Browsing by Author "Nayak, N."

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A study on the behavior of CO2 corrosion on pipeline using computational fluid dynamics, experimental and artificial neural network approach
(IOP Publishing Ltd custserv@iop.org, 2020) Nayak, N.; Anarghya, A.; Al Adhoubi, M.
Corrosion of the piping systemis a genuine problem in the oil and gas industry.Most oil and gas industries used a carbon steel pipeline for the transportation of crude oil, which is affected by CO2 corrosion. Now a day, the computational approach and artificial neural network approach will be used to study the corrosion rate. Therefore, in this work, Computational Fluid Dynamics (CFD) and Artificial Neural Network (ANN) studies on piping systems were made to determine the corrosion rate induced byCO2 saturated aqueous solutions on carbon steel pipeline. In CFD study, corrosion rates were computed by modeling the electrochemical processes occurring at themetal substrate fromcathodic reductions of the carbonic acid and hydrogen ions, and the anodic oxidation of the metal component. Also, an artificial neural network study wasmade using a multilayer perceptron neural network method; and, computational fluid dynamics and artificial neural network simulations were validated with in-house built experiment set-up. The experimental study had been carried out for more than 200-h to find the corrosion rate on the pipeline, and satisfactory trendswere observed between computational fluid dynamics, artificial neural network, and experimental values. In the end, corroded pipes were observed under a scanning electron microscope and X-ray spectroscopy, and the corroded zones were viewed as against the non-corroded pipe. © 2020 IOP Publishing Ltd.
Design of new phenothiazine-thiadiazole hybrids via molecular hybridization approach for the development of potent antitubercular agents
(2015) Ramprasad, J.; Nayak, N.; Udayakumar, D.
A new library of phenothiazine and 1,3,4-thiadiazole hybrid derivatives (5a-u) was designed based on the molecular hybridization approach and the molecules were synthesized in excellent yields using a facile single-step chloro-amine coupling reaction between 2-chloro-1-(10H-phenothiazin-10-yl)ethanones and 2-amino-5-subsituted-1,3,4-thiadiazoles. The compounds were evaluated for their in vitro inhibition activity against Mycobacterium tuberculosis H37Rv (MTB). Compounds 5g and 5n were emerged as the most active compounds of the series with MIC of 0.8 ?g/mL (?1.9 ?M). Also, compounds 5a, 5b, 5c, 5e, 5l and 5m (MIC = 1.6 ?g/mL), and compounds 5j, 5k and 5o (MIC = 3.125 ?g/mL) showed significant inhibition activity. The structure-activity relationship demonstrated that an alkyl (methyl/npropyl) or substituted (4-methyl/4-Cl/4-F) phenyl groups on the 1,3,4-thiadiazole ring enhance the inhibition activity of the compounds. The cytotoxicity study revealed that none of the active molecules are toxic to a normal Vero cell line thus proving the lack of general cellular toxicity. Further, the active molecules were subjected to molecular docking studies with target enzymes InhA and CYP121. 2015 Elsevier Masson SAS. All rights reserved.
Design of new phenothiazine-thiadiazole hybrids via molecular hybridization approach for the development of potent antitubercular agents
(Elsevier Masson SAS 62 rue Camille Desmoulins Issy les Moulineaux Cedex 92442, 2015) Ramprasad, J.; Nayak, N.; Udayakumar, U.
