Browsing by Author "Mala Singh"

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1-(Hydroxymethyl)-1H-benzotriazole: An Efficient Ligand for Copper-Catalyzed Ullmann-Type Coupling Reaction Leading to Expeditious Synthesis of Diverse Benzoxazoles and Benzothiazoles
(Wiley-Blackwell, 2019) Mala Singh; Priyanka Bose; Anoop S. Singh; Vinod K. Tiwari
Cu-catalyzed Ullmann coupling was performed for the facile synthesis of diverse benzoxazoles and benzothiazoles in the presence of 1-(hydroxymethyl)-1H-benzotriazole as ligand and K2CO3 as base in anhydrous DMF at 120 0C. © 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
A new methodology for the synthesis of N-acylbenzotriazoles
(Arkat, 2017) Anoop S. Singh; Anand K. Agrahari; Mala Singh; Nidhi Mishra; Vinod K. Tiwari
A facile and economic path for an easy access of diverse N-acylbenzotriazoles from carboxylic acid has been devised using NBS/PPh3 in anhydrous dichloromethane. High yield of product was obtained at room temperature in one hour reaction time under mild reaction conditions. ©ARKAT USA, Inc
A new methodology for the synthesis of N-acylbenzotriazoles
(Arkat, 2017) Anoop S. Singh; Anand K. Agrahari; Mala Singh; Nidhi Mishra; Vinod K. Tiwari
A facile and economic path for an easy access of diverse N-acylbenzotriazoles from carboxylic acid has been devised using NBS/PPh3 in anhydrous dichloromethane. High yield of product was obtained at room temperature in one hour reaction time under mild reaction conditions. © ARKAT USA, Inc
An Improved N-Acylation of 1 H-Benzotriazole Using 2,2′-DipyridylÂ-diÂ-sulfide and Triphenylphosphine
(Georg Thieme Verlag, 2019) Anoop S. Singh; Anand K. Agrahari; Nidhi Mishra; Mala Singh; Vinod K. Tiwari
A novel path has been developed for the conversion of carboxylic acids into the corresponding N-acylbenzotriazoles by using 2,2′-dipyridyl disulfide/PPh 3 in anhydrous dichloromethane in the presence of 1 H-benzotriazole. Mild reaction conditions, short reaction time, easy in handling, wide substrate scope, availability of reagents involved, and moreover avoiding the use of base makes this protocol quite useful for the laboratory practices for N-acylbenzotriazole synthesis. © Georg Thieme Verlag Stuttgar.
Benzotriazole as an Efficient Ligand in Cu-Catalyzed Glaser Reaction
(American Chemical Society, 2019) Mala Singh; Anoop S. Singh; Nidhi Mishra; Anand K. Agrahari; Vinod K. Tiwari
Benzotriazole has been established as an efficient ligand in Cu-catalyzed cross-coupling of terminal alkynes to form 1,3-dialkynes using CuI as the catalyst and K2CO3 as the base at room temperature in an open round-bottom flask. The established protocol has the following notable advantages: simple to handle, easy work-up, mild reaction condition, high substrate scope, requirement of less quantity of ligand and also Cu-catalyst, less expensive, and high reaction yield. © 2019 American Chemical Society.
Click inspired synthesis of hexa and octadecavalent peripheral galactosylated glycodendrimers and their possible therapeutic applications
(Royal Society of Chemistry, 2019) Anand K. Agrahari; Anoop S. Singh; Ashish Kumar Singh; Nidhi Mishra; Mala Singh; Pradyot Prakash; Vinod K. Tiwari
A Cu(i)-catalyzed azide-alkyne 1,3-dipolar cycloaddition reaction (CuAAC) has been utilized for the synthesis of novel glycodendrimers containing a rigid hexapropargyloxy benzene centered core with 6- and 18-peripheral β-d-galactopyranosidic units. Structures of the novel glycodendrimers and intermediates were well elucidated using nuclear magnetic resonance and infrared spectroscopies, matrix assisted laser desorption/ionization mass spectrometry, and size-exclusion chromatography. The therapeutic evaluations of the developed glycodendrimers were investigated and they were found to have good potential as anti-bacterial, anti-biofilm, and anti-tumour agents. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2019.
