71 results on '"Santosh L. Gaonkar"'
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2. In vitro and in silico insights into antimicrobial and anticancer activities of novel imidazo[2,1-b][1,3,4]thiadiazoles
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Deepika Dwarakanath, Yogeesha N. Nayak, Ananda Kulal, Samyak Pandey, K Sreedhara Ranganath Pai, and Santosh L. Gaonkar
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Medicine ,Science - Abstract
Abstract This study explores the design, synthesis, and evaluation of a novel series of isobenzofuran-based imidazo[2,1-b][1,3,4]thiadiazole derivatives, targeting their antimicrobial and anticancer properties. These compounds integrate the pharmacologically significant 1,3,4-thiadiazole and imidazole moieties, which are known for their potential in drug development, although imidazo[2,1-b][1,3,4]thiadiazole-based drugs are not yet available on the market. Therefore, the aim of this study is to develop novel derivatives that could serve as promising candidates for future therapeutic applications. The derivatives were synthesized in two steps and thoroughly characterized using IR, 1H NMR, 13C NMR, and mass spectrometry. All the derivatives had shown fairly good antimicrobial activity against four microorganisms (Escherichia coli, Staphylococcus aureus, Mycobacterium smegmatis and Candida albicans) with minimum inhibition concentration’s ranging from 0.14 to 0.59 mM. The anticancer activity of the compounds against MCF-7 cell lines showed promising activity, where three derivatives, 3a, 3c and 3d exhibited better inhibition than the standard, cisplatin. The highest anticancer activity was shown by the derivative 3c with an IC50 value of 35.81 μM. Molecular docking was studied to determine the docking poses and binding interaction of the derivatives with the protein bearing PDB: 5BNS and 3ZNR; ADME properties of the derivatives are also inferred which gives insights into the bioavailability. The molecular dynamics simulation of the derivative 3c with HDAC7 protien (PDB: 3ZNR) was evalauted to determine the stability of the interaction between the protein and the ligand. more...
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- 2024
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Catalog
3. Harnessing Nature’s Toolbox: Naturally Derived Bioactive Compounds in Nanotechnology Enhanced Formulations
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Chetana Sanjai, Santosh L. Gaonkar, and Sushruta S. Hakkimane
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Chemistry ,QD1-999 - Published
- 2024
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4. Development of Novel Indole and Coumarin Derivatives as Antibacterial Agents That Target Histidine Kinase in S. aureus
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Lisha K. Poonacha, Rashmi Ramesh, Akshay Ravish, Arunkumar Mohan, Pradeep M. Uppar, Prashant K. Metri, Nanjunda Swamy Shivananju, Santosh L. Gaonkar, Shubha Gopal, Alexey Yu Sukhorukov, Vijay Pandey, Priya Babu Shubha, and Basappa Basappa more...
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indole ,coumarin ,Suzuki coupling ,histidine kinase ,AutoDock ,Microbiology ,QR1-502 - Abstract
Heterocyclic compounds can specifically regulate bacterial development by targeting specific bacterial enzymes and metabolic pathways. The ESKAPE pathogens are multidrug-resistant and cause nosocomial infections, which is one of the greatest challenges in clinical practice. The search for novel agents to combat resistant bacteria has become one of the most important areas of antibacterial research today. Heterocyclic compounds offer a valuable strategy in the fight against resistance as they can be designed to interact with bacterial targets that are less prone to developing resistance mechanisms. Bacterial histidine kinases (HKs), which are a component of two-component bacterial systems, are a promising target for new antibacterial compounds. We have designed and synthesized novel indole derivatives as antibacterial agents. Among the series, indole-coumarin (4b) and bisindole (4e) have shown the best inhibitory activity against S. aureus. Further, in silico docking studies show that compounds 4b and 4e could target histidine kinases in bacteria. more...
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- 2023
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5. New benzisoxazole derivative: A potential corrosion inhibitor for mild steel in 0.5 M hydrochloric acid medium -insights from electrochemical and density functional theory studies
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Preethi Kumari P, Anusha G, J.N Cheerlin Mishma, Rajeev K. Sinha, Aishwarya S. Suvarna, and Santosh L. Gaonkar
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Benzisoxazole derivative ,corrosion ,DFT ,Adsorption ,Electrochemical measurement ,Science (General) ,Q1-390 ,Social sciences (General) ,H1-99 - Abstract
6-fluoro-3-(4-piperidinyl)-1,2-benzisoxazole. HCl (FPBH), a substituted benzisoxazole derivative, was prepared from isonipecotic acid and characterized using various spectroscopic techniques. Using electrochemical examinations such as potentiodynamic polarisation (PDP) and electrochemical impedance spectroscopic (EIS) technique, the corrosion mitigation capabilities of this compound for mild steel (MS) in 0.5 M HCl medium were investigated. Theoretical studies were performed using quantum chemical calculations and density functional theory (DFT). PDP results exhibited the mixed-type behavior of FPBH and showed a maximum efficiency of 94.5 % at 1 × 10−3 M. The development of a protective adsorbed layer of FPBH decreases the corrosion current density (icorr) and corrosion rate (CR). The EIS technique revealed that the rise in the charge transfer resistance (Rct) values and reduction in the thickness of the double-layer capacitance (Cdl) reflected the drop in corrosion rate. The adsorption of FPBH took place through physisorption by conforming Langmuir's isotherm. The DFT method was performed on the optimized structure of FPBH to get additional evidence on the action mode of FPBH with the metal surface. more...
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- 2023
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6. Development of Piperazine- and Oxazine-Linked Pyrimidines as p65 Subunit Binders of NF–κB in Human Breast Cancer Cells
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Akshay Ravish, Bhanuprakash C. Narasimhachar, Zhang Xi, Divakar Vishwanath, Arunkumar Mohan, Santosh L. Gaonkar, Paduvalahippe Gowdegowda Chandrashekara, Kwang Seok Ahn, Vijay Pandey, Peter E. Lobie, and Basappa Basappa more...
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oxazines ,piperazines ,pyrimidines ,NF–κB ,Alamar Blue assay ,molecular docking ,Biology (General) ,QH301-705.5 - Abstract
Nuclear factor kappa B (NF–κB) is a potential therapeutic target in breast cancer. In the current study, a new class of oxazine– and piperazine–linked pyrimidines was developed as inhibitors of NF–κB, overcoming the complexity of the oxazine structure found in nature and enabling synthesis under laboratory conditions. Among the series of synthesized and tested oxazine–pyrimidine and piperazine–pyrimidine derivatives, compounds 3a and 5b inhibited breast cancer cell (MCF–7) viability with an IC50 value of 9.17 and 6.29 µM, respectively. In silico docking studies showed that the pyrimidine ring of 3a and the 4–methoxybenzyl thiol group of 5b could strongly bind the p65 subunit of NF–κB, with the binding energies −9.32 and −7.32 kcal mol−1. Furthermore, compounds 3a and 5b inhibited NF–κB in MCF–7 breast cancer cells. In conclusion, we herein report newer structures that target NF–κB in BC cells. more...
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- 2023
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7. Electrochemical Synthesis of New Isoxazoles and Triazoles Tethered with Thiouracil Base as Inhibitors of Histone Deacetylases in Human Breast Cancer Cells
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Divakar Vishwanath, Zhang Xi, Akshay Ravish, Arunkumar Mohan, Shreeja Basappa, Niranjan Pattehalli Krishnamurthy, Santosh L. Gaonkar, Vijay Pandey, Peter E. Lobie, and Basappa Basappa
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breast cancer ,HDAC ,triazole ,isoxazole ,thiouracil ,drug discovery ,Organic chemistry ,QD241-441 - Abstract
Histone deacetylases (HDACs) are an attractive drug target for the treatment of human breast cancer (BC), and therefore, HDAC inhibitors (HDACis) are being used in preclinical and clinical studies. The need to understand the scope of the mode of action of HDACis, as well as the report of the co-crystal structure of HDAC6/SS-208 at the catalytic site, provoked us to develop an isoxazole-based lead structure called 4-(2-(((1-(3,4-dichlorophenyl)-1H-1,2,3-triazol-4-yl)methyl)thio) pyrimidin-4-yl) morpholine (5h) and 1-(2-(((3-(p-tolyl) isoxazol-5-yl)methyl)thio) pyrimidin-4-yl) piperidin-4-one (6l) that targets HDACs in human BC cells. We found that the compound 5h or 6l could inhibit the proliferation of BC cells with an IC50 value of 8.754 and 11.71 µM, respectively. Our detailed in silico analysis showed that 5h or 6l compounds could target HDAC in MCF-7 cells. In conclusion, we identified a new structure bearing triazole, isoxazole, and thiouracil moiety, which could target HDAC in MCF-7 cells and serve as a base to make new drugs against cancer. more...