A new library of phenothiazine and 1,3,4-thiadiazole hybrid derivatives (5a-u) was designed based on the molecular hybridization approach and the molecules were synthesized in excellent yields using a facile single-step chloro-amine coupling reaction between 2-chloro-1-(10H-phenothiazin-10-yl)ethanones and 2-amino-5-subsituted-1,3,4-thiadiazoles. The compounds were evaluated for their in vitro inhibition activity against Mycobacterium tuberculosis H37Rv (MTB). Compounds 5g and 5n were emerged as the most active compounds of the series with MIC of 0.8 ?g/mL (?1.9 ?M). Also, compounds 5a, 5b, 5c, 5e, 5l and 5m (MIC = 1.6 ?g/mL), and compounds 5j, 5k and 5o (MIC = 3.125 ?g/mL) showed significant inhibition activity. The structure-activity relationship demonstrated that an alkyl (methyl/npropyl) or substituted (4-methyl/4-Cl/4-F) phenyl groups on the 1,3,4-thiadiazole ring enhance the inhibition activity of the compounds. The cytotoxicity study revealed that none of the active molecules are toxic to a normal Vero cell line thus proving the lack of general cellular toxicity. Further, the active molecules were subjected to molecular docking studies with target enzymes InhA and CYP121. © 2015 Elsevier Masson SAS. All rights reserved.
Design, Synthesis, and Biological Evaluation of New 8-Trifluoromethylquinoline Containing Pyrazole-3-carboxamide Derivatives
(2017) Nayak, N.; Ramprasad, J.; Udayakumar, D.
The article describes the design, synthesis, and characterization of a new series of 8-trifluoromethylquinoline substituted pyrazole-3-carboxamides (9a, 9b, 9c, 9d, 9e, 9f, 9g, 9h, 9i, 9j, 9k, 9l, 9m, 9n, 9o, 9p, 9q, 9r, 9s, 9t) derived from different primary and secondary amines. The intermediate and target compounds were characterized using spectroscopic methods. The structures of intermediate 7 and target molecule 9d were evidenced by the single crystal X-ray study. All the synthesized target compounds (9a, 9b, 9c, 9d, 9e, 9f, 9g, 9h, 9i, 9j, 9k, 9l, 9m, 9n, 9o, 9p, 9q, 9r, 9s, 9t) and three intermediates (6, 7, 8) were screened for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv strain. Two compounds, 9k and 9t, showed significant inhibition activity with MIC of 3.13 g/mL, which is comparable with the activity of standard drug, ethambutol. The carboxamides derived from benzylamine derivatives were more active than their aniline analogs. In general, the hybrid amides with a N-methylene linkage (-CONHCH2-) exhibited enhanced antitubercular activity. In the antibacterial screening, intermediate 3-hydrazinyl-2-methyl-8-(trifluoromethyl)quinoline (6) displayed remarkable activity against the tested bacterial strains. Further, the active anti-TB derivatives were non-toxic to benign NIH 3T3 cells, which demonstrate the lack of general cellular toxicity and hence signifies their suitability for further lead development. 2015 HeteroCorporation
Design, Synthesis, and Biological Evaluation of New 8-Trifluoromethylquinoline Containing Pyrazole-3-carboxamide Derivatives
(HeteroCorporation, 2017) Nayak, N.; Ramprasad, J.; Udayakumar, U.
The article describes the design, synthesis, and characterization of a new series of 8-trifluoromethylquinoline substituted pyrazole-3-carboxamides (9a, 9b, 9c, 9d, 9e, 9f, 9g, 9h, 9i, 9j, 9k, 9l, 9m, 9n, 9o, 9p, 9q, 9r, 9s, 9t) derived from different primary and secondary amines. The intermediate and target compounds were characterized using spectroscopic methods. The structures of intermediate 7 and target molecule 9d were evidenced by the single crystal X-ray study. All the synthesized target compounds (9a, 9b, 9c, 9d, 9e, 9f, 9g, 9h, 9i, 9j, 9k, 9l, 9m, 9n, 9o, 9p, 9q, 9r, 9s, 9t) and three intermediates (6, 7, 8) were screened for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv strain. Two compounds, 9k and 9t, showed significant inhibition activity with MIC of 3.13 µg/mL, which is comparable with the activity of standard drug, ethambutol. The carboxamides derived from benzylamine derivatives were more active than their aniline analogs. In general, the hybrid amides with a N-methylene linkage (-CONHCH2-) exhibited enhanced antitubercular activity. In the antibacterial screening, intermediate 3-hydrazinyl-2-methyl-8-(trifluoromethyl)quinoline (6) displayed remarkable activity against the tested bacterial strains. Further, the active anti-TB derivatives were non-toxic to benign NIH 3T3 cells, which demonstrate the lack of general cellular toxicity and hence signifies their suitability for further lead development. © 2015 HeteroCorporation
Development of micromixer for efficient mixing of blood and insulin in human arteries
(Elsevier Ltd, 2023) Bagde, P.; Nayak, N.; Arumuga Perumal, D.
