
Design, synthesis, and molecular modeling of heterodimer and inhibitors of α-amylase as hypoglycemic agents
(Institute for Ionics, 2023) Ved Prakash Singh; Manisha Nidhar; Pratima Yadav; Ranjeet Kumar; Priyanka Sonker; Ashish Kumar Tewari
A series of rosiglitazone-based heterodimers were designed and synthesized, and their α-amylase and antioxidant activity was evaluated. The binding mode of the compounds at the active site of PPARγ and α-amylase enzyme was explored using MolDock docking method. In molecular docking studies against crystal structure of PPARγ (PDB code: 1FM6), compounds 10 and 13 showed interaction with amino acids Arg379, Asp379, Asn385, Ala387, Glu388, Val389, Glu390, and Lys438. Docking results of α-amylase enzyme (PDB code: 5EOF) with compounds 10 and 13 showed excellent interaction with amino acids Ala169, Lys172, Asp173, Tyr174, Val175, Arg176, and Lys178. Depending on the docking score, the designed compounds were selectively prioritized for synthesis. All synthesized compounds were subjected to in vitro α-amylase activity and antioxidant activity. Compounds 10 and 13 were to possess higher potency than acarbose, and most of the compounds showed antioxidant activity. Additionally, the most active compound 10 was evaluated for in vivo anti-diabetic activity. Graphical abstract: [Figure not available: see fulltext.]. © 2022, The Author(s), under exclusive licence to Springer Nature Switzerland AG.
Design, synthesis, and study of 2-pyridone-based pharmaceutical analogues
(Elsevier B.V., 2025) Lalhruaizela Lalhruaizela; Biki Hazarika; Balkaran Singh Sran; Suman K. Kushwaha; Ravindra K. Rawal; Ved Prakash Singh
2-pyridones are an important class of compounds among the N-heterocycles due to the abundant presence of their structural derivatives in many biologically active compounds. The synthesis of 2-pyridone derivatives (compounds 3A-3C) involves the condensation of aldehyde, malononitrile, and ethyl acetoacetate by a base-catalyzed reaction. Heterocyclic ring rearrangements were carried out using the simplest acid as a catalyst to produce hydroaromatic compounds, followed by dehydrogenation to yield the corresponding aromatic analogues. A sample of the crystals obtained from the synthesized compounds 3A-3C were studied to explore the types of hydrogen bonding and other intermolecular interactions involved in the supramolecular assemblies. Hirsheld surface analyses were also conducted to support the weak interactions and investigate their contributions within the supramolecular assemblies. In silico studies were also performed on the molecular recognition and ADMET properties of the compounds to reveal the most promising compounds for drug development. © 2024 Elsevier B.V.
Design, synthesis, in silico analysis with PPAR-γ receptor and study of non-covalent interactions in unsymmetrical heterocyclic/phenyl fleximer
(Chinese Chemical Society Taiwan, 2021) Ved Prakash Singh; Jayanta Dowarah; Brilliant N. Marak; Ashish Kumar Tewari
This work deals with the design, synthesis, in silico analysis, crystallization, and the interpretation 2-cyano-3-{4-[2-(phthalimid-nyl)-propoxy]-phenyl}-acrylic acid ethyl ester (7). Analog 7 is designed based on rosiglitazone. The quantitative analysis of Compound 7 has been performed through single-crystal X-Ray Diffraction (XRD) and Hirshfeld surface analysis. Fleximer 7 has studied the role of flexibility in non-covalent interactions and binding affinity with PPAR-γ receptors. Both phthalimide ring and phenyl rings are linked with propylene linker. 2-cyano-3-{4-[2-(phthalimid-nyl)-propoxy]-phenyl}-acrylic acid ethyl ester has Z = 8 in the crystal packing and stabilized by intermolecular non-covalent interactions like C-H…O, C-H…N, C-H…л, and л…л, and so forth. © 2020 The Chemical Society Located in Taipei & Wiley-VCH GmbH
