Browsing by Author "Rashmi Dubey"

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2-Substituted-8-methyl-3,6-dihydroimidazo[4,5-c]pyrazolo[3,4-e] pyridazine as an anti-inflammatory agent
(2011) Ashish Kumar Tewari; Rashmi Dubey; Anil Mishra
A series of 8-methyl-2-substituted-3,6-dihydroimidazo[ 4,5-c]pyrazolo[3,4- e]pyridazine compounds have been synthesized in the present investigation utilizing Philips condensation (Philips, J Chem Soc 2393-2399, 1928). The anti-inflammatory activity of the synthesized compounds was evaluated using a carrageenin rat model. © Springer Science+Business Media, LLC 2010.
Conformation of (-)/(l)-1,3-bis(4,6-dimethyl-1H-nicotinonitril-1-yl)1,3- dithioxypropane stabilized via intra/intermolecular weak interactions
(2011) Rashmi Dubey; Ashish Kumar Tewari; K. Ravikumar; B. Sridhar
In solution state, the stable gauche conformation of 1,3-bis(4,6-dimethyl- 1H-nicotinonitril-1-yl)1,3-dithioxypropane is predicted by CD spectra. Weak interaction present in the molecule makes it flexible, and due to this reason helicity is observed in it. In solid state, the molecular conformation and packing geometry is stabilized via both intra/inter molecular CH•••N, CH•••S and π•••π interactions. © 2011 Springer Science+Business Media, LLC.
Conformational tuning of molecular network stabilized via C-H...π and π-π interaction in 2-[2-(3-cyano-4, 6-dimethyl-2-oxo-2H-pyridin-1-yl- methyl)-benzyloxy]-4, 6-dimethylnicotinonitrile
(Arkat, 2009) Ashish K. Tewari; Rashmi Dubey
2-[2-(3-Cyano-4,6-dimethyl-2-oxo-2H-pyridin-1-ylmethyl)benzyloxy]-4, 6-dimethyl- nicotinonitrile (1) has been synthesized and characterized by 1H and 13C NMR. In solid state, the molecular conformation of sterically hindered compound (1) is stabilized in such a way that gauche conformation is attained by both heterocyclic rings with respect to phenyl ring via intramolecular CH-O and CH-π interactions. The weak CH-X (π, O, N) interactions manifest an interesting role in stabilizing the packing mode of compound. X-ray crystal structure of compound shows a cavity of 13 members formed via intramolecular CH-π interaction.
Emerging trends in molecular recognition: Utility of weak aromatic interactions
(2008) Ashish Kumar Tewari; Rashmi Dubey
Aromatic interactions play a vital role in chemistry and biology. As about 20% are aromatic in nature, so the role of aromatic interactions become prominent in drug receptor interactions. Not only in drug receptor interactions but also in crystal engineering, protein folding, stacking interactions in DNA/RNA the role of the interactions is of utmost importance. With the emergence of supramolecular chemistry dendrimers, tweezers, rotaxanes, catenanes, and several supramolecular aggregates are associated with aromatic interactions. The mechanism of such interactions is still unknown by the replacement of a small substituent from the aromatic molecule may lead or destroy the interactions. In the present review several models are being discussed with arene interactions under selected heads. © 2007 Elsevier Ltd. All rights reserved.
Erratum: 2-Substituted-8-methyl-3,6-dihydroimidazo [4,5-c]pyrazolo[3,4-e]pyridazine as an anti-inflammatory agent (Medical Chemistry Research DOI: 10.1007/s00044-010-9452-9)
(Birkhauser Boston, 2011) Ashish Kumar Tewari; Rashmi Dubey; Anil Mishra
[No abstract available]
Existing pharmacological challenges and the need for improved therapies
(Elsevier, 2025) Rashmi Dubey; Sudhir Kumar Kumar Pandey; Triratnesh Gajbhiye; Mohineeta Pandey; Ankesh Tiwari; Ashish Kumar Tewari
Effective diabetes management is crucial for preventing both acute and long-term complications, improving quality of life, and reducing the economic burden associated with the disease. For this purpose, targeting specific enzymes involved in glucose metabolism could be a useful therapeutic technique. Enzyme inhibitors, enzyme replacement treatment, and gene therapy are among the topics being researched. Regular monitoring, medication adherence, a healthy lifestyle, and ongoing medical care are critical components of effective diabetes management. It is important for individuals with diabetes to work closely with their healthcare team to develop and implement a personalized management plan. © 2025 Elsevier Inc. All rights reserved.
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.
Medicinally important constituents of tulsi (Ocimum spp.)