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- 2023
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8. Chloramine-T (N-chloro-p-toluenesulfonamide sodium salt), a versatile reagent in organic synthesis and analytical chemistry: An up to date review
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Yogeesha N. Nayak, Santosh L. Gaonkar, Ebraheem Abdu Musad Saleh, Abdullah Mohammed A.L. Dawsari, Harshitha, Kakul Husain, and Ismail Hassan
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Chloramine-T ,Oxidant ,Cycloaddition ,Aziridination ,Halogenation ,Heterocycle synthesis ,Chemistry ,QD1-999 - Abstract
Chloramine-T (CAT), the sodium salt of N-chloro-p-toluenesulfonamide, is a low-cost mild oxidizing agent with a wide range of uses. Most importantly, it can be used in acidic, neutral, and basic conditions. As a result, it’s been widely used in chemistry, particularly in organic synthesis and analytical chemistry. Chloramine-T acts as a source of halonium cation and nitrogen anion and thus acts as base and nucleophile. It reacts with a wide range of functional groups and carries different molecular transformations. This paper thoroughly summarises and highlights the synthetic and analytical effectiveness of CAT. This study focuses on current developments as well as some older techniques in which CAT has been employed as an oxidizing agent. This review article stretches a comprehensive profile of the CAT reagent in organic synthesis and analytical chemistry, which will be very useful for further research exploration in this field. more...
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- 2022
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9. 1,3,4-Oxadiazole-containing hybrids as potential anticancer agents: Recent developments, mechanism of action and structure-activity relationships
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Swarnagowri Nayak, Santosh L. Gaonkar, Ebraheem Abdu Musad, and Abdullah Mohammed AL Dawsar
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1,3,4-Oxadiazoles ,Hybrid molecules ,Anticancer activity ,Structure–activity relationships ,Mechanisms of action ,Chemistry ,QD1-999 - Abstract
Chemotherapy is an important therapeutic approach for the treatment of cancer. Currently, many anticancer drugs are available in the market that plays an important role in cancer treatment, but concerns such as, drug resistance and side effects create an urgent need for the development of new anti-tumor drugs with high potency and less side effects. Heterocycles are of great interest due to their fascinating anticancer activity. Among them, 1,3,4-oxadiazoles showed attracting anti-tumor activity and its derivatives are under clinical trials for the treatment of cancer. Hybridization of 1,3,4-oxadiazole moiety with other heterocyclic pharmacophoresis a promising approach to overcome various disadvantages of current anticancer drugs such as drug resistance, toxicity, and other side effects. Thus, 1,3,4-oxadiazole-heterocycle hybrids occupy a significant position in the discovery of anti-tumor drugs. Among the reported oxadiazole-based hybrids reviewed here, compounds 45i, 59j, and 62x showed the highest anticancer activity with IC50 values in the nanomolar range. This review summarizes the recent developments in the anticancer potential, structure–activity relationships, and mechanisms of actions of 1,3,4-oxadiazole-heterocycle hybrids. more...
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- 2021
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10. SYNTHESIS OF THIOESTERS AND THIOAMIDES USING POTASSIUM THIOCYANATE UNDER MICROWAVE IRRADIATION
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Deepika D., Santosh L. Gaonkar, and Nitin kumar S. Shetty
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General Energy ,General Chemical Engineering ,General Chemistry ,General Pharmacology, Toxicology and Pharmaceutics ,Biochemistry - Abstract
Microwave-assisted synthesis provides more time for chemists to expand their creativeness, develop new processes and new theories. Recent developments in chemical sciences created microwave energy a new proficient way of heating the reaction.1 Microwave energy bids abundant benefits for the execution of synthesis comprising enhanced reaction rates, improved yield and cleaner chemistries. Using this technique, reactions can be performed in minutes, instead of spending hours to days in a conventional manner. The difficulty accompanying effluent disposal is overcome by executing the reactions without the use of solvent under microwave irradiation. Microwave irradiation reaction under solvent-free conditions, mineralsupported catalyzed reactions etc. provides better chemical methods with higher reaction rate, improved yield, good selectivity.2 Chemical reactions that took an hour to days the completion can be performed in minutes. The microwave region is positioned between IR and radio waves in the electromagnetic spectrum. The wavelength of microwave radiation is 1 mm-1 m with the frequencies 0.3-300 GHz. Dielectric heating in microwaves utilizes the capability of various solids and liquids to convert electromagnetic energy into heat to progress the reactions. The microwave technique has been applied in various research technologies like drug release/targeting,3 polymer technology,4 waste treatment,5 ceramics,6 alkane decomposition,7 etc. Consequently, microwave technology entertains as a potential method in green chemistry.8 This technology unlocks new openings as a new heating technique which is very difficult by the regular heating method.9 Organosulfur compounds are versatile intermediates in synthetic chemistry, possess many imperative biological properties.10 The applications and choice of organo-sulfur compounds have augmented enormously as sulfur comprising groups continue to function as an imperative supplementary function in synthetic arrangements.11 Thiocarbonyl comprising compounds are useful synthetic intermediates, that find numerous uses in the preparation of natural products.12 Although various reagents are accessible for the preparation of thioesters or thioamides, there are some drawbacks. Some of the important reagents used for thionation comprises lawessons reagent,13 H2S,14 phosphorous pentasulfide,15 hexamethyldisilathine,16 R3OBF4/NaSH,17 R2PSX,18 (Et2Al)2S,19 bis(tricyclcohexylstannyl) sulfide/BCl3, 20 thiourea,21 etc. Many of these reagents involve high temperatures, prolonged reaction times, or harsh conditions for reaction execution and frequently require problematic column chromatography to separate and remove the unwanted products. Batool A. et al. described a green procedure for the synthesis of thieranes from oxiranes by using ammonium thiocyanate.22 Encouraged by this, and in persistence to our work on the development of biologically active heterocycles,23-26 we thought of using simple and commercially available reagent potassium thiocyanate for the transformation of esters into thioesters by making use of microwave irradiation. more...
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- 2022
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11. A NEW MICROWAVE-ASSISTED METHOD FOR THE SYNTHESIS OF 2-SUBSTITUTED-THIAZOL-4(5H)-ONE VIA HANTZSCH CONDENSATION
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Swarnagowri Nayak and Santosh L Gaonkar
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General Energy ,General Chemical Engineering ,General Chemistry ,General Pharmacology, Toxicology and Pharmaceutics ,Biochemistry - Abstract
A new microwave-assisted method is developed for the synthesis of 2-substituted-thiazol-4(5H)-ones via Hantzsch condensation by a simple experimental protocol without using any catalyst. The products were isolated in excellent yield without any purification. Synthesized compounds were characterized by applying FTIR, 1H NMR, 13C NMR, and mass spectral studies and a plausible mechanism is proposed for the formation of the product. The method is versatile for the preparation of a new class of 2-substituted-thiazol-4(5H)-ones. more...
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- 2022
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12. Favipiravir (6‐Fluoro‐3‐hydroxy‐2‐pyrazinecarboxamide) a Broad Spectrum Inhibitor of Viral RNA Polymerase in COVID‐19 Treatment
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Sushruta S. Hakkimane, Deepika D, and Santosh L. Gaonkar
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Drug ,6-fluoro-3-hydroxy-2-pyrazinecarboxamide ,Coronavirus disease 2019 (COVID-19) ,biology ,business.industry ,medicine.drug_class ,media_common.quotation_subject ,General Chemistry ,Favipiravir ,Symptomatic relief ,Virology ,Pandemic ,biology.protein ,Medicine ,Antiviral drug ,business ,Polymerase ,media_common - Abstract
A pandemic disease, COVID-19, affecting over 253 million and 5.1 million deaths reported as on November 2021 from across the globe. The worst hit pandemic since a century. Scientists around the world are working towards the development of drugs for its treatment. Several existing antiviral medications have been tried for the same. Among these, Favipiravir, a broad-spectrum antiviral drug originally developed to treat influenza, shows noted activity against an ample range of RNA viruses. It is an oral antiviral drug with good bioavailability found to be effective in the treatment of COVID-19. This drug has acquired FDA manifestation for drug-resistant Influenza as it has confirmed its safety profile. There has been growing evidence that it helps in early viral clearance and speedy symptomatic relief against COVID-19. This review attempts to provide synthetic methods of favipiravir, mechanism of action and its importance in the treatment of COVID-19 and other viruses. more...