Click inspired synthesis of piperazine-triazolyl sugar-conjugates as potent anti-Hela activity
(Elsevier Ltd, 2023) Priyanka Bose; Anand K. Agrahari; Rajan Singh; Mala Singh; Sunil Kumar; Rakesh K. Singh; Vinod K. Tiwari
To imbibe the aim of synthesizing water-soluble and biocompatible motif, a click-inspired piperazine glycoconjugate has been devised up. In this report, we present a focused approach to design and synthesis of versatile sugar-appended triazoles through ‘Click Chemistry’ along with their pharmacological studies on cyclin-dependent kinases (CDKs) and cell cytotoxicity on cancer cells using in silico and in vitro approaches, respectively. The study has inclusively recognized the galactose- and mannose-derived piperazine conjugates as the promising motifs. The findings suggested that the galactosyl bis-triazolyl piperazine analogue 10b is the most CDK interactive derivative and also possess significant anticancer activity. © 2023 Elsevier Ltd
Click inspired synthesis of: P-tert -butyl calix[4]arene tethered benzotriazolyl dendrimers and their evaluation as anti-bacterial and anti-biofilm agents
(Royal Society of Chemistry, 2020) Anand K. Agrahari; Ashish K. Singh; Anoop S. Singh; Mala Singh; Pathik Maji; Shivangi Yadav; Sanchayita Rajkhowa; Pradyot Prakash; Vinod K. Tiwari
Calixarenes with their three-dimensional structural architecture and ease of functionalization at the upper and/or lower rim are well-known for their plethora of applications in chemical, physical, biological and other disciplines. Herein, CuAAC click inspired p-tert-butylcalix[4]arene tethered benzotriazolyl dendrimers, for example, N-1, N-2 type 2-fold compound 6 and 7 'G(0)' and 6-fold compound 16 and 17 'G(1)' generation benzotriazolyl dendrimer, were devised and also evaluated for their therapeutic potential both in vitro and in vivo. The developed calix[4]arene tethered benzotriazolyl dendrimers have been characterized by standard spectroscopic analysis including NMR (1H and 13C), MS, and SEC. Among all the benzotriazolyl dendrimers developed, compound 7 was identified as the effective one which provided potential anti-bacterial and anti-biofilm activities against drug-resistant and slime producing organisms without imparting cytotoxicity to the eukaryotic systems. This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
Design, Synthesis, and Docking Study of Quinine-9-Triazolyl Conjugates
(John Wiley and Sons Inc, 2023) Priyanka Bose; Mala Singh; Anoop S. Singh; Manoj K. Jaiswal; Vinod K. Tiwari
To develop a better chemotherapeutically potential candidate for lung cancer treatment and cure with repurposed motifs, quinine has been linked with biocompatible CuAAC-inspired regioselective 1,2,3-triazole linker and a series of ten novel 1,2,3-triazolyl-9-quinine conjugates have been developed by utilizing click conjugation of glycosyl ether alkynes with 9-epi-9-azido-9-deoxy-quinine under standard click conditions. In parallel, the docking study indicated that the resulting conjugates have an overall appreciable interaction with ALK-5 macromolecules. Moreover, the mannose-triazolyl conjugate exhibited the highest binding interactions of −7.6 kcal/mol with H-bond interaction with the targeted macromolecular system and indicate the hope for future trials for anti-lung cancer candidates. © 2023 Wiley-VHCA AG, Zurich, Switzerland.
Design, synthesis, and docking study of saccharin N-triazolyl glycoconjugates
(Elsevier Ltd, 2024) Priyanka Bose; Mala Singh; Abhishek Gupta; Sunil Kumar; Faisal Jaah Ansari; Vinay K. Pandey; Anoop S. Singh; Vinod K. Tiwari
To achieve better-repurposed motifs, saccharin has been merged with biocompatible sugar molecules via a 1,2,3-triazole linker, and ten novel 1,2,3-triazole-appended saccharin glycoconjugates were developed in good yield by utilizing modular CuAAC click as regioselective triazole forming tool. The docking study indicated that the resulting hybrid molecules have an overall substantial interaction with the CAXII macromolecule. Moreover, the galactose triazolyl saccharin analogue 3h has a binding energy of −8.5 kcal/mol with 5 H-bonds, and xylosyl 1,2,3-triazolyl saccharin analogue 3d has a binding energy of −8.2 kcal/mol with 6 H-bond interactions and have exhibited the highest binding interaction with the macromolecule system. © 2024 Elsevier Ltd
I2/PPh3-mediated facile synthesis of glycoconjugated N-acylbenzotriazoles
(Connect Journal, 2018) Mala Singh; Anand K. Agrahari; Nidhi Mishra; Anoop S. Singh; Vinod K. Tiwari
A well-stabilized method for synthesis of N-acylbenzotriazoles from carboxylic acids using I2/PPh3 in anhydrous dichloromethane has been extended in glycochemistry to synthesize glycoconjugated N-acylbenzotriazoles with high yields at room temperature in 2-hour reaction time. © 2018 Connect Journals.