In the present work, the computational analysis of passive micromixer with embedded obstacles is studied in detail. It also focuses on Y shaped microchannel with internal embedded obstacles. Different types of Y shaped microchannels are designed by altering the cross section, mixing length and number of obstacles. For simplicity, same velocities at both blood and insulin inlets are assumed. Microchannels are designed in CATIA V5 software and simulations were performed using ANSYS CFX 19.0 solver for steady state condition. Identification of geometric variables correlation with flow field variables is considered for better mixing design. Simulation results are compared with the help of calculating volume fraction at each section and average volume fraction at outlet with each other. It is found that, microchannel having rectangular cross section with circular and rectangular obstacles with reduced length for insulin inlet is giving highest average volume fraction at outlet. Also, one with elliptical cross section is able to give uniform average volume fraction at outlet. By observing mixing profile, it is seen that there is significant increase in mixing behaviour by introducing embedded obstacles as compared to without using it. Â© 2022
Ionic liquid-promoted one-pot synthesis of thiazole-imidazo[2,1-b][1,3,4]thiadiazole hybrids and their antitubercular activity
(2016) Ramprasad, J.; Nayak, N.; Udayakumar, D.; Yogeeswari, P.; Sriram, D.
In this paper, we report the facile and efficient one-pot three-component synthesis of 1-((6-phenylimidazo[2,1-b][1,3,4]thiadiazol-5-yl)methylene)-2-(4-phenylthiazol-2-yl)hydrazine derivatives (5a-w) using an ionic liquid, namely 1-butyl-3-methylimidazolium bromide ([Bmim]Br). The compounds were screened for their in vitro antimycobacterial activity against Mycobacterium tuberculosis. Compound 5s showed the highest inhibitory activity with an MIC of 6.03 ?M which is slightly lower than the MIC values of standard drugs ethambutol (15.3 ?M) and ciprofloxacin (9.4 ?M). Four other compounds of the series viz.5e, 5i, 5t and 5w also showed significant inhibitory activity with MIC values in the range of 11.7-13.9 ?M. The structure-activity relationship revealed that the trifluoromethyl substitution at position-2 and p-chlorophenyl substitution at position-6 of the imidazo[2,1-b][1,3,4]thiadiazole ring enhanced the inhibitory activity. Also, the methyl, methoxy, fluoro or nitro substituents on the thiazole ring enhanced the activity of the compounds. None of the active compounds were toxic to a normal cell line (NIH 3T3), which signifies the lack of general cellular toxicity of the molecules. In silico molecular docking studies revealed the favourable interaction of the potent compounds with the target enzymes InhA and CYP121. The Royal Society of Chemistry 2016.
Ionic liquid-promoted one-pot synthesis of thiazole-imidazo[2,1-b][1,3,4]thiadiazole hybrids and their antitubercular activity
(Royal Society of Chemistry, 2016) Ramprasad, J.; Nayak, N.; Udayakumar, D.; Yogeeswari, P.; Sriram, D.
