Browsing by Author "Upendra Kumar Patel"

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1,2,3-Triazole-tethered fluoroquinolone analogues with antibacterial potential: synthesis and in vitro cytotoxicity investigations
(Royal Society of Chemistry, 2025) Upendra Kumar Patel; Alka; Punit Tiwari; Ragini Tilak; Gaurav Joshi; Roshan Kumar; Alka K. Agarwal
The antibacterial efficacy of some newly developed bis- and C3-carboxylic moieties of fluoroquinolone-linked triazole conjugates was studied. Twenty compounds from two different series of triazoles were synthesized using click chemistry and evaluated for their antibacterial activity against a Gram-positive strain, i.e. Enterococcus faecalis (ATCC29212), and its clinical isolate and a Gram-negative bacterial strain, i.e. Escherichia coli (ATCC25922), and its clinical isolate. Among the compounds, 7, 9a, 9d, 9i, 10(a–d), and 10i showed excellent activity with MIC values of up to 6.25 mg mL−1, whereas the control ciprofloxacin showed MIC values of up to 12.5 mg mL−1 towards the various strains. Cytotoxicity was evaluated against Vero cells (kidney epithelial cells of an African green monkey), and results revealed that compounds 9a, 9c, 10g, 10h, and 10 are toxic. Molecular docking and MD analysis were performed using the protein structure of E. coli DNA gyrase B and further corroborated with an in vitro assay to evaluate the inhibition of DNA gyrase. The analysis revealed that compound 10d was a more potent inhibitor of DNA gyrase compared to ciprofloxacin, which was employed as the positive control. © 2025 The Author(s).
Carbocatalytic Activity of Graphene Oxide in Organic Transformations: A Comprehensive Review
(John Wiley and Sons Inc, 2025) Alka; Upendra Kumar Patel; Alka K. Agarwal
This review article provides a detailed summary of the current advances in the field of heterogeneous catalysis using graphene oxide. The applications of graphene oxide have received a lot of attention over the past few years. The simple synthetic protocols and their green chemistry approach have increased the popularity of novel nanocatalysts. Because of its unique properties, graphene oxide (GO) has become one of the most fascinating and extensively studied materials. Scientists have found a variety of inimitable optical, electrical, and chemical characteristics in graphene oxide which can be utilized in diverse applications. Graphene oxide as a 2D framework adorned with oxygen-containing functional groups possesses rich chemical properties and may present a green alternative to precious metal catalysts. The catalytic organic transformations extensively use graphene oxide (GO) as a metal-free and easily accessible carbocatalyst. This article primarily discusses the synthesis of GO and its utilization in reactions involving oxidation such as oxidative coupling and oxydehydrogenation reactions, functional group modifications, such as the oxidation of hydroxyl (─OH) group and boronic acid, oxidative halogenations, Friedel–Crafts reactions, condensation reactions, and other reactions. © 2025 Wiley-VCH GmbH.
Challenges and Recent Advances of Novel Chemical Inhibitors in Medulloblastoma Therapy
(Humana Press Inc., 2022) Anand Maurya; Upendra Kumar Patel; Jitendra Kumar Yadav; Virender Pratap Singh; Alka Agarwal
Medulloblastoma is a common term used for the juvenile malignant brain tumor, and its treatment is exciting due to different genetic origins, improper transportation of drug across the blood-brain barrier, and chemo-resistance with various side effects. Currently, medulloblastoma divided into four significant subsections (Wnt, Shh, Group 3, and Group 4) is based on their hereditary modulation and histopathological advancement. In this chapter, we tried to combine several novel chemical therapeutic agents active toward medulloblastoma therapy. All these compounds have potent activity to inhibit the medulloblastoma. © 2022, The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.
