CHANDRAKANT TRIPATHI (RA2011053010028) - Academia.edu (original) (raw)
Papers by CHANDRAKANT TRIPATHI (RA2011053010028)
![Research paper thumbnail of Synthesis, characterization and biological activity of new cyclization products of 3-(4-substituted benzylidene)-2H-pyrido[1,2-a]pyrimidine 2,4-(3H)-diones](https://attachments.academia-assets.com/93372492/thumbnails/1.jpg)
](Journal of Chemical Sciences, 2013
AbstractA method is presented for the synthesis of 4-(substituted phenyl)-3-(3-substituted phenyl... more AbstractA method is presented for the synthesis of 4-(substituted phenyl)-3-(3-substituted phenyl)4H-spiro[isoxazole-5,3′-pyrido[1,2-a]pyrimidine]-2′,4′-dione (3), 3-(4-substituted phenyl)-3H-isoxazole[3, 4-d]pyrido[1,2-a]pyrimidin-4-(3aH)-one (4) and 3-(4-substituted phenyl) 3,3a-dihydropyrazolo[3,4-d]pyrido[1,2-a]pyrimidin-4-(2H)-one (5) which consists of the conversion of 2H-pyrido[1,2-a]pyrimidine-2,4(3H)-dione (1) to chalcones (2) and their 1,3-dipolar cycloaddition with appropriate aldoximes to give spiro compounds and heterocyclization using amines to yield isoxazolines and pyrazolines. All the compounds were screened for their antimicrobial and antitubercular activity. Graphical Abstract1,3-Dipolar cycloaddition of pyrido-pyrimidine chalcones with appropriate aldoximes give spiro compounds; heterocyclization using hydroxylamine or hydrazine to yield isoxazolines or pyrazolines, respectively. All the compounds were then screened for their biological (antimicrobial and antitub...
Indo American Journal of Pharmaceutical Research, 2015
A series of 10 new 1,3-thiazolidin-4-one (3a-3j) were synthesized from different schiff base of N... more A series of 10 new 1,3-thiazolidin-4-one (3a-3j) were synthesized from different schiff base of N-[(1E)-(3-chloro-5,7-dimethyl-2-naphthyl) methylene]aniline (2a-2j) with thioaceticacid. The chemical structures of these compounds were confirmed by means of 1 H NMR, IR and mass analysis. Newly synthesized compounds were screened in vitro for their antimicrobial activity against varieties of bacterial strains such Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and fungi strain Aspergillus niger at 40 µg/mL. The resulted of compounds shows that chloro and flouro substituted 1,3-thiazolidine-4-one derivatives are showing quite well activity as compare to the other functional groups.
Medicinal Chemistry Research, 2012
A series of quinoline-based heterocycles prepared and bioevaluated for their possible antimicrobi... more A series of quinoline-based heterocycles prepared and bioevaluated for their possible antimicrobial activity against a panel of gram-positive bacteria [Staphylococcus aureus (ATCC-9144) and Bacillus subtilis (ATCC-6633)] and gram-negative bacteria [Pseudomonas aeruginosa (ATCC-25615), and Escherichia coli (MTCC-739)], and fungal strains [Candida albicans (ATCC-24433), Aspergillus niger (MTCC-872), and Aspergillus fumigatus (MTCC-343)] by the known methods. All the prepared quinoline derivatives have shown significant antimicrobial activities. Few compounds, viz. 4b, 4c and 4a, 4c proved to be active at low concentrations against Sa and Ca, respectively, while compounds 4a, 6d, and 6b showed milder inhibitory effects against other microbes. The structures of newly synthesized compounds were characterized by elemental analysis, Infrared (IR), 1HNMR, 13C-NMR and Mass-spectroscopy.