Molecular Mechanisms Underlying Breast Cancer and Role of Plant Products in Targeted Therapy
(Elsevier, 2021) Sonu Singhal; Mala Singh; Rakesh K. Singh; Vinod K. Tiwari; Surabhi Bajpai
Breast cancer (BC), the leading cause of female mortality worldwide, is caused by multiple signaling pathways. This chapter discusses major pathways underlying the cancer pathogenesis, namely, Notch pathway, Wnt/β-catenin pathway, Hedgehog pathway, NF-κB pathway, receptor tyrosine kinase pathway, Ras/MEK/Raf/ERK signaling pathway, AKT/phosphoinositide 3 kinase (PI3K) pathway, PI3Ks Class I, PI3Ks Class II and III, c-JUN NH2-terminal kinase pathway, heat shock protein 90 signaling pathway, poly(ADP-ribose) polymerase 1 signaling pathway, angiogenesis pathway, estrogen receptor signaling pathway, mammalian target of rapamycin pathway, and protein kinase C pathway. All these pathways are misregulated in BC conditions and their misregulation can be controlled by pharmacological inhibitors. Since chemical drugs or inhibitors may have some side effects and cancer cells may develop drug resistivity, a need for the study of medicinal plants, their extracts, and polyherbal formulae is warranted. Thus, this chapter is planned to focus on the various plants and their extracts that show remarkable anticancer activity. Further, it discusses about the role of pure phytochemicals like flavonoids, semisynthetic flavonoids and phenols, and polyphenols in controlling BC. This chapter will help to establish medicinal plant therapy as an effective alternative to improve the existing chemotherapy and to reduce drug-induced toxicity. © 2021 Elsevier Inc. All rights reserved.
N-Acylbenzotriazole as Efficient Ligand in Copper-Catalyzed O-Arylation Leading to Diverse Benzoxazoles
(Wiley-Blackwell, 2017) Anoop S. Singh; Mala Singh; Nidhi Mishra; Snigdha Mishra; Anand K. Agrahari; Vinod K. Tiwari
An establishment of (1H-benzo[d][1,2,3]triazol-1-yl)(2-methoxyphenyl)methanone as ligand was attained in intramolecular C-O cross-coupling of N-(2-halophenyl)aryl/alkylamide derivatives to form 2-Aryl/alkyl benzoxazole derivatives using CuI/K2CO3 as catalytic system. A series of benzoxazoles was developed using this protocol and synthesized compounds were characterized using spectroscopic analysis (IR, MS, 1H & 13C NMR). Salient advantages associated with this pathway include easily available starting materials, cheap catalyst, highly stable ligand, wide substrate scope, smooth reaction, easy work-up and high product yield. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Protocatechuic Acid and its Derivatives: Synthesis, Antioxidant Properties, and Potential In Vivo Wound Healing Applications
(John Wiley and Sons Ltd, 2025) Sumit Maurya; Sumit Manna; Mala Singh; Dharmendra Singh; Malay Nayak; Sudip Mukherjee; Arun Kumar Manna
Treatment of chronic wounds is a potential healthcare problem, affecting people globally. Traditional methods of wound healing are prone to several limitations, like infections, oxidative stress, and development of secondary wounds. Management of oxidative stress is an interesting platform to deal with chronic wounds. For this study, novel derivatives of protocatechuic acid, a naturally occurring phenolic acid, were designed by modifying the carboxylic acid moiety while preserving the hydroxyl groups for radical scavenging. So, a series of amide conjugates were synthesized by incorporating various amine moieties. Glucose conjugates were obtained through both click chemistry and direct coupling strategies and a chlorinated derivative was also prepared. The antioxidant potential of the compounds was screened using DPPH assay, followed by in vitro DCFDA assay on HEK-293T cell line. Top 5 lead molecules were checked for biocompatibility through MTT assay, which provided us with top 2 leads, Compounds 12 and 17 which were examined for a wound healing study on Wistar rats along with the starting compound 1. It was observed that Compound 17 demonstrated excellent wound tissue regeneration on day 12, as compared to the control group, suggesting the promising role of triazole and glucose moieties conjugation for relieving oxidative stress and wound management. © 2025 Wiley-VCH GmbH.