In this paper, we report the facile and efficient one-pot three-component synthesis of 1-((6-phenylimidazo[2,1-b][1,3,4]thiadiazol-5-yl)methylene)-2-(4-phenylthiazol-2-yl)hydrazine derivatives (5a-w) using an ionic liquid, namely 1-butyl-3-methylimidazolium bromide ([Bmim]Br). The compounds were screened for their in vitro antimycobacterial activity against Mycobacterium tuberculosis. Compound 5s showed the highest inhibitory activity with an MIC of 6.03 ?M which is slightly lower than the MIC values of standard drugs ethambutol (15.3 ?M) and ciprofloxacin (9.4 ?M). Four other compounds of the series viz.5e, 5i, 5t and 5w also showed significant inhibitory activity with MIC values in the range of 11.7-13.9 ?M. The structure-activity relationship revealed that the trifluoromethyl substitution at position-2 and p-chlorophenyl substitution at position-6 of the imidazo[2,1-b][1,3,4]thiadiazole ring enhanced the inhibitory activity. Also, the methyl, methoxy, fluoro or nitro substituents on the thiazole ring enhanced the activity of the compounds. None of the active compounds were toxic to a normal cell line (NIH 3T3), which signifies the lack of general cellular toxicity of the molecules. In silico molecular docking studies revealed the favourable interaction of the potent compounds with the target enzymes InhA and CYP121. © The Royal Society of Chemistry 2016.
New INH-pyrazole analogs: Design, synthesis and evaluation of antitubercular and antibacterial activity
(2015) Nayak, N.; Ramprasad, J.; Udayakumar, D.
With the aim of developing promising antitubercular and antibacterial leads, we have designed and synthesized a new series of isonicotinohydrazide based pyrazole derivatives (5a-r). All new derivatives (4a-b and 5a-r) were screened for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv (MTB) strain. Four compounds 5j, 5k, 5l and 4b emerged as promising antitubercular agents with MIC of ?4.9 ?M which is much lower than the MIC of the first line antitubercular drug, ethambutol. The 3-chlorophenyl substituent at position-3 of the pyrazole ring enhanced the antiTB activity of the molecules. Three derivatives 5b, 5k and 4b exhibited promising antibacterial activity against the tested bacterial strains. The active molecules were nontoxic to normal Vero cells and showed high selectivity index (>160). The structure and antitubercular activity relationship was further supported by in silico molecular docking study of the active compounds against enoyl acyl carrier protein reductase (InhA) enzyme of M. tuberculosis. 2015 Published by Elsevier Ltd.
New INH-pyrazole analogs: Design, synthesis and evaluation of antitubercular and antibacterial activity
(Elsevier Ltd, 2015) Nayak, N.; Ramprasad, J.; Udayakumar, U.
With the aim of developing promising antitubercular and antibacterial leads, we have designed and synthesized a new series of isonicotinohydrazide based pyrazole derivatives (5a-r). All new derivatives (4a-b and 5a-r) were screened for in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv (MTB) strain. Four compounds 5j, 5k, 5l and 4b emerged as promising antitubercular agents with MIC of ?4.9 ?M which is much lower than the MIC of the first line antitubercular drug, ethambutol. The 3-chlorophenyl substituent at position-3 of the pyrazole ring enhanced the antiTB activity of the molecules. Three derivatives 5b, 5k and 4b exhibited promising antibacterial activity against the tested bacterial strains. The active molecules were nontoxic to normal Vero cells and showed high selectivity index (>160). The structure and antitubercular activity relationship was further supported by in silico molecular docking study of the active compounds against enoyl acyl carrier protein reductase (InhA) enzyme of M. tuberculosis. © 2015 Published by Elsevier Ltd.
One-pot synthesis of new triazole - Imidazo[2,1-b][1,3,4]thiadiazole hybrids via click chemistry and evaluation of their antitubercular activity
(2015) Ramprasad, J.; Nayak, N.; Udayakumar, D.; Yogeeswari, P.; Sriram, D.