1-(4-Substituted phenyl)-3-(substituted)propan-1-(1H-benzo[d]imidazol-2-yl)hydrazines and 1-(4-su... more 1-(4-Substituted phenyl)-3-(substituted)propan-1-(1H-benzo[d]imidazol-2-yl)hydrazines and 1-(4-substituted phenyl)3-(substituted)propan-1-(5H-[1,2,4]triazino[5,6-b]indol-3-yl) hydrazines have been synthesized by the fusion of triazine and benzimidazole derivatives with Mannich bases. The synthesized compounds have been characterized and screened against ITCC 5226 Sclerotium rolfsii and ITCC 0482 Macrophomina phaseolina and MTCC739 Escherichia coli, ATCC6533 Bacillus subtilis, ATCC9144 Staphylococcus aureus, ATCC25619 Pseudomonas aeruginosa and ATCC24433 Candida albicans.
Indian Journal of Chemistry, Nov 7, 2013
Der Pharma Chemica
A series of substituted piperazine salts have been synthesized and tested for antimicrobial activ... more A series of substituted piperazine salts have been synthesized and tested for antimicrobial activity. The antimicrobial activity was tested against Escherichia coli and Bacillus subtilis. The study indicates that some of these derivatives showed significant activity against tested microbes. Based on the reported results, it may be concluded that an electronegative group is very vital in eliciting the desired biological effect.
Antonie van Leeuwenhoek, Jan 30, 2015
Identification of extracellular conductive pilus-like structures (PLS) i.e. microbial nanowires h... more Identification of extracellular conductive pilus-like structures (PLS) i.e. microbial nanowires has spurred great interest among scientists due to their potential applications in the fields of biogeochemistry, bioelectronics, bioremediation etc. Using conductive atomic force microscopy, we identified microbial nanowires in Microcystis aeruginosa PCC 7806 which is an aerobic, photosynthetic microorganism. We also confirmed the earlier finding that Synechocystis sp. PCC 6803 produces microbial nanowires. In contrast to the use of highly instrumented continuous flow reactors for Synechocystis reported earlier, we identified simple and optimum culture conditions which allow increased production of nanowires in both test cyanobacteria. Production of these nanowires in Synechocystis and Microcystis were found to be sensitive to the availability of carbon source and light intensity. These structures seem to be proteinaceous in nature and their diameter was found to be 4.5-7 and 8.5-11 nm i...
Heterocyclic Communications, 2015
Novel spiro derivatives of piperidone 4a–f were synthesized, characterized, and screened against ... more Novel spiro derivatives of piperidone 4a–f were synthesized, characterized, and screened against a panel of different bacterial and fungal strains. The study revealed the potential of these molecules for further development as antimicrobial agents.
Indian journal of experimental biology, 1997
Production of L-phenylacetylcarbinol (L-PAC) through biotransformation of benzaldehyde by free an... more Production of L-phenylacetylcarbinol (L-PAC) through biotransformation of benzaldehyde by free and immobilized cells of the yeast Saccharomyces cerevisiae has been attempted. L-PAC production was found to be maximum (0.4 microliter/ml) when anaerobically grown free cells were used as biocatalyst during aerobic biotransformation for two hours with magnetically stirred bioreactor. Growth under oxygen limited conditions led to accumulation of higher amount of pyruvate decarboxylase enzyme and co-substrate, pyruvate, resulting in higher L-PAC formation. L-PAC yield was low when biotransformations were carried out anaerobically either for aerobically or anaerobically grown free cells. Free cells were found to be more efficient biocatalyst for L-PAC production, as compared with the immobilized cells, with the investigated benzaldehyde concentration (0.3% v/v) and cell density (17.5% w/v). The study has explored and indicated the possibility of optimizing the yield of L-PAC by growing the ...