Synthesis of 1-(2-bromo-1-arylethyl)-1H-benzotriazoles via NBS promoted addition of 1H-benzotriazole to alkene: Relevance in benzotriazole ring cleavage
(Elsevier Ltd, 2020) Mala Singh; Priyanka Bose; Anoop S. Singh; Vinod K. Tiwari
A cost-effective and expeditious one-pot synthesis of 1-(2-bromo-1-arylethyl)-1H-benzotriazoles has been devised by reacting styrene and their derivatives with 1H-benzotriazole in presence of N-bromosuccinimide in anhydrous CH2Cl2 at room temperature. Further, the resulted compounds undergo E2-ellimination to afford the respective 1-(1-aryl-vinyl)-1H-benzotriazoles. At the end, 1-(1-phenylvinyl)-1H-benzotriazoles underwent benzotriazole ring cleavage (BtRC) under free radical condition to produce phenanthridine as the final product. © 2020 Elsevier Ltd
Synthesis of Benz-Fused Azoles via C-Heteroatom Coupling Reactions Catalyzed by Cu(I) in the Presence of Glycosyltriazole Ligands
(American Chemical Society, 2019) Nidhi Mishra; Anoop S. Singh; Anand K. Agrahari; Sumit K. Singh; Mala Singh; Vinod K. Tiwari
Glycosyl triazoles are conveniently accessible and contain multiple metal-binding units that may assist in metal-mediated catalysis. Azide derivatives of d-glucose have been converted to their respective aryltriazoles and screened as ligands for the synthesis of 2-substituted benz-fused azoles and benzimidazoquinazolinones by Cu-catalyzed intramolecular Ullmann type C-heteroatom coupling. Good to excellent yields for a variety of benz-fused heterocyles were obtained for this readily accessible catalytic system. © Copyright 2019 American Chemical Society.
Synthesis of glycosylated β-amino alcohols as promising antitubercular agent
(Association of Carbohydrate Chemists and Technologists, 2017) Archana Singh; Anand K. Agrahari; Mala Singh; Vishwa Deepak Tripathi; Vinod K. Tiwari
A series of novel glycosylaled β-amino alcohols has been synthesised via TBAB/NEt -catalyzed ring opening of 3 oxirane ring in D-glucose-derived 5,6-anhydro-3-O-benzyl-1,2-O-isoprpylidene-α-D-glucofuranose with different primary- and secondary amines including aliphatic, aromatic, heterocyclic, and glycosyl amine. However, the oxirane ring opening in the above anhydroglucose derivative with diamines led to the formation of respective diglycosylated N1,Nn-diaminoalcohols in excellent yield. The method is straight forward, economic, high-yielding and easy to perform in gram scale. The synthesised glycosylaled α-aminoalcohols may serve as interesting scaffold to develop new chemotherapeutic agents. © 2008 TrendsCarbo.com.
Trichloroisocyanuric Acid Mediated High-Yielding Synthesis of N -Acylbenzotriazoles under Mild Reaction Conditions
(Georg Thieme Verlag, 2019) Mala Singh; Anoop S. Singh; Nidhi Mishra; Anand K. Agrahari; Vinod K. Tiwari
N -Acylbenzotriazoles are achieved in good yields from the corresponding carboxylic acids by using only 0.35 equivalent of trichloroisocyanuric acid and 1.2 equivalents of PPh 3. The salient features of the developed reaction path include an economic, facile, base-free, and equally useful method in milligram to gram scale. © Georg Thieme Verlag Stuttgart New York.