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- 2021
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13. Coinage Metal N‐ Heterocyclic Carbene Complexes: Recent Synthetic Strategies and Medicinal Applications
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Santosh L. Gaonkar and Swarnagowri Nayak
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Cell Survival ,Antineoplastic Agents ,Gram-Positive Bacteria ,01 natural sciences ,Biochemistry ,Metal ,Structure-Activity Relationship ,chemistry.chemical_compound ,Anti-Infective Agents ,Coordination Complexes ,Heterocyclic Compounds ,Gram-Negative Bacteria ,Drug Discovery ,Humans ,General Pharmacology, Toxicology and Pharmaceutics ,Pharmacology ,010405 organic chemistry ,Organic Chemistry ,Combinatorial chemistry ,Anticancer drug ,0104 chemical sciences ,010404 medicinal & biomolecular chemistry ,chemistry ,visual_art ,visual_art.visual_art_medium ,Molecular Medicine ,Methane ,Carbene - Abstract
New weapons are constantly needed in the fight against cancer. The discovery of cisplatin as an anticancer drug prompted the search for new metal complexes. The successful history of cisplatin motivated chemists to develop a plethora of metal-based molecules. Among them, metal-N-heterocyclic carbene (NHC) complexes have gained significant attention because of their suitable qualities for efficient drug design. The enhanced applications of coinage metal-NHC complexes have encouraged a gradually increasing number of studies in the fields of medicinal chemistry that benefit from the fascinating chemical properties of these complexes. This review aims to present recent developments in synthetic strategies and medicinal applications of copper, silver and gold complexes supported by NHC ligands. more...
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- 2021
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14. Advances in Synthetic Strategies and Medicinal Importance of Benzofurans: A Review
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Deepika Dwarakanath and Santosh L. Gaonkar
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Organic Chemistry - Published
- 2022
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15. Synthesis, Molecular Docking and Evaluation of Library of 3-Mercapto-1,2,4-Triazole Derivatives as Antimicrobial Agents
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Swarnagowri Nayak, Santosh L. Gaonkar, Sushruta S. Hakkimane, Swapna B, and Nitinkumar S. Shetty
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General Chemistry - Abstract
Due to the increasing microbial resistance to antibacterial and antifungal drugs, the development of new antimicrobial agents is an urgent priority. In search of newer antimicrobial agents, a series of 4,5-disubstituted-3-mercapto-1,2,4-triazole derivatives were synthesized from aromatic acids and substituted isothiocyanates. The in silico study was performed to study the binding interactions of the synthesized compounds with the active pocket of CYP51. Among the synthesized 3-mercapto-triazole derivatives, compounds 6r, 6s and 6u exhibited promising antimicrobial activity comparable to standard drugs. The results suggested that the structural modification to 3-mercapto-1,2,4-triazole derivatives could lead to promising antimicrobial scaffolds. more...
- Published
- 2021
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16. Zeolite Catalyzed Friedel-Crafts Reactions: A Review
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Y. F. Nadaf, Nitinkumar S. Shetty, Swarnagowri Nayak, Santosh L. Gaonkar, and Yogeesha N. Nayak
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010405 organic chemistry ,Chemistry ,Organic Chemistry ,Aromatic ketones ,Alkylation ,010402 general chemistry ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Catalysis ,Acylation ,Organic chemistry ,Zeolite ,Selectivity ,Friedel–Crafts reaction - Abstract
Friedel-Crafts reaction is one of the most useful synthetic tools in organic chemistry, mainly in the synthesis of aromatic ketones. The active catalysts for this reaction are modified zeolites and are preferable catalysts when shape selectivity affects the formation of the expected product. In this review, our aim is to corroborate recent literature available on zeolite catalyzed Friedel-Crafts alkylation and acylation reaction. more...
- Published
- 2020
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17. Inhibitory effect of a new isoniazid derivative as an effective inhibitor for mild steel corrosion in 1.0 M HCl: combined experimental and computational study
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I M Chung, H. Oudda, Rachid Salghi, Maryam Chafiq, Ismat H. Ali, Hassane Lgaz, Santosh L. Gaonkar, K S Bhat, and Abdelkarim Chaouiki
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Materials science ,010405 organic chemistry ,Langmuir adsorption model ,Context (language use) ,General Chemistry ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,Cathodic protection ,Corrosion ,chemistry.chemical_compound ,Corrosion inhibitor ,symbols.namesake ,Adsorption ,chemistry ,symbols ,Derivative (chemistry) ,Nuclear chemistry - Abstract
Controlling corrosion of metals such as mild steel (MS), which is extensively employed in various industrial fields, is a topic of great interest for researchers and scientists. At the same time, designing highly effective and environmentally friendly corrosion inhibitors is most desired yet still challenging. In this context, this study focuses on the use of a new corrosion inhibitor namely (E)-N′-(4-(2-(methyl(pyridin-2-yl)amino)ethoxy)benzylidene) isonicotinohydrazide (INH) as efficient, sustainable inhibitors for MS corrosion in acidic medium (1.0 M HCl). Different chemical, electrochemical and theoretical approaches were used to study and give new insights into the mechanism of corrosion protection of MS by the synthesized isonicotinohydrazide derivative. Experimental results disclosed that this compound could effectively control and reduce the corrosion of MS through physicochemical adsorption, which follows the Langmuir isotherm model. Potentiodynamic polarization technique (PDP) showed that the studied inhibitor affects both anodic and cathodic reactions; thus, it demonstrated that it is a mixed-type inhibitor. Moreover, surface characterization of metal by scanning electron microscope confirms that our inhibitor is subject to strong adsorption over the iron surface. Besides experimental techniques, theoretical approaches like DFT calculations, molecular dynamics simulation and radial distribution function were used to give precise information about the mechanism of corrosion inhibition and unveiled factors controlling the performance of the investigated inhibitor. more...
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- 2020
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18. Synthesis, Molecular Docking and Evaluation of 1,3,4‐Oxadiazole‐Isobenzofuran Hybrids as Antimicrobial and Anticancer Agents
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Swarnagowri Nayak, Santosh L. Gaonkar, Druti Hazra, Kiran Chawla, Gangadhar Hari, K. S. R. Pai, Bharath Raja Guru, and Sushruta S. Hakimane
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Oxadiazoles ,Staphylococcus aureus ,Molecular Structure ,Antineoplastic Agents ,Bioengineering ,General Chemistry ,General Medicine ,Biochemistry ,Anti-Bacterial Agents ,Molecular Docking Simulation ,Structure-Activity Relationship ,Anti-Infective Agents ,Spectroscopy, Fourier Transform Infrared ,Escherichia coli ,Humans ,Molecular Medicine ,Drug Screening Assays, Antitumor ,Molecular Biology ,Cell Proliferation - Abstract
In drug discovery, the hybridization of bioactive pharmacophores is a powerful tool for targeting enzymes involved in cancer and microbial cell growth. A combination of 1,3,4-oxadiazole and isobenzofuran may improve the antitumor and antimicrobial properties of the hybrid molecules. A series of hybrid molecules having 1,3,4-oxadiazole and isobenzofuran were synthesized and structural characterization was done by FT-IR more...
- Published
- 2022
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19. A comprehensive review on Covid-19 Omicron (B.1.1.529) variant
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R Manjunath, Santosh L. Gaonkar, Ebraheem Abdu Musad Saleh, and Kakul Husain
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General Agricultural and Biological Sciences - Abstract
The world has been combating different variants of SARS-COV-19 since its first outbreak in Wuhan city. SARS-COV-19 is caused by the coronavirus. The corona virus mutates and becomes more transmissible than earlier variants as the day passes. Till 24 November 2021, SARS-COV-19 has four variants Alpha, Beta, Gamma, and Delta, respectively. Among them, the delta variant caused severe havoc across the world. South Africa registered a new variant with the World Health Organization (WHO) on 24 November 2021, which is much more transmissible than previous variants. The WHO classified it as a variant of concern (VOC) on 26 November 2021 and called it the Greek letter Omicron (B.1.1.529), the fifteenth letter in the alphabet. Here a serious attempt was made to comprehend the omicron variant's origin, nomenclature, characteristics, mutations, the difference between delta and omicron variant, epidemiology, transmission, clinical features, impact on immunity, immune evasion, vaccines efficacy, etc. more...