Research in Microbiology, 2015
Production of nitric oxide (NO) and the presence of NO metabolism genes, nitrous oxide reductase ... more Production of nitric oxide (NO) and the presence of NO metabolism genes, nitrous oxide reductase (nosZ), nitrous oxide reductase regulator (nosR) and nitric oxide reductase (norB) were identified in the plant-associated bacterium (PAB) Azospirillum brasilense SM. NO presence was confirmed in all overexpressing strains, while improvement in the plant growth response of these strains was mediated by increased NO and indole-3-acetic acid (IAA) levels in the strains. Electron microscopy showed random distribution to biofilm, with surface colonization of pleiomorphic Azospirilla. Quantitative IAA estimation highlighted a crucial role of nosR and norBC in regulating IAA biosynthesis. The NO quencher and donor reduced/blocked IAA biosynthesis by all strains, indicating their common regulatory role in IAA biosynthesis. Tryptophan (Trp) and l-Arginine (Arg) showed higher expression of NO genes tested, while in the case of ipdC, only Trp and IAA increased expression, while Arg had no significant effect. The highest nosR expression in SMnosR in the presence of IAA and Trp, along with its 2-fold IAA level, confirmed the relationship of nosR overexpression with Trp in increasing IAA. These results indicate a strong correlation between IAA and NO in A. brasilense SM and suggest the existence of cross-talk or shared signaling mechanisms in these two growth regulators.
European Journal of Chemistry, 2011
Facile synthesis of 3-(1-(4'-(3-chloro-2-(substituted phenyl)-4-oxoazetidin-1yl)biphenyl-4-yl)-5-... more Facile synthesis of 3-(1-(4'-(3-chloro-2-(substituted phenyl)-4-oxoazetidin-1yl)biphenyl-4-yl)-5-oxo-2-phenyl-1H-imidazol-4(5H)-ylidene)indolin-2-ones and 3-(1-(3-chloro-2-(substituted phenyl)-4-oxoazetidin-1-yl)-5-oxo-2-phenyl-1H-imidazol-4(5H)-ylidene)indolin-2-ones: β-Lactam derivatives as antimicrobes
Journal of Fermentation and Bioengineering, 1997
In pharmaceutical industry, l-phenylacetylcarbinol (l-PAC) is used as an intermediate for the pro... more In pharmaceutical industry, l-phenylacetylcarbinol (l-PAC) is used as an intermediate for the production of l-ephedrine hydrochloride—a well known bronchodilator. Certain yeast strains are known to transform benzaldehyde to produce l-PAC with the help of a specific enzyme pyruvate decarboxylase (PDC) and pyruvate. Simultaneously another by-product, benzyl alcohol is also produced by another enzyme alcohol dehydrogenase (ADH). Strains belonging to the
Bioorganic & Medicinal Chemistry, 2010
The synthesis and screening of neutral and cationic, linear and cyclic peptoids (N-alkylglycine p... more The synthesis and screening of neutral and cationic, linear and cyclic peptoids (N-alkylglycine peptidomimetics) is described. Structure-activity relationship studies show that the in vitro activities of the tested peptoids depend on both cyclization and decoration with cationic groups. The most powerful N-lysine cyclopeptoid derivatives showed good antifungal activity against Candida albicans (ATCC90029 and L21) and Candida famata (SA550, Amph B-resistant) and low hemolytic activity. The effects of the cyclic peptoids on membrane permeabilization were evaluated by the propidium iodide exclusion assay.
Antonie van Leeuwenhoek, Jan 11, 2016
Extracellular pili-like structures (PLS) produced by cyanobacteria have been poorly explored. We ... more Extracellular pili-like structures (PLS) produced by cyanobacteria have been poorly explored. We have done detailed topographical and electrical characterisation of PLS in Nostoc punctiforme PCC 73120 using transmission electron microscopy (TEM) and conductive atomic force microscopy (CAFM). TEM analysis showed that N. punctiforme produces two separate types of PLS differing in their length and diameter. The first type of PLS are 6-7.5 nm in diameter and 0.5-2 µm in length (short/thin PLS) while the second type of PLS are ~20-40 nm in diameter and more than 10 µm long (long/thick PLS). This is the first study to report long/thick PLS in N. punctiforme. Electrical characterisation of these two different PLS by CAFM showed that both are electrically conductive and can act as microbial nanowires. This is the first report to show two distinct PLS and also identifies microbial nanowires in N. punctiforme. This study paves the way for more detailed investigation of N. punctiforme nanowire...