Importance of weak interactions in developing 1,3-bis(4,6-dimethyl-1H- nicotinonitrile-1-yl)1,3-dioxy propane polymorphs
(2011) Ashish Kumar Tewari; Ved Prakash Singh; Rashmi Dubey; Carmen Puerta; Pedro Valerga; Rajnikant Verma
The structure of 1,3-bis(4,6-dimethyl-1H-nicotinonitrile-1-yl)1,3-dioxy propane polymorphs has been characterized by X-ray diffraction, FT-IR, 1H and 13C NMR spectroscopies. The influence of intra and intermolecular weak interactions is thoroughly studied in solid state using single crystal X-ray diffraction and FT-IR. These polymorphs belong to monoclinic space group 'P2 1/n' and 'P2 1/c'. These polymorphs have C-H⋯n (lone pair), hydrogen bonds, C-N⋯π, C-H⋯π and π⋯π intermolecular non-covalent interactions. These polymorphs are the result of weak interactions and solvent used in crystallization. The FT-IR spectra have been recorded in the solid phase and NMR has been recorded in solvent. The optimized geometry has been calculated by B3LYP methods using different basis sets. The FT-IR and NMR spectra of 1st polymorphs has been calculated at B3LYP/6-31G (d) level. The scaled theoretical wave number showed good agreement with the experimental values. These two polymorphs as well as other stereomers are studied by DFT calculations. © 2011 Elsevier B.V. All rights reserved.
Lanthanum-based double perovskite oxides as cobalt-free catalyst for bifunctional application in electrocatalytic oxygen reactions
(Elsevier Ltd, 2024) Divya Pratap Singh; Sanjukta Mukherjee; Sweta Bhagat; Nandita Singh; Monika Singh; Akhilesh Kumar Singh; Ashish Kumar Singh; Uday Pratap Azad; Suryabhan Singh; Lalrintluangi; Ved Prakash Singh
Electrochemical water splitting by use of suitable electrocatalysts is an important process to establish water as sustainable energy material. Similarly, the Oxygen reduction reaction is an important step involved in fuel cells. Hence, suitable catalysts are required for low-cost and high-performance activity towards both processes. In this work, we synthesized Cobalt-free Lanthanum-based double Perovskites oxides La0.5Sr0.5Fe0.8Cu0.2O3 and La0.5Sr0.5Fe0.8Zn0.2O3 by sol-gel method followed by calcination at different temperatures (800 °C, 900 °C and 1000 °C). Prepared double Perovskite oxide materials exhibit bifunctional catalytic activity towards both oxygen evolution reaction and oxygen reduction reaction. Calcination temperatures and composition have a significant impact on catalytic performance because of morphological control along with tuning of surface composition. Powder X-ray diffraction study has been performed to characterize the materials and phases/composition of materials was further analyzed by Rietveld refinement. The morphology of the best catalyst was analyzed by SEM, EDS mapping and XPS analysis. The catalytic performances of the catalysts were examined using electrochemical methods such as linear sweep voltammetry, cyclic voltammetry and electrochemical impedance spectroscopy in 0.1 M KOH solution. Preparation of noble-metal/cobalt-free catalysts is important finding towards establishing water as potential source for hydrogen production. © 2023 Hydrogen Energy Publications LLC
Molecular docking study of conformational polymorph: Building block of crystal chemistry
(Hindawi Publishing Corporation, 2013) Rashmi Dubey; Ashish Kumar Tewari; Ved Prakash Singh; Praveen Singh; Jawahar Singh Dangi; Carmen Puerta; Pedro Valerga; Rajni Kant
Two conformational polymorphs of novel 2-[2-(3-cyano-4,6-dimethyl-2-oxo-2H- pyridin-1-yl)-ethoxy]-4,6-dimethyl nicotinonitrile have been developed. The crystal structure of both polymorphs (1a and 1b) seems to be stabilized by weak interactions. A difference was observed in the packing of both polymorphs. Polymorph 1b has a better binding affinity with the cyclooxygenase (COX-2) receptor than the standard (Nimesulide). © 2013 Rashmi Dubey et al.