Ciprofloxacin-Tethered 1,2,3-Triazole Conjugates: New Quinolone Family Compounds to Upgrade Our Antiquated Approach against Bacterial Infections
(American Chemical Society, 2022) Alka Agarwal; Preeti Singh; Anand Maurya; Upendra Kumar Patel; Alka Singh; Gopal Nath
A newer ciprofloxacin series containing 1,2,3-triazole conjugates of ciprofloxacin was designed, synthesized, and well characterized using modern analytical techniques by reacting diversified anilines with ciprofloxacin obtained from ciprofloxacin hydrochloride. The newer conjugates were evaluated for their antimicrobial activity against various strains, viz. Staphylococcus aureus (ATCC25923), Enterococcus faecalis (clinical isolate), Staphylococcus epidermidis (ATCC3594), Escherichia coli (ATCC25922), Pseudomonas aeruginosa (ATCC27853), Salmonella typhi (clinical isolate), Salmonella typhimurium (clinical isolate), Acinetobacter baumannii (ATCC19606), Aeromonas hydrophila (ATCC7966), Plesiomonas shigelloides (ATCC14029), and Sphingo biumpaucimobilis (MTCC6362) in vitro. Interestingly, some of the conjugates showed superior antimicrobial activity as compared to the control drug ciprofloxacin. The three compounds 4i, 4j, and 4n showed strong activity with minimum inhibitory concentration (MIC) 0.78 μM, while the compound 4g showed MIC 1.56 μM against S. typhi (clinical). The compound 4a showed good efficacy against S. aureus (ATCC25923) and S. typhi (clinical) with MIC 3.12 μM, while the compound 4b exhibited efficacy with MIC 3.12 μM against S. aureus (ATCC25923) and the control drug ciprofloxacin showed MIC 6.25 μM. Among all of the synthesized compounds, 4e, 4f, 4g, 4h, 4p, 4q, 4t, and 4u displayed less than 20% hemolysis, while the rest of the compounds showed hemolysis in the range of 21–48%. Moreover, the structure of compound 4b was also established by single-crystal X-ray diffraction studies. © 2022 The Authors. Published by American Chemical Society
Design and synthesis of new benzimidazole-hybrids as anti-microbial agents: exploring the mechanistic insights as DNA gyrase inhibitors via in silico and in vitro based studies
(Taylor and Francis Ltd., 2025) Anand Prakash Maurya; Upendra Kumar Patel; Punit Tiwari; Gaurav Joshi; Roshan Kumar; Ragini Tilak; Alka K. Agarwal
Two series of antibacterial agents, 1,2,3-triazole and aminopyrimidine benzimidazole hybrids, were designed, synthesized, and characterized by IR, NMR, Mass spectroscopy, and X-ray crystallography studies. The biological studies revealed that compounds 5a, 5b, 5c, 5d, 5e, 5f, 5g, 5h, 8d, 8e, 9d, 9e, 9f, 9h, 9j, and 9k exhibited significant antibacterial activity in vitro compared to the standard drug ciprofloxacin, against Gram-positive and Gram-negative bacterial strains. The study of hemotoxicity displayed a negligible toxicity profile for all the compounds. Furthermore, the mechanistic insights predicted via molecular docking studies on DNA gyrase revealed (Glide Scores) that compounds 5c and 5f possess better affinity within the active domain of DNA gyrase, which was further corroborated using molecular dynamics followed by direct DNA gyrase-based inhibition assays. Compound 5f was the most potent, while 5c showed an equipotent inhibition compared to a standard drug. © 2025 Informa UK Limited, trading as Taylor & Francis Group.
Endoperoxides as Antimalarials: Development, Structural Diversity, and Pharmacodynamic Aspects of 1,2,4,5-Tetraoxane-Based Structural Scaffolds
(Georg Thieme Verlag, 2025) Upendra Kumar Patel; Alka Alka; Alka K. Agarwal
Malaria poses a serious threat to human life and is prevalent in tropical and subtropical areas across the globe. Drugs such as quinine, chloroquine (a synthetic version of quinine), artemisinin, and its derivative compounds have been used to treat malaria. Developing highly effective chemical scaffolds with minimal toxicity is necessary because malarial parasites have become resistant to existing drugs. In this context, 1,2,4,5-tetraoxanes have emerged as a crucial framework with notable antimalarial properties. To improve the effectiveness and combat resistance to various antimalarial drugs, 1,2,4,5-tetraoxanes have been combined with a variety of alicyclic, aryl, heteroaryl, and spiro groups including steroid-based, aminoquinoline-based, dispiro-based, triazine-based, diaryl-based, and piperidine-based 1,2,4,5-tetraoxanes. We provide an overview of the synthesis and most important in vitro and in vivo investigations carried out on hybrids based on 1,2,4,5-tetraoxane as antimalarial drugs. The future development of malaria treatment may be influenced by the structural changes in different hybrids of 1,2,4,5-tetraoxane. 1 Introduction 2 Synthetic Methods for Tetraoxanes 3 Antimalarial Activities of Tetraoxane Derivatives 3.1 Cycloalkanone-Based Tetraoxanes 3.2 Steroid-Based Tetraoxanes 3.3 Adamantane-Based Tetraoxanes 3.4 Dispiro-Based Tetraoxanes 3.5 Diaryl-Based Tetraoxanes 3.6 Di-adamantane-Based Tetraoxanes 3.7 Benzylamino- and Aryloxy-Based Tetraoxanes 3.8 Aminoquinoline-Based Tetraoxanes 3.9 2-Cyanopyrimidine-Based Tetraoxanes 4 Mannich Base Based Tetraoxanes 4.1 N -Sulfonylpiperidine-Based Tetraoxanes 4.2 N -Benzoylpiperidine-Based Tetraoxanes 5 Mechanism of Action of Dispiro-1,2,4,5-tetraoxanes 6 Conclusion. © 2025. The Author(s). SynOpen.