- Published
- 2022
20. 1,3,4-Oxadiazole-containing hybrids as potential anticancer agents: Recent developments, mechanism of action and structure-activity relationships
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Santosh L. Gaonkar, Abdullah Mohammed Al Dawsar, Swarnagowri Nayak, and Ebraheem Abdu Musad
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Chemistry ,Cancer ,Oxadiazole ,General Chemistry ,Drug resistance ,Pharmacology ,medicine.disease ,Hybrid molecules ,Anticancer activity ,Cancer treatment ,chemistry.chemical_compound ,Structure–activity relationships ,Mechanism of action ,Mechanisms of action ,Ic50 values ,medicine ,medicine.symptom ,QD1-999 ,1,3,4-Oxadiazoles - Abstract
Chemotherapy is an important therapeutic approach for the treatment of cancer. Currently, many anticancer drugs are available in the market that plays an important role in cancer treatment, but concerns such as, drug resistance and side effects create an urgent need for the development of new anti-tumor drugs with high potency and less side effects. Heterocycles are of great interest due to their fascinating anticancer activity. Among them, 1,3,4-oxadiazoles showed attracting anti-tumor activity and its derivatives are under clinical trials for the treatment of cancer. Hybridization of 1,3,4-oxadiazole moiety with other heterocyclic pharmacophoresis a promising approach to overcome various disadvantages of current anticancer drugs such as drug resistance, toxicity, and other side effects. Thus, 1,3,4-oxadiazole-heterocycle hybrids occupy a significant position in the discovery of anti-tumor drugs. Among the reported oxadiazole-based hybrids reviewed here, compounds 45i, 59j, and 62x showed the highest anticancer activity with IC50 values in the nanomolar range. This review summarizes the recent developments in the anticancer potential, structure–activity relationships, and mechanisms of actions of 1,3,4-oxadiazole-heterocycle hybrids. more...
- Published
- 2021
21. SYNTHESIS, ANTIOXIDANT AND ANTICANCER ACTIVITY OF NEW QUINOLINE-[1, 2, 4]-TRIAZOLE HYBRIDS
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Hemanth Hegde, Nitinkumar S Shetty, Santosh L. Gaonkar, and Naveen P Badiger
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Antioxidant ,Chemistry ,General Chemical Engineering ,medicine.medical_treatment ,Quinoline ,Triazole ,1,2,4-Triazole ,General Chemistry ,Hydrazide ,Biochemistry ,Combinatorial chemistry ,chemistry.chemical_compound ,General Energy ,13c nmr spectroscopy ,Isothiocyanate ,medicine ,Molecule ,General Pharmacology, Toxicology and Pharmaceutics - Abstract
A set of quinoline coupled triazole derivatives was synthesized using substituted quinoline hydrazide and isothiocyanate derivatives. The structures of the synthesized molecules were confirmed using spectral techniques like FTIR, 1H & 13C NMR spectroscopy. Novel triazole thione derivatives were subjected to anticancer and antioxidant activity. The studies revealed the moderate anticancer activity of the molecules but have shown potent antioxidant activity more...
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- 2020
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22. STABLE ISONIAZID DERIVATIVES: IN SILICO STUDIES, SYNTHESIS AND BIOLOGICAL ASSESSMENT AGAINST Mycobacterium tuberculosis IN LIQUID CULTURE
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Santosh L. Gaonkar, Bharath Raja Guru, Sushruta S. Hakkimane, U. N. Vignesh, B. R. Bharath, and Vishnu Prasad Shenoy
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biology ,Chemistry ,Liquid culture ,General Chemical Engineering ,In silico ,Isoniazid ,General Chemistry ,biology.organism_classification ,Biochemistry ,Microbiology ,Mycobacterium tuberculosis ,General Energy ,medicine ,General Pharmacology, Toxicology and Pharmaceutics ,medicine.drug - Published
- 2020
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23. Exploring deep insights into the interaction mechanism of a quinazoline derivative with mild steel in HCl: electrochemical, DFT, and molecular dynamic simulation studies
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Ismat H. Ali, H. Oudda, Santosh L. Gaonkar, Yasmina El Aoufir, K. Subrahmanya Bhat, Mohammad I. Khan, Saman Zehra, Hassane Lgaz, Rachid Salghi, Ill-Min Chung, and Abdelkarim Chaouiki
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Materials science ,Langmuir adsorption model ,030206 dentistry ,02 engineering and technology ,Surfaces and Interfaces ,General Chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,Surfaces, Coatings and Films ,Dielectric spectroscopy ,Corrosion ,03 medical and health sciences ,symbols.namesake ,Corrosion inhibitor ,chemistry.chemical_compound ,0302 clinical medicine ,Adsorption ,chemistry ,Mechanics of Materials ,Materials Chemistry ,symbols ,Physical chemistry ,Density functional theory ,0210 nano-technology ,Polarization (electrochemistry) - Abstract
A novel quinazoline derivative, 3-cyclopropyl-3,4-dihydroquinoline- 2(1H)-One (CPHQ), was successfully designed and synthesized. Then, its corrosion inhibition behavior on carbon steel (CS) surface in 1.0M HCl at different temperatures was investigated using chemical, electrochemical and theoretical techniques. The experiments confirmed that the studied inhibitor shows inhibition efficiency as high as 95% even at very low concentration of 5�10�3 M. To ascertain the nature of adsorption of CPHQ molecules on CS surface, Langmuir adsorption isotherm model was best fitted. From potentiodynamic polarization (PDP) calculations, it was concluded that the CPHQ acted as a mixed type corrosion inhibitor. Electrochemical impedance spectroscopy (EIS) studies revealed that increase in CPHQ concentration, resulted in an increase in the polarization resistance with a simultaneous decrease in the doublelayer capacitance values. PDP tests were also performed to understand the corrosion behavior of CS as a function of temperature without and with varying concentrations of CPHQ, at temperatures 303, 313, 323, and 333 K. It can be concluded that the corrosion inhibition effect was dependent on the concentration of the inhibitor and the solution temperature. In order to understand the basic insights of the action mode of CPHQ molecules, Density Functional Theory (DFT) method, and Molecular Dynamic (MD) simulations were also employed on the optimized structure of CPHQ. more...
- Published
- 2019
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24. An Efficient and Industrially Scalable Total Synthesis of Anti-Alzheimer Drug Donepezil
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Santosh L. Gaonkar
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Drug ,Anti alzheimer ,business.industry ,media_common.quotation_subject ,Total synthesis ,Disease ,Pharmacology ,medicine.disease ,Donepezil Hydrochloride ,mental disorders ,medicine ,Dementia ,business ,Donepezil ,Butyrylcholinesterase ,media_common ,medicine.drug - Abstract
Alzheimer's disease, a chronic neurodegenerative disease which usually starts slowly and worsens over time. Alzheimer's disease individuals exhibit retrogression in mental health functions rendering them incapacitated and unable to perform normal daily activities. Elderly persons are the ones commonly afflicted with this disease. However, evidence shows that it can also afflict even individuals as young as 40 years of age. It is a kind of dementia has no cure and in time leads to death. Donepezil is a well-known drug used to treat Alzheimer's disease. Donepezil hydrochloride is the second drug approved by the United States food and drug administration (FDA) for the treatment of mild to moderate alzheimer's diseases (AD). It is a new class of acetyl cholinesterase (AChE) inhibitor having an N-benzylpiperidine and an indanone moiety that shows longer and more selective action. Donepezil HCl, a piperidine derivative, is a highly selective inhibitor of the enzyme AChE that is chemically unique from other AChE inhibitors. In vitro and preclinical studies have demonstrated that Donepezil is much more selective for AChE in the brain than for butyrylcholinesterase (BuChE) in the periphery. Various methods for the synthesis of donepezil and an improved, industrially scalable total synthesis are presented in this chapter. Physical properties and pharmacology are also included. more...