Journal of Chemical Sciences, 2013
AbstractA method is presented for the synthesis of 4-(substituted phenyl)-3-(3-substituted phenyl... more AbstractA method is presented for the synthesis of 4-(substituted phenyl)-3-(3-substituted phenyl)4H-spiro[isoxazole-5,3′-pyrido[1,2-a]pyrimidine]-2′,4′-dione (3), 3-(4-substituted phenyl)-3H-isoxazole[3, 4-d]pyrido[1,2-a]pyrimidin-4-(3aH)-one (4) and 3-(4-substituted phenyl) 3,3a-dihydropyrazolo[3,4-d]pyrido[1,2-a]pyrimidin-4-(2H)-one (5) which consists of the conversion of 2H-pyrido[1,2-a]pyrimidine-2,4(3H)-dione (1) to chalcones (2) and their 1,3-dipolar cycloaddition with appropriate aldoximes to give spiro compounds and heterocyclization using amines to yield isoxazolines and pyrazolines. All the compounds were screened for their antimicrobial and antitubercular activity. Graphical Abstract1,3-Dipolar cycloaddition of pyrido-pyrimidine chalcones with appropriate aldoximes give spiro compounds; heterocyclization using hydroxylamine or hydrazine to yield isoxazolines or pyrazolines, respectively. All the compounds were then screened for their biological (antimicrobial and antitub...
Indo American Journal of Pharmaceutical Research, 2015
A series of 10 new 1,3-thiazolidin-4-one (3a-3j) were synthesized from different schiff base of N... more A series of 10 new 1,3-thiazolidin-4-one (3a-3j) were synthesized from different schiff base of N-[(1E)-(3-chloro-5,7-dimethyl-2-naphthyl) methylene]aniline (2a-2j) with thioaceticacid. The chemical structures of these compounds were confirmed by means of 1 H NMR, IR and mass analysis. Newly synthesized compounds were screened in vitro for their antimicrobial activity against varieties of bacterial strains such Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and fungi strain Aspergillus niger at 40 µg/mL. The resulted of compounds shows that chloro and flouro substituted 1,3-thiazolidine-4-one derivatives are showing quite well activity as compare to the other functional groups.
Medicinal Chemistry Research, 2012
A series of quinoline-based heterocycles prepared and bioevaluated for their possible antimicrobi... more A series of quinoline-based heterocycles prepared and bioevaluated for their possible antimicrobial activity against a panel of gram-positive bacteria [Staphylococcus aureus (ATCC-9144) and Bacillus subtilis (ATCC-6633)] and gram-negative bacteria [Pseudomonas aeruginosa (ATCC-25615), and Escherichia coli (MTCC-739)], and fungal strains [Candida albicans (ATCC-24433), Aspergillus niger (MTCC-872), and Aspergillus fumigatus (MTCC-343)] by the known methods. All the prepared quinoline derivatives have shown significant antimicrobial activities. Few compounds, viz. 4b, 4c and 4a, 4c proved to be active at low concentrations against Sa and Ca, respectively, while compounds 4a, 6d, and 6b showed milder inhibitory effects against other microbes. The structures of newly synthesized compounds were characterized by elemental analysis, Infrared (IR), 1HNMR, 13C-NMR and Mass-spectroscopy.