Molybdenum trioxide as a newer diversified economic catalyst for the transformation of nitroarenes to arylamine and 5-substituted-1H-tetrazole
(Royal Society of Chemistry, 2024) Anand Maurya; Upendra Kumar Patel; Sanjeev Kumar; Alka Agarwal
The present work has developed a straightforward, gentle, and effective approach for synthesizing arylamines and 5-substituted-1H-tetrazole derivatives, and among the two tested catalysts, molybdenum trioxide (MoO3) proved to be highly effective. The selective hydrogenation of nitroarenes to arylamines presents a significant challenge due to the complex reaction mechanism and the competitive hydrogenation of other reducible functional groups. It facilitated the transfer hydrogenation of nitrobenzene using hydrazine hydrate-produced amino compounds and enabled the [3 + 2] cycloaddition of sodium azide with aromatic nitriles to yield 5-substituted-1H-tetrazoles. The structure of compound 5-(4-bromophenyl)-1H-tetrazole (5k) was verified through single-crystal X-ray analysis, and the calculation of Green Chemistry Metrics showed the optimal range. Notably, the MoO3 catalyst can be reutilized for up to seven cycles with minimal loss of effectiveness. These attributes make molybdenum trioxide particularly attractive for industrial applications. This methodology offers several advantages over traditional synthetic methods. © 2024 The Royal Society of Chemistry.
Sustainable Design and Revolutionary Synthesis of Highly Recyclable Sulfonic Acid–Based Magnetic Nanoparticles as a Solid Acid for Synthesis of 2-Substituted Benzimidazole and Bis Indole Methane Derivatives
(John Wiley and Sons Ltd, 2025) Alka; Upendra Kumar Patel; Alka K. Agarwal
Concerning the objectives of green chemistry, silica-coated magnetite nanoparticles provide a new way to implement an efficient and effective system for assisting catalyst recovery across multiple organic reactions. With Fe3O4 spheres serving as the core shell, the synthesis of sulfonic acid-functionalized silica-coated magnetic nanoparticles is presented in this paper. FTIR, PXRD, SEM, TEM, EDX, TGA, XPS, and VSM techniques were used to assess the prepared catalyst. The proposed nanocatalyst was employed to produce biological relevance 2-substituted benzimidazole and bis indole methane derivatives. High yield, quick reaction time, soothing reaction conditions, extended functional group tolerance, and an accessible workup approach are the main advantages of synthesized nanoparticles. Furthermore, the present nanocatalyst may be recovered using an external magnet and retaining its effectiveness for up to six cycles. These are distinctive functions of the present approach. © 2024 John Wiley & Sons Ltd.
Synthesis of ciprofloxacin-linked 1,2,3-triazole conjugates as potent antibacterial agents using click chemistry: exploring their function as DNA gyrase inhibitors via in silico- and in vitro-based studies
(Royal Society of Chemistry, 2024) Upendra Kumar Patel; Punit Tiwari; Ragini Tilak; Gaurav Joshi; Roshan Kumar; Alka Agarwal
The antibacterial efficacy of some newly developed C-3 carboxylic group-containing ciprofloxacin-linked 1,2,3-triazole conjugates was studied. Twenty-one compounds from three different series of triazoles were synthesized using click chemistry and evaluated for their antibacterial activity against nine different pathogenic strains, including three Gram-positive strains, i.e. Enterococcus faecalis (ATCC29212), Staphylococcus aureus (ATCC25923), Staphylococcus epidermidis (clinical isolate), and six Gram-negative bacterial strains, i.e. Escherichia coli (ATCC25922), Pseudomonas aeruginosa (ATCC27853), Salmonella typhi (clinical isolate), Proteus mirabilis (clinical isolate), Acinetobacter baumannii (clinical isolate) and Klebsiella pneumonia (clinical isolate). Among the compounds, 10, 10a, 10b, 10c, 10d, 11a, 11f, 12c, 12e and 12f showed excellent activity with MIC values upto 12.5 μg mL−1, whereas the control ciprofloxacin showed MIC values of 0.781-25 μg mL−1 towards various strains. In addition, the low toxicity profile of the synthesized molecules revealed that they are potent antibiotics. Molecular docking and MD analysis were performed using the protein structure of E. coli DNA gyrase B, which was further corroborated with an in vitro assay to evaluate the inhibition of DNA gyrase. The analysis revealed that compound 10b was the most potent inhibitor of DNA gyrase compared to ciprofloxacin, which was employed as the positive control. Furthermore, the structure of two title compounds (11a and 12d) was characterized using single-crystal analysis. © 2024 The Royal Society of Chemistry.
Synthesis of nitrogen (N) and copper oxide (CuO) co-doped reduced graphene oxide as an efficient nanocatalyst for reduction of nitroarenes and synthesis of 1, 8-dioxodecahydroacridine derivatives
(Elsevier Ltd, 2025) Alka; Upendra Kumar Patel; Alka K. Agarwal
The present study focuses on developing a robust reduced graphene oxide-based heterogeneous catalyst by synthesizing it with the doping of nitrogen (N) and copper oxide (CuO). Various techniques were used to characterize the green catalyst, such as FTIR, PXRD, TGA, RAMAN, TEM, SEM, and EDX. The catalyst was utilized in the production of various biologically important aniline derivatives through the reduction of nitroarenes with NaBH4 and the synthesis of 1,8-dioxodecahydroacridine derivatives via one-pot, multi-component condensation of dimedone, various aromatic aldehydes, and anilines / NH4OAc. Some key features of the current catalytic system include a high yield (up to 96 % and 97 %, respectively), quick reaction time (20 min and 1 h, respectively), low catalyst loading (10 mg for each), broad functional group tolerance, and a simple work-up process. © 2025 Elsevier B.V.