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- 2021
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25. New Benzohydrazide Derivative as Corrosion Inhibitor for Carbon Steel in a 1.0 M HCl Solution: Electrochemical, DFT and Monte Carlo Simulation Studies
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Santosh L. Gaonkar, Subrahmanya K Bhat, K. Toumiat, Shehdeh Jodeh, Rachid Salghi, Abdelkarim Chaouiki, Hassane Lgaz, and H. Oudda
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Materials science ,Carbon steel ,Double-layer capacitance ,engineering.material ,HCl ,010402 general chemistry ,DFT ,01 natural sciences ,Monte Carlo simulations ,Corrosion ,symbols.namesake ,Corrosion inhibitor ,chemistry.chemical_compound ,Adsorption ,Electrochemistry ,Polarization (electrochemistry) ,010405 organic chemistry ,carbon steel ,Langmuir adsorption model ,corrosion inhibition ,0104 chemical sciences ,Dielectric spectroscopy ,chemistry ,benzohydrazide derivative ,symbols ,engineering ,Physical chemistry - Abstract
The present study aimed to evaluate the inhibition effect of an organic compound, namely, (E -N'-(2-hydroxybenzylidene) isonicotinohydrazide (BIH), for carbon steel corrosion in a 1.0 M HCl solution, by using weight loss (WL), potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). Results show that BIH is a good inhibitor, and the percentage of inhibition efficiency increases on its higher concentrations. The maximum inhibition efficiency of 94% was obtained at 5×10-3 M. Polarization studies revealed that the BIH compound acts as a mixed type inhibitor. EIS showed that increasing the concentration of the inhibitor led to an increase in the charge transfer resistance and a decrease in the double layer capacitance. It was found that the adsorption of this compound obeyed the Langmuir adsorption isotherm. The associated activation energies and thermodynamic parameters of the adsorption process were evaluated and discussed. The temperature effect was studied in the range from 303 to 333 K. In addition, quantum chemical calculations based on the density function theory (DFT) and Monte Carlo simulations were done to support the experimental results. more...
- Published
- 2019
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26. A Review on Current Synthetic Strategies of Oxazines
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Swarnagouri Nayak, Vignesh U Nagaraj, and Santosh L. Gaonkar
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chemistry.chemical_classification ,chemistry.chemical_compound ,010405 organic chemistry ,Chemistry ,Biological property ,Organic Chemistry ,Oxazines ,010402 general chemistry ,Bifunctional ,01 natural sciences ,Combinatorial chemistry ,0104 chemical sciences - Abstract
In the past three decades, the heterocyclic oxazine cores have been intensely concerned. Oxazine derivatives are promising vital heterocyclic motifs. They are eminent for their synthetic potential and extensive biological properties. Oxazines are versatile intermediates for the synthesis of a variety of heterocycles and bifunctional compounds. Researchers have reported several synthetic approaches for the preparation of oxazines. This review emphasises the recent approaches for the synthesis of oxazine derivatives. more...
- Published
- 2018
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27. Understanding corrosion inhibition of mild steel in acid medium by new benzonitriles: Insights from experimental and computational studies
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H. Oudda, K.S. Bhat, Ill-Min Chung, Ismat H. Ali, Santosh L. Gaonkar, Rachid Salghi, Mohammad I. Khan, Abdelkarim Chaouiki, and Hassane Lgaz
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Langmuir ,Materials science ,Carbon steel ,02 engineering and technology ,engineering.material ,010402 general chemistry ,Electrochemistry ,01 natural sciences ,Corrosion ,chemistry.chemical_compound ,Adsorption ,Materials Chemistry ,Physical and Theoretical Chemistry ,Polarization (electrochemistry) ,Spectroscopy ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Dielectric spectroscopy ,Benzonitrile ,chemistry ,engineering ,0210 nano-technology ,Nuclear chemistry - Abstract
Two benzonitrile derivatives, namely 4-(isopentylamino)-3-nitrobenzonitrile (PANB) and 3-amino-4-(isopentylamino)benzonitrile(APAB) have been synthesized and evaluated as corrosion inhibitors for mild steel (MS) in 1 M HCl solution at 303 K by gravimetric, potentiodynamic polarization (PDP) curves, and electrochemical impedance spectroscopy (EIS) methods, as well as Density Functional Theory (DFT) and molecular dynamics (MD) simulations. The results suggest that tested compounds are excellent corrosion inhibitors for mild steel with PANB showing superior performance. Polarization measurements revealed that PANB and APAB behaved as mixed type inhibitors. The polarization resistance, according to EIS studies, found to be dependent on the inhibitor's concentration. The adsorption of PANB and APAB on mild steel surface obeyed Langmuir's adsorption isotherm. On the one hand, DFT and MD simulations are being used to explain the effect of the molecular structure on the corrosion inhibition efficiency and on the other hand to simulate the adsorption of benzonitrile derivatives on mild steel surface. The protection of carbon steel in 1 M HCl was confirmed by using scanning electron microscope (SEM) and Atomic Force Microscopy (AFM). Electrochemical, DFT and MD simulations results are in good agreement. more...
- Published
- 2018
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28. Synthesis, Crystal Structure, Biological Evaluation, DFT Calculations and Third Order Nonlinear Optical Studies of Pyrazolines
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Rajeev K. Sinha, Swarnagowri Nayak, Vinay Parol, Gangadhar Hari, K.S.R. Pai, Santosh L. Gaonkar, Neratur Krishnappagowda Lokanath, and Sri Ram G. Naraharisetty
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010405 organic chemistry ,Chemistry ,Organic Chemistry ,Protein Data Bank (RCSB PDB) ,Hyperpolarizability ,Crystal structure ,010402 general chemistry ,01 natural sciences ,0104 chemical sciences ,Analytical Chemistry ,Inorganic Chemistry ,Lipinski's rule of five ,Physical chemistry ,Molecule ,Density functional theory ,Fourier transform infrared spectroscopy ,Absorption (chemistry) ,Spectroscopy - Abstract
Novel pyrazoline derivatives were synthesized and characterized by FTIR, NMR, UV-visible, and mass spectral studies. All the synthesized compounds 6a-f were screened for anticancer activity against MCF-7 and HCT 116 cell lines via SRB assay. Among the synthesized pyrazolines 6b and 6f showed appreciable anticancer activity. The molecular docking study was done with two proteins (PDB No: 1M17 and 5ZTO) to study the binding interactions of the compounds with proteins. ADME study showed that the compounds exhibited drug-likeness properties, following Lipinski's rule of five. The molecular structure of compound 6b was studied using the single-crystal X-ray diffraction method. The structural, absorption and first static hyperpolarizability properties of the compound 6b were studied using density functional theory (DFT) calculations. The experimental data and calculated FTIR and UV-visible spectral data are in good agreement. The third order nonlinear optical properties were studied using open and closed aperture z-scan techniques. The compound 6b showed nonlinear absorption ( β ) of 1.94 × 10 − 11 m/W at intensity ( I 0 ) is 4.49 GW / c m 2 . Third order nonlinear susceptibility is of the order of 10−12 esu and this indicates the molecule has the potential to be used in nonlinear optical device applications. more...
- Published
- 2021
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29. Synthesis, characterization, DFT and photophysical studies of new class of 1,3,4-oxadiazole-isobenzofuran hybrids
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Prinston Melroy Lewis, Rajeev K. Sinha, Suresh D. Kulkarni, Santosh L. Gaonkar, and Swarnagowri Nayak
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Materials science ,Photoluminescence ,Isobenzofuran ,Biophysics ,Quantum yield ,Oxadiazole ,02 engineering and technology ,General Chemistry ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Biochemistry ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Physical chemistry ,Molecule ,Quantum efficiency ,Density functional theory ,0210 nano-technology ,Spectroscopy - Abstract
Oxadiazole-based molecules are a fascinating and continuously developing area of research. These compounds show motivating luminescent properties, emitting blue to green light with high quantum efficiency depending on the substituents attached to the oxadiazole ring. New 1,3,4-oxadiazole derivatives bearing isobenzofuran moiety were designed and synthesized and their optical properties were studied. All synthesized compounds were characterized using FTIR, NMR, and mass spectrometry. The UV–visible spectroscopy, photoluminescence spectroscopy, and quantum efficiency were determined at room temperature. The structural and absorption properties of the molecules were investigated using density functional theory (DFT) calculations. The orbital picture of all the excitations involved in these transitions were identified as π->π*. The experimental data and the DFT calculated FTIR and UV–visible spectral data are in good agreement. The fluorescence spectra of molecules show emission in the range from 343-393 nm and exhibit high quantum yield. more...