A new series of triazole-imidazo[2,1-b][1,3,4]thiadiazole hybrids (6a-s, 7a) were designed by a molecular hybridisation approach and the target molecules were synthesized via one pot click chemistry protocol. All the intermediates and final molecules were characterised using spectral methods and one of the target compounds (6c) was analysed by the single crystal XRD study. The derivatives were screened for their antimycobacterial activity against Mycobacterium tuberculosis H37Rv strain. Two compounds, 6f and 6n, demonstrated significant growth inhibitory activity against the bacterial strain with a MIC of 3.125 ?g/mL. The presence of chloro substituent on the imidazo[2,1-b][1,3,4]thiadiazole ring and ethyl, benzyl or cyanomethylene groups on the 1,2,3-triazole ring enhance the inhibition activity of the molecules. The active compounds are not toxic to a normal cell line which signifies the lack of general cellular toxicity of these compounds. 2015 Elsevier Ltd. All rights reserved.
One-pot synthesis of new triazole - Imidazo[2,1-b][1,3,4]thiadiazole hybrids via click chemistry and evaluation of their antitubercular activity
(Elsevier Ltd, 2015) Ramprasad, J.; Nayak, N.; Udayakumar, U.; Yogeeswari, P.; Sriram, D.
A new series of triazole-imidazo[2,1-b][1,3,4]thiadiazole hybrids (6a-s, 7a) were designed by a molecular hybridisation approach and the target molecules were synthesized via one pot click chemistry protocol. All the intermediates and final molecules were characterised using spectral methods and one of the target compounds (6c) was analysed by the single crystal XRD study. The derivatives were screened for their antimycobacterial activity against Mycobacterium tuberculosis H37Rv strain. Two compounds, 6f and 6n, demonstrated significant growth inhibitory activity against the bacterial strain with a MIC of 3.125 ?g/mL. The presence of chloro substituent on the imidazo[2,1-b][1,3,4]thiadiazole ring and ethyl, benzyl or cyanomethylene groups on the 1,2,3-triazole ring enhance the inhibition activity of the molecules. The active compounds are not toxic to a normal cell line which signifies the lack of general cellular toxicity of these compounds. © 2015 Elsevier Ltd. All rights reserved.
Optimized ANN-GA and experimental analysis of the performance and combustion characteristics of HCCI engine
(2018) Anarghya, A.; Rao, N.; Nayak, N.; Tirpude, A.R.; Harshith, D.N.; Samarth, B.R.
HCCI (Homogeneous Charge Compression Ignition) engine has the benefit of operating at high thermal efficiency and low emissions of NOx and soot. However, it has challenges of complex combustion phase controlling and low operating range. This research work investigated the performance and combustion characteristics of HCCI engine with numerical simulations on ANSYS FLUENT and neural network models. The numerical and neural network results were validated by experimental observations with different fuel properties and reduced valve lifts for trapping of the exhaust gases. Experiments were performed on a SMART engine for different speeds and inlet air temperature, with various reference fuels (PRF30, PRF50, PRF70) and methanol to validate the CFD and ANN-GA observations. The engine performance was analyzed for IMEP, ISFC and thermal efficiency, which were found to be 8.2 bar, 205 g/kWh and 44.5% respectively as the optimum performance with PRF-70 fuel. The trapping of the residual gases was performed with various fuel blends in order to overcome the cyclic variations and to improve the operating zones near the knock boundary. The heat release rate was significantly reduced with trapped exhaust gases, and operating region was improved with the use of methanol fuel. Overall the trapping of the hot residual gases resulted in the maximum increase in the operating region by 12% and reduced cyclic variations by 15% for methanol fuel. The exhaust emissions were analyzed and ultra-low emissions of NOx at lean operating conditions were observed with the reduced valve lifts. The study results indicated thermal NO emissions on an average were decreased by 7.8%, CO emissions reduced by 6% and HC emissions increased by 9%. Methanol had ultra-low emissions of HC and CO, but higher emissions of NO and PRF30 had lower emissions of NO. However, ANN-GA model gave satisfactory combustion characteristics and emissions with respect to experimental results. Thus, CFD simulations, Neural Network methods and experimental study gave valuable thoughts of trapped residual gases approach on performance, combustion and emission characteristics of HCCI with PRF's and methanol fuel. 2017 Elsevier Ltd
Synthesis and antimycobacterial screening of new N-(4-(5-aryl-3-(5-methyl-1,3,4-oxadiazol-2-yl)-1H-pyrazol-1-yl)phenyl)-4-amide derivatives
(2016) Nayak, N.; Ramprasad, J.; Udayakumar, D.; Yogeeswari, P.; Sriram, D.