Molecular recognition phenomenon in aromatic compounds
(2013) Ashish Kumar Tewari; Priyanka Srivastava; Ved Prakash Singh; Praveen Singh; Ranjana S. Khanna
The importance of aromatic interactions has been well studied in drug designing due to the presence of naturally occurring aromatic amino acids. Aromatic interactions are, themselves, very weak interactions in the range 0-1 kcal mol-1, but these interactions, along with the other non-covalent interactions, play an important role in determining molecular recognition processes in chemistry and biology. Of course, hydrogen bonding is strong enough to provide a sufficient host and guest interaction, but in the case of aromatic systems or hydrophobic systems in absence of sites for hydrogen bonding, aromatic interactions exhibit an effect of cooperatively coming to closure to the other molecules. These forces may be electrostatic in nature, influenced by the presence of electrostatic functional groups. But, sometimes, dispersion interaction dominates over the electrostatic interaction. Thus, various factors are responsible for the existence of aromatic interactions, which are studied in the present manuscript in detail. Graphical Abstract: [Figure not available: see fulltext.] © 2012 Springer Science+Business Media Dordrecht.
Novel anti-inflammatory agents based on pyrazole based dimeric compounds; design, synthesis, docking and in vivo activity
(2010) Ashish Kumar Tewari; Priyanka Srivastava; Ved Prakash Singh; Amit Singh; Raj Kumar Goel; Chethampadi Gopi Mohan
Series of pyrazole ester prodrugs analogues have been synthesized and found to contain highly potent inhibitors of the cyclooxygenase-2 (COX-2) enzyme. The paper describes synthesis of the target pyrazole analogues. The structure of the synthesized mutual ester prodrugs (6-8c) were confirmed by 1H-, 13C-NMR mass spectroscopy (MS) and their purity were ascertained by TLC and elemental analyses. The biological in vivo evaluation of these compounds in experimental models (carrageenan-induced oedema) proved the presence of anti-inflammatory activity. Docking studies into the catalytic site of COX-2 were used to identify potential anti-inflammatory lead compounds. One lead derivative was chosen endowed with good binding energies. © 2010 Pharmaceutical Society of Japan.
Role of Tamra bhasma, an Ayurvedic preparation, in the management, of lipid peroxidation in liver of albino rats
(1996) Yamini B. Tripathi; Ved Prakash Singh
Hepatoprotective effect of Tamra bhasma has been studied on cumene hydroperoxide (CHP) induced peroxidation, reduced glutathione content and superoxide dismutase (SOD)-in rat liver homogenate. The drug was orally given for 8 days which showed significant reduction in the level of malondialdehyde (MDA) production at different concentrations of cumene hydroperoxide in vitro. Glutathione content was maintained upto seventy minutes and SOD activity was enhanced to 166%. These animals did not show any rise in serum GOT and GPT. On similar doses no histological changes were observed in liver. The results suggested that Tamra bhasma is a strong antioxidant drug and could be used in the management of lipid peroxidation with no detectable adverse effect.
Structural chemistry and anti-inflammatory activity of flexible/restricted phenyl dimers
(Springer, 2020) Ved Prakash Singh; Jayanta Dowarah; Ashish Kumar Tewari; David K. Geiger
Three phenyl dimer compounds, namely 3,3′-Diformyldiphenoxyethane (C16H14O4) (1), 1-(4-[2-(4-Acetyl-phenoxy)-ethoxy]-phenyl)-ethanone (C17H16N2O3) (2), 1-{4-[2-(4-Acetyl-phenoxymethyl)-benzyloxy]-phenyl}-ethanone (C24H22O4) (3), were obtained and fully characterized, including their crystal structure determinations. The structural properties of two compounds 4, 4′-(ethylenedioxy)dibenzaldehyde) (C16H14O4) (Tewari et al. Acta Cryst. E63:o1930, 2007) [1] (4) and 4-(2-Phenoxy-ethoxy)-benzaldehyde (C15H14O3) (Valgera et al. CCDC 710835, 2016) [2] (5) are discussed with the role of the substituent in crystal packing. In vivo, anti-inflammatory activities of all compounds were studied on Wistar strain albino rats. All the compounds exhibited anti-inflammatory activity except 5. Compounds 1, 2, 4 have shown moderate-to-intermediate effects on inhibitory properties. Compound (3) with restricted rotation in the compound-like SC-558 drug was shown to possess good inhibitory properties at 180 min. In silico analysis was performed and compared with experimental in vivo results. © 2020, Iranian Chemical Society.