- Published
- 2021
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30. Synthesis and pharmacological properties of chalcones: a review
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Santosh L. Gaonkar and U. N. Vignesh
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Antifungal ,Chalcone ,010405 organic chemistry ,Chemistry ,medicine.drug_class ,Stereochemistry ,General Chemistry ,010402 general chemistry ,Antimicrobial ,01 natural sciences ,Combinatorial chemistry ,0104 chemical sciences ,chemistry.chemical_compound ,medicine - Abstract
Chalcones and their analogs have been an area of great interest in recent years. Numerous research papers have been published, and chalcones continue to show promise for new drug investigations. Researchers have explored new approaches for the synthesis of chalcone derivatives, which have revealed an array of pharmacological and biological effects. These chalcone derivatives have shown important antimicrobial, antifungal, anti-mycobacterial, antimalarial, antiviral, anti-inflammatory, antioxidant, antileishmanial anti-tumor, and anticancer properties. This review highlights the synthesis and pharmacological properties of chalcone derivatives. more...
- Published
- 2017
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31. Synthesis of Fused-Oxazines from Cyclic Ketoximes Via a-Nitrosoalkenes
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Santosh L. Gaonkar and K. M. Lokanatha Rai
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Green chemistry ,chemistry.chemical_classification ,010405 organic chemistry ,Supramolecular chemistry ,Oxazines ,General Chemistry ,Radiation chemistry ,010402 general chemistry ,01 natural sciences ,Biochemistry ,Medicinal chemistry ,0104 chemical sciences ,Coordination complex ,chemistry.chemical_compound ,chemistry ,FLUIDEX ,Drug Discovery ,Polymer chemistry ,Theoretical chemistry ,Environmental Chemistry ,Triethylamine - Abstract
Cyclic ketoximes having a a-methylene group on reaction with chloramine-T followed by treatment with triethylamine generate a-nitrosoalkenes via a-chloronitroso intermediates, which are further treated with alkenes to give fused-oxazines more...
- Published
- 2017
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32. Effect of Ocimum on Cervical Intraepithelial Neoplasia (CIN) Pre Cervical Cancer
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Y. F. Nadaf, Dinesh Bilehal, Ayushi Tripathi, Swarnagowri Nayak, and Santosh L. Gaonkar
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Drug ,Chemistry ,Biological property ,media_common.quotation_subject ,Isoniazid ,medicine ,Pharmaceutical Science ,Moiety ,bacterial infections and mycoses ,Combinatorial chemistry ,Reactive site ,medicine.drug ,media_common - Abstract
Isoniazid is the most important heterocyclic moiety in organic and medicinal chemistry due to the presence of reactive site in the molecule, which extends its application in various fields. Isoniazid is the most important first-line drug used in the treatment of tuberculosis. The interesting molecular design of isoniazid makes them apt moieties in drug design. In this review, our aim is to summarize recent synthetic strategies and pharmacological properties of isoniazid derivatives more...
- Published
- 2019
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33. Industrially Scalable Synthesis of Anti-alzheimer Drug Donepezil
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Nitinkumar S. Shetty, Y. F. Nadaf, Santosh L. Gaonkar, and Dinesh Bilehal
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Drug ,chemistry.chemical_compound ,Anti alzheimer ,Chemistry ,Hydrochloride ,media_common.quotation_subject ,medicine ,General Chemistry ,Pharmacology ,Donepezil ,medicine.drug ,media_common - Abstract
hydrochloride. The article also reported the X-ray studies of the 2-(1-benzylpiperidin-4-ylmethyliden -5,6-dimethoxyindan-1-one, an intermediate in the sy
- Published
- 2017
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34. Synthesis, Characterization and Single Crystal Studies of 3-cyclopropyl-3, 4-dihydroquinazolin-2(1H)-one
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F Nadaf, Santosh L. Gaonkar, Nitinkumar S. Shetty, Dinesh Bilehal, and V. ShyamKumar
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Green chemistry ,chemistry.chemical_classification ,Supramolecular chemistry ,General Chemistry ,Crystal structure ,Biochemistry ,Medicinal chemistry ,Coordination complex ,Crystallography ,chemistry ,Drug Discovery ,Theoretical chemistry ,Proton NMR ,Environmental Chemistry ,Single crystal ,Monoclinic crystal system - Abstract
The paper describes industrially scalable synthesis and single crystal studies of cyclopropyl-3, 4-dihydroquinazolin-2(1H)-one 4, a versatile intermediate in the synthesis of number of biologically active compounds. The target compound has been characterized by LC-MS, 1H NMR and IR. The crystal structure analysis shows that the title compound crystallizes in monoclinic class under the space group P 1 21/n 1 with cell parameters, a = 10.273(2) A, b = 8.3227(19) A, c = 11.623(3) A, β = 104.980(3)°, V = 960.0(4) A3 and Z=4. more...
- Published
- 2016
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35. An Aerobic Oxidative Coupling Approach for The Synthesis of N-Substituted 2-Aminobenzothiazole Derivatives using Iron Catalyst
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Nitinkumar S. Shetty, Santosh L. Gaonkar, Shailesha Kamath, and N. V. Anil Kumar
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Green chemistry ,chemistry.chemical_classification ,010405 organic chemistry ,Chemistry ,Supramolecular chemistry ,General Chemistry ,Food chemistry ,Radiation chemistry ,010402 general chemistry ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Coordination complex ,FLUIDEX ,Drug Discovery ,Theoretical chemistry ,Environmental Chemistry ,Organic chemistry ,Oxidative coupling of methane - Abstract
A facile and convenient method was developed for the formation of novel N substituted 2-aminobenzothiazoles via an iron-catalysed condensation of 2-aminobenzothizole with different amines. This method is applicable for a wide range of aliphatic, aromatic and heterocyclic amines furnishing moderate yields of the corresponding products and thus rendering the methodology as a highly eco-friendly, inexpensive alternative to the existing methods. more...
- Published
- 2016
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36. Anthelmintic and antibacterial screening of a new series of N-[4-(4-nitrophenoxy)phenyl]-4-(substituted)-1,3-thiazol-2-amines
- Author
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Santosh L. Gaonkar and Namratha Bhandari
- Subjects
010405 organic chemistry ,Stereochemistry ,Organic Chemistry ,Carbon-13 NMR ,010402 general chemistry ,01 natural sciences ,Biochemistry ,0104 chemical sciences ,Nitroscanate ,chemistry.chemical_compound ,chemistry ,Thiourea ,Anthelmintic drug ,medicine ,Proton NMR ,Anthelmintic ,Thiazole ,medicine.drug - Abstract
A series of N-[4-(4-nitrophenoxy)phenyl]-4-(substituted)-1,3-thiazol-2-amines was synthesized. Structural elucidation was accomplished by 1H NMR, 13C NMR, IR, and elemental analyses of synthesized compounds. The title compounds were derived from 4-(4-nitrophenoxy)phenyl thiourea, which is the key intermediate in the synthesis of nitroscanate, an anthelmintic drug. Among the synthesized compounds, N-[4-(4-nitrophenoxy)phenyl]-4-(4-fluorophenyl)-1,3-thiazol-2-amine and N-[4-(4-nitrophenoxy)phenyl]-4-(4-methoxyphenyl)-1,3-thiazol-2-amine exhibited potent anthelmintic and antibacterial activities. more...
- Published
- 2016
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37. Antimycobacterial susceptibility evaluation of rifampicin and isoniazid benz-hydrazone in biodegradable polymeric nanoparticles against
- Author
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Sushruta S, Hakkimane, Vishnu Prasad, Shenoy, Santosh L, Gaonkar, Indira, Bairy, and Bharath Raja, Guru
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Polymers ,Drug Compounding ,Proton Magnetic Resonance Spectroscopy ,Static Electricity ,Antitubercular Agents ,Biocompatible Materials ,Microbial Sensitivity Tests ,drug susceptibility ,Mice ,Drug Delivery Systems ,Polylactic Acid-Polyglycolic Acid Copolymer ,Isoniazid ,Animals ,Humans ,Surface Tension ,Tuberculosis ,heterocyclic compounds ,Lactic Acid ,Particle Size ,Chromatography, High Pressure Liquid ,Original Research ,Chromatography, Reverse-Phase ,isoniazid hydrazone ,Cell Death ,technology, industry, and agriculture ,Mycobacterium tuberculosis ,biochemical phenomena, metabolism, and nutrition ,respiratory system ,bacterial infections and mycoses ,Drug Liberation ,RAW 264.7 Cells ,rifampicin nanoparticles ,A549 Cells ,Nanoparticles ,Rifampin ,Polyglycolic Acid - Abstract
Introduction Tuberculosis (TB) is the single largest infectious disease which requires a prolonged treatment regime with multiple drugs. The present treatment for TB includes frequent administration of a combination of four drugs for a duration of 6 months. This leads to patient’s noncompliance, in addition to developing drug-resistant strains which makes treatment more difficult. The formulation of drugs with biodegradable polymeric nanoparticles (NPs) promises to overcome this problem. Materials and methods In this study, we focus on two important drugs used for TB treatment – rifampicin (RIF) and isoniazid (INH) – and report a detailed study of RIF-loaded poly lactic-co-glycolic acid (PLGA) NPs and INH modified as INH benz-hydrazone (IH2) which gives the same therapeutic effect as INH but is more stable and enhances the drug loading in PLGA NPs by 15-fold compared to INH. The optimized formulation was characterized using particle size analyzer, scanning electron microscopy and transmission electron microscopy. The drug release from NPs and stability of drug were tested in different pH conditions. Results It was found that RIF and IH2 loaded in NPs release in a slow and sustained manner over a period of 1 month and they are more stable in NPs formulation compared to the free form. RIF- and IH2-loaded NPs were tested for antimicrobial susceptibility against Mycobacterium tuberculosis H37Rv strain. RIF loaded in PLGA NPs consistently inhibited the growth at 70% of the minimum inhibitory concentration (MIC) of pure RIF (MIC level 1 µg/mL), and pure IH2 and IH2-loaded NPs showed inhibition at MIC equivalent to the MIC of INH (0.1 µg/mL). Conclusion These results show that NP formulations will improve the efficacy of drug delivery for TB treatment. more...