This article demonstrates the synthesis, characterization and the study of in vitro antitubercular activities of twenty four new N-(4-(5-aryl-3-(5-methyl-1,3,4-oxadiazol-2-yl)-1H-pyrazol-1-yl)phenyl)-4-amide derivatives (8a-x). The antitubercular activity of the compounds against Mycobacterium tuberculosis H37Rv (MTB) revealed that 2-chloro-N-(4-(5-(4-chlorophenyl)-3-(5-methyl-1,3,4-oxadiazol-2-yl)-1H-pyrazol-1-yl)phenyl)benzamide (8n) is the most promising lead molecule with a MIC of 1.56 ?g/mL, while the corresponding unsubstituted benzamide derivative (8o) is the next most active molecule with a MIC of 3.13 ?g/mL. Interestingly, the pyrazole intermediate 5b containing chlorophenyl and N-acylcarbohydrazide substituents also showed significant activity (MIC = 3.13 ?g/mL). Further, the active molecules did not show toxicity against a normal NIH 3T3 cell line, signifying their suitability for further drug development. 2016 Udayakumar Dalimba.
Synthesis and antimycobacterial screening of new N-(4-(5-aryl-3-(5-methyl-1,3,4-oxadiazol-2-yl)-1H-pyrazol-1-yl)phenyl)-4-amide derivatives
(Elsevier, 2016) Nayak, N.; Ramprasad, J.; Udayakumar, D.; Yogeeswari, P.; Sriram, D.
This article demonstrates the synthesis, characterization and the study of in vitro antitubercular activities of twenty four new N-(4-(5-aryl-3-(5-methyl-1,3,4-oxadiazol-2-yl)-1H-pyrazol-1-yl)phenyl)-4-amide derivatives (8a-x). The antitubercular activity of the compounds against Mycobacterium tuberculosis H37Rv (MTB) revealed that 2-chloro-N-(4-(5-(4-chlorophenyl)-3-(5-methyl-1,3,4-oxadiazol-2-yl)-1H-pyrazol-1-yl)phenyl)benzamide (8n) is the most promising lead molecule with a MIC of 1.56 ?g/mL, while the corresponding unsubstituted benzamide derivative (8o) is the next most active molecule with a MIC of 3.13 ?g/mL. Interestingly, the pyrazole intermediate 5b containing chlorophenyl and N-acylcarbohydrazide substituents also showed significant activity (MIC = 3.13 ?g/mL). Further, the active molecules did not show toxicity against a normal NIH 3T3 cell line, signifying their suitability for further drug development. © 2016 Udayakumar Dalimba.
Synthesis and antitubercular and antibacterial activity of some active fluorine containing quinoline pyrazole hybrid derivatives
(2016) Nayak, N.; Ramprasad, J.; Udayakumar, D.
In an attempt to develop newer antitubercular and antibacterial agents against the increasing bacterial resistance, we have designed new quinoline pyrazole analogs (8a u) following the molecular hybridization approach. The structure of one of the final compounds, 8a was unambiguously confirmed by single crystal X-ray diffraction (SC-XRD) analysis. The target compounds were evaluated for their antitubercular activity against Mycobacterium tuberculosis and antibacterial activity against three common pathogenic bacterial strains. Four derivatives (8b, 8c, 8j and 8o) displayed significant antitubercular activity. The compounds derived from 8-trifluoromethylquinoline and 6-fluoroquinoline scaffolds with halogen substitution on the pyrazole ring exhibited superior inhibition activity than corresponding 6-methoxyquinoline analogs. The cytotoxic studies revealed that the active compounds are nontoxic to normal Vero cell lines with selectivity index values ?10, which indicate the suitability of these compounds for further drug development. The in silico molecular docking study demonstrated strong binding affinity of the compounds with the target enzymes (InhA, CYP121 and TMPK) of M. tuberculosis. Further, the in vitro antibacterial activity of compounds 8b, 8c, 8d and 8g is comparable with that of the reference drug, Ciprofloxacin. 2016 Elsevier B.V.