1-(4-Substituted phenyl)-3-(substituted)propan-1-(1H-benzo[d]imidazol-2-yl)hydrazines and 1-(4-su... more 1-(4-Substituted phenyl)-3-(substituted)propan-1-(1H-benzo[d]imidazol-2-yl)hydrazines and 1-(4-substituted phenyl)3-(substituted)propan-1-(5H-[1,2,4]triazino[5,6-b]indol-3-yl) hydrazines have been synthesized by the fusion of triazine and benzimidazole derivatives with Mannich bases. The synthesized compounds have been characterized and screened against ITCC 5226 Sclerotium rolfsii and ITCC 0482 Macrophomina phaseolina and MTCC739 Escherichia coli, ATCC6533 Bacillus subtilis, ATCC9144 Staphylococcus aureus, ATCC25619 Pseudomonas aeruginosa and ATCC24433 Candida albicans.
Indian Journal of Chemistry, Nov 7, 2013
Der Pharma Chemica
A series of substituted piperazine salts have been synthesized and tested for antimicrobial activ... more A series of substituted piperazine salts have been synthesized and tested for antimicrobial activity. The antimicrobial activity was tested against Escherichia coli and Bacillus subtilis. The study indicates that some of these derivatives showed significant activity against tested microbes. Based on the reported results, it may be concluded that an electronegative group is very vital in eliciting the desired biological effect.
Antonie van Leeuwenhoek, Jan 30, 2015
Identification of extracellular conductive pilus-like structures (PLS) i.e. microbial nanowires h... more Identification of extracellular conductive pilus-like structures (PLS) i.e. microbial nanowires has spurred great interest among scientists due to their potential applications in the fields of biogeochemistry, bioelectronics, bioremediation etc. Using conductive atomic force microscopy, we identified microbial nanowires in Microcystis aeruginosa PCC 7806 which is an aerobic, photosynthetic microorganism. We also confirmed the earlier finding that Synechocystis sp. PCC 6803 produces microbial nanowires. In contrast to the use of highly instrumented continuous flow reactors for Synechocystis reported earlier, we identified simple and optimum culture conditions which allow increased production of nanowires in both test cyanobacteria. Production of these nanowires in Synechocystis and Microcystis were found to be sensitive to the availability of carbon source and light intensity. These structures seem to be proteinaceous in nature and their diameter was found to be 4.5-7 and 8.5-11 nm i...
Heterocyclic Communications, 2015
Novel spiro derivatives of piperidone 4a–f were synthesized, characterized, and screened against ... more Novel spiro derivatives of piperidone 4a–f were synthesized, characterized, and screened against a panel of different bacterial and fungal strains. The study revealed the potential of these molecules for further development as antimicrobial agents.
Indian journal of experimental biology, 1997
Production of L-phenylacetylcarbinol (L-PAC) through biotransformation of benzaldehyde by free an... more Production of L-phenylacetylcarbinol (L-PAC) through biotransformation of benzaldehyde by free and immobilized cells of the yeast Saccharomyces cerevisiae has been attempted. L-PAC production was found to be maximum (0.4 microliter/ml) when anaerobically grown free cells were used as biocatalyst during aerobic biotransformation for two hours with magnetically stirred bioreactor. Growth under oxygen limited conditions led to accumulation of higher amount of pyruvate decarboxylase enzyme and co-substrate, pyruvate, resulting in higher L-PAC formation. L-PAC yield was low when biotransformations were carried out anaerobically either for aerobically or anaerobically grown free cells. Free cells were found to be more efficient biocatalyst for L-PAC production, as compared with the immobilized cells, with the investigated benzaldehyde concentration (0.3% v/v) and cell density (17.5% w/v). The study has explored and indicated the possibility of optimizing the yield of L-PAC by growing the ...