- Published
- 2018
38. Anthelmintic and Antibacterial Screening of a New Series ofN-[4-(4-Nitrophenoxy)phenyl]-4-(Substituted)-1,3-Thiazol-2-Amines
- Author
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Namratha Bhandari and Santosh L. Gaonkar
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General Medicine - Published
- 2016
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39. Synthesis of new 4[4-(4-nitrophenoxy)phenyl]-5-substituted-2H-1,2,4-triazole-3-thiones and their evaluation as anthelmintics
- Author
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B Namratha, Dinesh Bilehal, V. ShyamKumar, and Santosh L. Gaonkar
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010405 organic chemistry ,Triazole ,1,2,4-Triazole ,General Chemistry ,010402 general chemistry ,01 natural sciences ,Combinatorial chemistry ,0104 chemical sciences ,Catalysis ,Nitroscanate ,chemistry.chemical_compound ,chemistry ,medicine ,Anthelmintic ,Benzene ,Single crystal ,medicine.drug - Abstract
A library of novel 4-[4-(4-nitrophenoxy)phenyl]-5-substituted-2H-1,2,4-triazole-3-thiones containing different substituents at the 5-position is synthesized. The mechanochemical treatment is followed to synthesize target compounds 8 (a–p), and the yields are compared by both the grinding method and the conventional method. The structure of the intermediate, isothiocyanato-4-(4-nitrophenoxy)benzene 6, is analyzed by single crystal X-ray studies. The title compounds are characterized by spectral and elemental analyses and further evaluated for their efficacy as anthelmintics in vitro. Compounds 8c, 8j, 8k, 8l, and 8m exhibit significant anthelmintic activity. more...
- Published
- 2015
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40. A facile synthesis of N-substituted 2,5-dimethylpyrroles with saccharin as a green catalyst
- Author
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Namratha Bhandari and Santosh L. Gaonkar
- Subjects
chemistry.chemical_compound ,Chemistry ,Organic Chemistry ,Organic chemistry ,Methanol ,Saccharin ,Catalysis ,Pyrrole - Abstract
The paper describes a convenient method for the preparation of N-substituted 2,5-dimethylpyrroles using edible sweetener saccharin. Various heterocyclic and aromatic hydrazides have been converted to their corresponding Paal–Knorr pyrroles at room temperature in methanol with saccharin as a green catalyst. Saccharin can be recycled for the next two runs without apparent loss in its activity. Here we propose a method which is speedy, proficient, and ecologically safe. more...
- Published
- 2015
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41. Neutralization of Haemorrhagic Activity of Viper Venoms by 1-(3-Dimethylaminopropyl)-1-(4-Fluorophenyl)-3-Oxo-1,3-Dihydroisobenzofuran-5-Carbonitrile
- Author
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B. S. Priya, Shivananju Nanjunda Swamy, Santosh L. Gaonkar, Kesturu S. Girish, Basappa, Mahadevappa Hemshekhar, Kempaiah Kemparaju, Muthuvel Suresh Kumar, Kabburalli Sunitha, Martin Sebastin Santhosh, and Kanchugarakoppal S. Rangappa more...
- Subjects
Pharmacology ,Crotalus atrox ,medicine.medical_specialty ,VIPeR ,biology ,Venom ,General Medicine ,Toxicology ,biology.organism_classification ,Viper Venoms ,Surgery ,Echis carinatus ,Echis ,Snake venom ,medicine ,Envenomation - Abstract
Viper envenomation undeniably induces brutal local manifestations such as haemorrhage, oedema and necrosis involving massive degradation of extracellular matrix at the bitten region and many a times results in dangerous systemic haemorrhage including pulmonary shock. Snake venom metalloproteases (SVMPs) are being considered to be the primary culprits for the venom-induced haemorrhage. As a consequence, the venom researchers and medical practitioners are in deliberate quest of SVMP inhibitors. In this study, we evaluated the inhibitory effect of 1-(3-dimethylaminopropyl)-1-(4-fluorophenyl)-3-oxo-1,3-dihydroisobenzofuran-5-carbonitrile (DFD) on viper venom-induced haemorrhagic and PLA2 activities. DFD effectively neutralized the haemorrhagic activity of the medically important viper venoms such as Echis carinatus, Echis ocelatus, Echis carinatus sochureki, Echis carinatus leakeyi and Crotalus atrox in a dose-dependent manner. The histological examinations revealed that the compound DFD effectively neutralizes the basement membrane degradation, and accumulation of inflammatory leucocytes at the site of Echis carinatus venom injection further confirms the inhibition of haemorrhagic activity. In addition, DFD dose dependently inhibited the PLA2 activities of Crotalus atrox and E. c. leakeyi venoms. According to the docking studies, DFD binds to hydrophobic pocket of SVMP with the ki of 19.26 × 10−9 (kcal/mol) without chelating Zn2+ in the active site. It is concluded that the clinically approved inhibitors of haemorrhagins could be used as a potent first-aid agent in snakebite management. Furthermore, a high degree of structural and functional homology between SVMPs and their relatives, the MMPs, suggests that DFD analogues may find immense value in the regulation of multifactorial pathological conditions like inflammation, cancer and wound healing. more...
- Published
- 2011
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42. Applications of Azoalkenes in the Synthesis of Fused Ring Pyridazine Derivatives
- Author
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Santosh L. Gaonkar and K. M. Lokanatha Rai
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Pyridazine ,chemistry.chemical_compound ,chemistry ,Yield (chemistry) ,Organic Chemistry ,Polymer chemistry ,Organic chemistry ,Ring (chemistry) ,Triethylamine - Abstract
Cyclic ketohydrazones containing α-methylene group are oxidized by chloramine-T followed by treatment with triethylamine leads to the formation of azoalkenes via azochloride, which are trapped by olefinic compounds to produce fused ring pyridazine derivatives in good yield. more...
- Published
- 2014
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43. Microwave-assisted synthesis of the antihyperglycemic drug rosiglitazone
- Author
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Hiroki Shimizu and Santosh L. Gaonkar
- Subjects
Drug ,Stereochemistry ,Chemistry ,media_common.quotation_subject ,Organic Chemistry ,Total synthesis ,Biochemistry ,High yielding ,Chemical synthesis ,Combinatorial chemistry ,Microwave assisted ,Microwave heating ,Drug Discovery ,medicine ,Rosiglitazone ,Microwave ,media_common ,medicine.drug - Abstract
We developed a simple, rapid, high yielding, and environmentally benign microwave assisted total synthesis of rosiglitazone, an antihyperglycemic agent for diabetes mellitus Type II. We used microwave heating successfully to improve reactions in four of six steps and obtain quicker and higher yields. In addition, all intermediates were isolated in good yields with crystallizations only and did not require chromatographic separations. more...