Synthesis and antitubercular and antibacterial activity of some active fluorine containing quinoline–pyrazole hybrid derivatives
(Elsevier B.V., 2016) Nayak, N.; Ramprasad, J.; Udayakumar, D.
In an attempt to develop newer antitubercular and antibacterial agents against the increasing bacterial resistance, we have designed new quinoline–pyrazole analogs (8a–u) following the molecular hybridization approach. The structure of one of the final compounds, 8a was unambiguously confirmed by single crystal X-ray diffraction (SC-XRD) analysis. The target compounds were evaluated for their antitubercular activity against Mycobacterium tuberculosis and antibacterial activity against three common pathogenic bacterial strains. Four derivatives (8b, 8c, 8j and 8o) displayed significant antitubercular activity. The compounds derived from 8-trifluoromethylquinoline and 6-fluoroquinoline scaffolds with halogen substitution on the pyrazole ring exhibited superior inhibition activity than corresponding 6-methoxyquinoline analogs. The cytotoxic studies revealed that the active compounds are nontoxic to normal Vero cell lines with selectivity index values ?10, which indicate the suitability of these compounds for further drug development. The in silico molecular docking study demonstrated strong binding affinity of the compounds with the target enzymes (InhA, CYP121 and TMPK) of M. tuberculosis. Further, the in vitro antibacterial activity of compounds 8b, 8c, 8d and 8g is comparable with that of the reference drug, Ciprofloxacin. © 2016 Elsevier B.V.
Synthesis and biological evaluation of new imidazo[2,1-b][1,3,4]thiadiazole-benzimidazole derivatives
(2015) Ramprasad, J.; Nayak, N.; Udayakumar, D.; Yogeeswari, P.; Sriram, D.; Peethambar, S.K.; Achur, R.; Kumar, H.S.S.
In this report, we describe the synthesis and biological evaluation of a new series of 2-(imidazo[2,1-b][1,3,4]thiadiazol-5-yl)-1H-benzimidazole derivatives (5a-ac). The molecules were analyzed by 1H NMR, 13C NMR, mass spectral and elemental data. The structure of one of the pre-final compounds, 6-(4-methoxyphenyl)-2-(4-methylphenyl)imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde (4d) and that of a target compound, 2-[2-methyl-6-(4-methyl phenyl) imidazo[2,1-b][1,3,4]thiadiazol-5-yl]-1H-benzimidazole (5aa) were confirmed by single crystal XRD studies. All the target compounds were screened for in vitro anti-tuberculosis activity against Mycobacterium tuberculosis H37Rv strain. Seven (5c, 5d, 5l, 5p, 5r, 5z and 5aa) out of twenty nine compounds showed potent anti-tubercular activity with a MIC of 3.125 ?g/mL. A p-substituted phenyl group (p-tolyl or p-chlorophenyl) in the imidazo[2,1-b][1,3,4]thiadiazole ring and/or a chloro group in the benzimidazole ring enhance anti-tuberculosis activity whereas a nitro group in the benzimidazole ring reduces the activity. In the antibacterial screening, compounds 5i, 5w and 5ac showed promising activity against the tested bacterial strains. Further, antifungal and antioxidant activities of these molecules were also investigated. In the cytotoxicity study, the active antitubercular compounds exhibited very low toxicity against a normal cell line. 2015 Elsevier Masson SAS.