(Elsevier, 2018) Rashmi Dubey; Sudhir Kumar Pandey
The medicinal potential of a highly important Indian medicinal plant Tulsi (Ocimum spp.) has been evaluated with respect to isolation of bioactive agents, the synthesis of important derivatives, and the bioactivity of isolated/synthesized derivatives toward cure of various human ailments. To this end, isolation strategies for important bioactive agents from different parts of this plant have been emphasized that includes essential oils, eugenol, ursolic acid, etc. Then, the efficacy of different synthetic schemes of important derivatives of these isolated bioactive compounds has been discussed and critically evaluated. Finally, the bioactivity potential of important compounds/derivatives of Tulsi has been evaluated against several diseases and health problems such as immunomodulatory effects, cardiovascular disease risk factors, antidiabetic property, stress resilience, headache treatment and psychological disorders, against kidney stones, antiinflammatory disorders, antimicrobial, antifertility effect, antioxidant activity, anticoagulant activity, thyroid activity, respiratory disorders, toothache, antiulcerogenic, and for nutrient as well. At the end, the current status of research on Tulsi and its importance as medicine for a number of health problems has been critically assessed and future perspectives are highlighted. © 2018 Elsevier Ltd. All rights reserved.
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.
Polymorphic signature of the anti-inflammatory activity of 2,2′-{[1,2-Phenylenebis(methylene)]bis(sulfanediyl)}bis(4, 6-dimethylnicotinonitrile)
(2014) Rashmi Dubey; Praveen Singh; Ajeet K. Singh; Manoj K. Yadav; D. Swati; Manjula Vinayak; Carmen Puerta; Pedro Valerga; K. Ravi Kumar; B. Sridhar; Ashish K. Tewari
Weak noncovalent interactions are the basic forces in crystal engineering. Polymorphism in flexible molecules is very common, leading to the development of the crystals of same organic compounds with different medicinal and material properties. Crystallization of 2,2′-{[1,2-phenylenebis(methylene)] bis(sulfanediyl)}bis(4,6-dimethylnicotinonitrile) by evaporation at room temperature from ethyl acetate and hexane and from methanol and ethyl acetate gave stable polymorphs 4a and 4b, respectively, while in acetic acid, it gave metastable polymorph 4c. The polymorphic behavior of the compound has been visualized through single-crystal X-ray and Hirshfeld analysis. These polymorphs are tested for anti-inflammatory activity via the complete Freund's adjuvant-induced rat paw model, and compounds have exhibited moderate activities. Studies of docking in the catalytic site of cyclooxygenase-2 were used to identify potential anti-inflammatory lead compounds. These results suggest that the supramolecular aggregate structure, which is formed in solution, influences the solid state structure and the biological activity obtained upon crystallization. © 2014 American Chemical Society.
Quantitative intermolecular interactions analysis for amide-amide hydrogen-bonded synthons: Insilico studies for Cox-2 selective inhibitors
(Elsevier B.V., 2023) Akhilesh Kumar; Ranjeet Kumar; Rashmi Dubey; Manisha Nidhar; Indresh Verma; Praveen Singh; Ashish Kumar Tewari
Synthesis and characterization of diaryl fragment based pyridazine and triazine derivatives containing amide functional group have been carried out for the studies of amide-amide hydrogen-bonded synthons formation. The supramolecular synthons formations in solid state have been carried out by x-ray crystallography and Hirshfeld surface analysis. The crystal structure and Hirshfeld surface analysis have shown that synthons formation takes place by N-H⋯O interactions as well as some other interactions that stabilized the molecules. Further, insilico studies have been carried out for COX-2 selective Inhibitor. © 2023
Studies of inter/intramolecular weak interactions with CH⋯S and S⋯arene interaction in symmetrical and dissymmetrical models
(2010) Rashmi Dubey; Ashish K. Tewari; K. Ravikumar; B. Sridhar
Evidences have proved the versatile role of sulfur atom in supramolecular chemistry.1 Presence of S atom in the molecule usually results in the specific structural properties of molecules. In the present study, S⋯arene, N⋯arene, CH⋯π, CH⋯ S and CH⋯N type of weak interactions stabilize the conformation and self assembly of symmetrical as well as dissymmetrical molecules.
Weak interactions: A versatile role in aromatic compounds
(Bentham Science Publishers, 2011) Rashmi Dubey; Dongyeol Lim
Aromatic interactions are essential for stabilizing the conformation and crystal packing of molecules. They also play a vital role in drug chemistry by mediating drug-receptor interactions. In the present review, we discuss the various fields in which aromatic interactions are important and the role of such interactions. © 2011 Bentham Science Publishers Ltd.
Weak interactions: Potency for stabilization of molecule in solid state
(2011) Rashmi Dubey; Ashish Kumar Tewari; K. Ravikumar; B. Sridhar
Weak interactions usually show a versatile property to stabilize the molecular conformation and crystal packing in solid state. Crystal packing and conformational property of the synthesized compound 1(3-cyano-4,6-dimethyl nicotinonitril-1-yl)-3-(phalimido-1-yl)-1-thioxyethane (2) is stabilized by CH⋯O, CH⋯N, and CH⋯π interactions. © 2011 HeteroCorporation.