- Published
- 2010
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44. Microwave-Assisted Solvent-Free Synthesis of N-alkyl Benzotriazole Derivatives: Antimicrobial Studies
- Author
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Raghu Ningegowda, Kanchugarakoppal S. Rangappa, C. V. Kavitha, Santosh L. Gaonkar, Mysore V. Tejesvi, B. S. Priya, and S. Nanjunda Swamy
- Subjects
Biphenyl ,chemistry.chemical_classification ,Benzotriazole ,Pharmaceutical Science ,Halide ,Antimicrobial ,Combinatorial chemistry ,In vitro ,Solvent ,chemistry.chemical_compound ,chemistry ,Drug Discovery ,Molecular Medicine ,Organic chemistry ,Antibacterial activity ,Alkyl - Abstract
To elucidate further our structural activity relation on the chemistry and antimicrobial activity, a series of novel N-alkylated benzotriazole derivatives bearing pharmaceutically important substituted biphenyl and benzyl halides were synthesized. The synthesized compounds were characterized and tested for in vitro antimicrobial activities by MIC determination against a panel of susceptible and resistant Gram-positive and Gram-negative microorganisms. The synthesis has been carried out using microwave irradiation method with solvent and without solvent. The obtained results showed high yields. Interestingly, compounds 2a and 2b showed a two fold increased antibacterial activity than the standard drug tested and the compounds 2d and 2e showed potent antifungal activity than the standard drug tested. more...
- Published
- 2009
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45. Microwave-assisted synthesis and evaluation of anti-inflammatory activity of new series of N-substituted 2-butyl-5-chloro-3H-imidazole-4-carbaldehyde derivatives
- Author
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K. M. Lokanatha Rai, Santosh L. Gaonkar, and N. Suchetha Shetty
- Subjects
medicine.drug_class ,Chemistry ,Organic Chemistry ,Rat model ,Ibuprofen ,Medicinal chemistry ,Microwave assisted ,Anti-inflammatory ,chemistry.chemical_compound ,Yield (chemistry) ,Microwave irradiation ,medicine ,Organic chemistry ,Imidazole ,General Pharmacology, Toxicology and Pharmaceutics ,medicine.drug ,Paw edema - Abstract
A series of N-substituted 2-butyl-5-chloro-3H-imidazole-4-carbaldehyde derivatives bearing potentially bioactive substituents were synthesized by microwave irradiation method in good yield compared with conventional method. The synthesized compounds were screened for their anti-inflammatory activity and were compared with a standard drug. The compounds demonstrated potent to weak anti-inflammatory activity. Of the compounds studied, compounds 6i and 6d showed potent activity comparable to the standard drug ibuprofen at the same dose in carrageenan-induced paw edema in rat model. more...
- Published
- 2008
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46. Synthesis of novel 3-[5-ethyl-2-(2-phenoxy-ethyl)-pyridin]-5-substituted isoxazoline libraries via 1,3-dipolar cycloaddition and evaluation of antimicrobial activities
- Author
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K. M. Lokanatha Rai, Santosh L. Gaonkar, and B. Prabhuswamy
- Subjects
Nitrile ,Chemistry ,Organic Chemistry ,Moderate activity ,Antimicrobial ,Ring (chemistry) ,Combinatorial chemistry ,Cycloaddition ,Pyridine moiety ,chemistry.chemical_compound ,Chloramine-T ,1,3-Dipolar cycloaddition ,Organic chemistry ,General Pharmacology, Toxicology and Pharmaceutics - Abstract
A series of novel 3-[5-ethyl-2-(2-phenoxy-ethyl)-pyridin]-5-substituted isoxazolines were synthesized via 1,3-dipolar cycloaddition of in situ generated nitrile oxide from 4-[2-(5-ethylpyridyl)-ethoxy]-benzaldoxime with alkenes to obtain new heterocyclic libraries containing a pyridine moiety in addition to the isoxazoline ring. The newly synthesized compounds were screened for their antimicrobial activity and were compared with standard drugs. The compounds demonstrated potent to weak antimicrobial activity. Of the compounds studied, compounds 3c and 3f showed significant antibacterial as well as antifungal activity. Compounds 3e and 3g showed moderate activity. The title compounds represent a novel class of potent antimicrobial agents. more...
- Published
- 2007
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47. ChemInform Abstract: A Facile Synthesis of N-Substituted 2,5-Dimethylpyrroles with Saccharin as a Green Catalyst
- Author
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Santosh L. Gaonkar and Namratha Bhandari
- Subjects
chemistry.chemical_compound ,chemistry ,Organic chemistry ,General Medicine ,Methanol ,Saccharin ,Pyrrole derivatives ,Catalysis - Abstract
The paper describes a convenient method for the preparation of N-substituted 2,5-dimethylpyrroles using edible sweetener saccharin. Various heterocyclic and aromatic hydrazides have been converted to their corresponding Paal–Knorr pyrroles at room temperature in methanol with saccharin as a green catalyst. Saccharin can be recycled for the next two runs without apparent loss in its activity. Here we propose a method which is speedy, proficient, and ecologically safe. more...
- Published
- 2015
- Full Text
- View/download PDF
48. Synthesis and antimicrobial studies of a new series of 2-{4-[2-(5-ethylpyridin-2-yl)ethoxy]phenyl}-5-substituted-1,3,4-oxadiazoles
- Author
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K. M. L. Rai, B. Prabhuswamy, and Santosh L. Gaonkar
- Subjects
Pharmacology ,Oxadiazoles ,Molecular Structure ,Pyridines ,Organic Chemistry ,Ether ,General Medicine ,Antimicrobial ,Chemical synthesis ,Benzaldehyde ,Structure-Activity Relationship ,chemistry.chemical_compound ,Minimum inhibitory concentration ,Anti-Infective Agents ,chemistry ,Gram-Negative Bacteria ,Drug Discovery ,Chloramine-T ,Alkoxy group ,Organic chemistry ,Bacillus subtilis ,Antibacterial agent - Abstract
A series of novel 2-{4-[2-(5-ethylpyridin-2-yl)ethoxy]phenyl}-5-substituted-1,3,4-oxadiazoles were synthesized by the oxidative cyclisation of hydrazones derived from 4-[2-(5-ethylpyridin-2-yl)ethoxy]benzaldehyde and aroylhydrazines using chloramine-T as oxidant. IR, NMR and elemental analysis characterized the newly synthesized compounds. The synthesized compounds were evaluated for their antimicrobial activity and were compared with standard drugs. The compounds demonstrated potent to weak antimicrobial activity. Out of the compounds studied, compounds 8c and 8d showed significant inhibition. Compounds 8b , 8f , 8k and 8e showed moderate activity. The minimum inhibitory concentration of the compounds was in the range of 8–26 μg ml –1 against bacteria and 8–24 μg ml –1 against fungi. The title compounds represent a novel class of potent antimicrobial agents. more...
- Published
- 2006
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49. A new method for the generation of α-nitrosoolefins from ketooximes and its application to the synthesis of 5,6-dihydro-4H-1,2-oxazine derivatives
- Author
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K. M. Lokanatha Rai and Santosh L. Gaonkar
- Subjects
In situ ,Organic reaction ,Group (periodic table) ,Chemistry ,Yield (chemistry) ,Organic Chemistry ,Organic chemistry - Abstract
Reaction of ketooximes containing α-methylene group with chloramine-T followed by treatment with tri-ethylamine leads to the formation of α-nitrosoolefins via α-nitrosochloride, which can react in situ intermol-ecularly with olefinic compounds to produce 5,6-dihydro-4H-1,2-oxazine derivatives in good yield. more...
- Published
- 2005
- Full Text
- View/download PDF
50. Synthesis and Antimicrobial Screening of Novel 4-Substituted Phenyl-5-[1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-yl]-2H-1,2,4-triazole-3-thiones
- Author
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Santosh L. Gaonkar and Namratha Bhandari
- Subjects
Antifungal ,chemistry.chemical_compound ,Article Subject ,Isobenzofuran ,chemistry ,medicine.drug_class ,medicine ,Proton NMR ,1,2,4-Triazole ,Carbon-13 NMR ,Antimicrobial screening ,Medicinal chemistry ,Research Article - Abstract
The paper describes a convenient method for the preparation of 4-substituted phenyl-5-[1-(4-fluorophenyl)-1,3-dihydroisobenzofuran-5-yl]-2H-1,2,4-triazole-3-thiones. The structures of the synthesized compounds are established by the results of LCMS, 1H NMR, 13C NMR, and IR and elemental analyses. The mercaptotriazoles are indicated to be in thione form by 1H NMR spectra. All the synthesized compounds have been screened for antibacterial and antifungal activities. Compounds 12d and 12h exhibit encouraging results, while the remaining compounds show moderate activities. On the basis of spectral studies, formation of 2-amino-1,3,4-thiadiazoles from the isobenzofuran acyl thiosemicarbazides 11(a–h) is ruled out. more...
- Published
- 2014
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