Synthesis and biological evaluation of new imidazo[2,1-b][1,3,4]thiadiazole-benzimidazole derivatives
(Elsevier Masson SAS infos@masson.fr 62 rue Camille Desmoulins Issy les Moulineaux Cedex 92442, 2015) Ramprasad, J.; Nayak, N.; Udayakumar, U.; Yogeeswari, P.; Sriram, D.; Peethambar, S.K.; Achur, R.; Santosh Kumar, H.S.S.
In this report, we describe the synthesis and biological evaluation of a new series of 2-(imidazo[2,1-b][1,3,4]thiadiazol-5-yl)-1H-benzimidazole derivatives (5a-ac). The molecules were analyzed by 1H NMR, 13C NMR, mass spectral and elemental data. The structure of one of the pre-final compounds, 6-(4-methoxyphenyl)-2-(4-methylphenyl)imidazo[2,1-b][1,3,4]thiadiazole-5-carbaldehyde (4d) and that of a target compound, 2-[2-methyl-6-(4-methyl phenyl) imidazo[2,1-b][1,3,4]thiadiazol-5-yl]-1H-benzimidazole (5aa) were confirmed by single crystal XRD studies. All the target compounds were screened for in vitro anti-tuberculosis activity against Mycobacterium tuberculosis H37Rv strain. Seven (5c, 5d, 5l, 5p, 5r, 5z and 5aa) out of twenty nine compounds showed potent anti-tubercular activity with a MIC of 3.125 ?g/mL. A p-substituted phenyl group (p-tolyl or p-chlorophenyl) in the imidazo[2,1-b][1,3,4]thiadiazole ring and/or a chloro group in the benzimidazole ring enhance anti-tuberculosis activity whereas a nitro group in the benzimidazole ring reduces the activity. In the antibacterial screening, compounds 5i, 5w and 5ac showed promising activity against the tested bacterial strains. Further, antifungal and antioxidant activities of these molecules were also investigated. In the cytotoxicity study, the active antitubercular compounds exhibited very low toxicity against a normal cell line. © 2015 Elsevier Masson SAS.
Synthesis of new pyrazole-triazole hybrids by click reaction using a green solvent and evaluation of their antitubercular and antibacterial activity
(2016) Nayak, N.; Ramprasad, J.; Udayakumar, D.; Yogeeswari, P.; Sriram, D.; Kumar, H.S.S.; Peethambar, S.K.; Achur, R.
A new series of pyrazole-based 1,2,3-triazole derivatives (6a-x) were synthesized by employing click reaction using a 2:1 mixture of PEG-400 and water as green solvent. The synthesized intermediate and final compounds were characterized by 1H NMR, 13C NMR, and mass spectra and elemental analysis techniques. The structure of one of the final compounds, 6a was evidenced by single crystal X-ray diffraction study. Among the twenty-four compounds, five compounds (6a, 6b, 6d, 6f, and 6g) showed significant antitubercular activity against Mycobacterium tuberculosis H37Rv with a minimum inhibitory concentration (MIC) ? 6.25 ?g/mL. The 4-(((5-(4-Chlorophenyl)-1-phenyl-1H-pyrazol-3-yl)methoxy)methyl)-1-cyclohexyl-1H-1,2,3-triazole (6g) was the most potent compound of the series, which showed a MIC of 3.13 ?g/mL. The cytotoxicity study of active anti-TB compounds on normal Vero cells revealed that the compounds are non-toxic with a high selectivity index (>37). Most of the pyrazole-1,2,3-triazole derivatives with a 4-chlorophenyl substitution at position-5 of the pyrazole ring showed a better anti-TB activity than the corresponding 4-bromophenyl or 4-methoxyphenyl substituted derivatives. The target compounds were also evaluated for their in vitro antibacterial activity and six compounds (6a, 6c, 6d, 6e, 6l, and 6w) showed promising inhibition activity against four tested strains. Springer Science+Business Media Dordrecht 2015.