Research in Microbiology, 2015
Production of nitric oxide (NO) and the presence of NO metabolism genes, nitrous oxide reductase ... more Production of nitric oxide (NO) and the presence of NO metabolism genes, nitrous oxide reductase (nosZ), nitrous oxide reductase regulator (nosR) and nitric oxide reductase (norB) were identified in the plant-associated bacterium (PAB) Azospirillum brasilense SM. NO presence was confirmed in all overexpressing strains, while improvement in the plant growth response of these strains was mediated by increased NO and indole-3-acetic acid (IAA) levels in the strains. Electron microscopy showed random distribution to biofilm, with surface colonization of pleiomorphic Azospirilla. Quantitative IAA estimation highlighted a crucial role of nosR and norBC in regulating IAA biosynthesis. The NO quencher and donor reduced/blocked IAA biosynthesis by all strains, indicating their common regulatory role in IAA biosynthesis. Tryptophan (Trp) and l-Arginine (Arg) showed higher expression of NO genes tested, while in the case of ipdC, only Trp and IAA increased expression, while Arg had no significant effect. The highest nosR expression in SMnosR in the presence of IAA and Trp, along with its 2-fold IAA level, confirmed the relationship of nosR overexpression with Trp in increasing IAA. These results indicate a strong correlation between IAA and NO in A. brasilense SM and suggest the existence of cross-talk or shared signaling mechanisms in these two growth regulators.
European Journal of Chemistry, 2011
Facile synthesis of 3-(1-(4'-(3-chloro-2-(substituted phenyl)-4-oxoazetidin-1yl)biphenyl-4-yl)-5-... more Facile synthesis of 3-(1-(4'-(3-chloro-2-(substituted phenyl)-4-oxoazetidin-1yl)biphenyl-4-yl)-5-oxo-2-phenyl-1H-imidazol-4(5H)-ylidene)indolin-2-ones and 3-(1-(3-chloro-2-(substituted phenyl)-4-oxoazetidin-1-yl)-5-oxo-2-phenyl-1H-imidazol-4(5H)-ylidene)indolin-2-ones: β-Lactam derivatives as antimicrobes
Journal of Fermentation and Bioengineering, 1997
In pharmaceutical industry, l-phenylacetylcarbinol (l-PAC) is used as an intermediate for the pro... more In pharmaceutical industry, l-phenylacetylcarbinol (l-PAC) is used as an intermediate for the production of l-ephedrine hydrochloride—a well known bronchodilator. Certain yeast strains are known to transform benzaldehyde to produce l-PAC with the help of a specific enzyme pyruvate decarboxylase (PDC) and pyruvate. Simultaneously another by-product, benzyl alcohol is also produced by another enzyme alcohol dehydrogenase (ADH). Strains belonging to the
Bioorganic & Medicinal Chemistry, 2010
The synthesis and screening of neutral and cationic, linear and cyclic peptoids (N-alkylglycine p... more The synthesis and screening of neutral and cationic, linear and cyclic peptoids (N-alkylglycine peptidomimetics) is described. Structure-activity relationship studies show that the in vitro activities of the tested peptoids depend on both cyclization and decoration with cationic groups. The most powerful N-lysine cyclopeptoid derivatives showed good antifungal activity against Candida albicans (ATCC90029 and L21) and Candida famata (SA550, Amph B-resistant) and low hemolytic activity. The effects of the cyclic peptoids on membrane permeabilization were evaluated by the propidium iodide exclusion assay.
Antonie van Leeuwenhoek, Jan 11, 2016
Extracellular pili-like structures (PLS) produced by cyanobacteria have been poorly explored. We ... more Extracellular pili-like structures (PLS) produced by cyanobacteria have been poorly explored. We have done detailed topographical and electrical characterisation of PLS in Nostoc punctiforme PCC 73120 using transmission electron microscopy (TEM) and conductive atomic force microscopy (CAFM). TEM analysis showed that N. punctiforme produces two separate types of PLS differing in their length and diameter. The first type of PLS are 6-7.5 nm in diameter and 0.5-2 µm in length (short/thin PLS) while the second type of PLS are ~20-40 nm in diameter and more than 10 µm long (long/thick PLS). This is the first study to report long/thick PLS in N. punctiforme. Electrical characterisation of these two different PLS by CAFM showed that both are electrically conductive and can act as microbial nanowires. This is the first report to show two distinct PLS and also identifies microbial nanowires in N. punctiforme. This study paves the way for more detailed investigation of N. punctiforme nanowire...