Study of the structure-bioactivity of fleximers: synthesis, crystal structure, Hirshfeld surface analysis, and anti-inflammatory assays
(Elsevier B.V., 2021) Ved Prakash Singh; Jayanta Dowarah; Brilliant N. Marak; Balkaran Singh Sran; Ashish Kumar Tewari
Synthesized and natural pyridones/pyridines derivatives exhibiting diverse biological activities. 2-pyridone has lactam-lactim tautomerization like thymine and uracil bases. In this study, COX-2 target based series of pyridone/pyridine linked fleximers were designed, synthesized and studied. All analogues binding affinity with COX-2 active site were studied through molecular docking, and anti-inflammatory activity studied by in vivo analysis. Weak interactions were studied to find binding sites among analogues through crystal packing, Hirshfeld surface analysis and in silico analysis. All the analogues exhibited anti-inflammatory activity, while compound (3) is the most active analogue among the series. In contrast, since compound (3) is a pyridine-phthalimide ring-containing analogue, the presence of a phthalimide group probably favors anti-inflammatory activity over other types of rings. The results suggested further investigations on compounds as anti-inflammatory prodrugs. © 2021
Synthesis, biological evaluation and molecular modeling study of pyrazole derivatives as selective COX-2 inhibitors and anti-inflammatory agents
(Academic Press Inc., 2014) Ashish Kumar Tewari; Ved Prakash Singh; Pratima Yadav; Garima Gupta; Amit Singh; Raj Kumar Goel; Pravin Shinde; C. Gopi Mohan
A novel series of pyrazole derivatives were synthesized and evaluated in vivo for their anti-inflammatory activity in carrageenan-induced rat paw edema model. Among all compounds, 5a, and 5b showed comparable anti-inflammatory activity to Nimesulide, the standard drug taken for the studies. In silico (docking) studies were carried out to investigate the theoretical binding mode of the compounds to target the cyclooxygenase (COX-2) using Autodock 4.2. © 2014 Elsevier Inc. All rights reserved.
Water mediated self assembly of 5-(2-benzoimidazole-1-yl-ethoxy)-3-methyl- 1-phenyl-1H-pyrazole-4-carboxylic acid methyl ester through CH⋯O and OH⋯N interactions
(2012) Priyanka Srivastava; Ved Prakash Singh; Ashish Kumar Tewari; Carmen Puerta; Pedro Valerga
Single crystal X-ray structure analysis of 5-(2-benzoimidazole-1-yl-ethoxy) -3-methyl-1-phenyl-1H-pyrazole-4-carboxylic acid methyl ester (2).0.5H 2O provided experimental proof for H⋯OC, CH⋯OH and HO⋯N interactions. The embedded water molecule bridges between molecules 2 via non-covalent interactions. Thus this molecule behaves as a preorganized host molecule for water, presenting a minimum ring-size molecular environment for water binding. Single crystal X-ray structure analysis of 5-(2-benzoimidazole-1-yl-ethoxy)-3-methyl-1-phenyl-1H-pyrazole-4-carboxylic acid methyl esterhemihydrate provided experimental proof for six hydrogen bonds by one molecule of water. The embedded water molecule bridges six molecules by two types of hydrogen bonding. Theoretical calculations showed that the conformation of the bicyclic hetero-ring alters only slightly due to the presence of the water molecule. Thus this organic molecule behaves as a very interesting preorganized host molecule for water, presenting maximum binding environment for water binding. © 2011 Elsevier B.V. All rights reserved.