Prakash Chandran Ramachandran Nair | University of Kerala (original) (raw)
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Papers by Prakash Chandran Ramachandran Nair
European Journal of Organic Chemistry, 2004
Phenethylamines (PEAs) and their structural analogues are of great importance in modern chemistry... more Phenethylamines (PEAs) and their structural analogues are of great importance in modern chemistry, due to their potential for application in molecular recognition processes and targeted drug discovery. Vast numbers of recently synthesized biologically active molecules and ...
Journal of Fluorine Chemistry, 2012
Flexible four armed polypropylenimine tetraamine dendrimer (DAB-Am-4) core linked through urea mo... more Flexible four armed polypropylenimine tetraamine dendrimer (DAB-Am-4) core linked through urea moieties to a chromophore (aza group) gave rise to the colorimetric sensor 1 for fluoride ions, and a fluorophore (naphthyl group) attached to a similar assembly resulted in 2 which showed an excellent association constant with pyrophosphate anions.
Bulletin of the Korean Chemical Society
Three hydroquinone dimethyl ether derivatives have been synthesized and characterized by X-ray di... more Three hydroquinone dimethyl ether derivatives have been synthesized and characterized by X-ray diffraction. The electron donating properties were evaluated by using UV-vis spectroscopy, cyclic voltammetry and by ESR spectroscopy. The microcrystalline cation-radical salts of the three donor molecules were also isolated by using antimony pentachloride, a single electron Lewis acid oxidant.
Tetrahedron, 2008
The alkylation of aryl 3-oxopropanedithioate with a-haloketones under different reaction conditio... more The alkylation of aryl 3-oxopropanedithioate with a-haloketones under different reaction conditions afforded substituted aryl[2-(methylsulfanyl)-4-phenyl-3-thienyl]methanones and [3-aryl-5-(methylsulfanyl)-2-thienyl](phenyl)methanones. The same strategy was extended to 3-amino-1-aryl-3-thioxo-1-propanones to afford aryl[2-amino-4-phenyl-3-thienyl]methanones and ethyl 3-phenyl-5-piperidino-2-thiophene carboxylate.
Organic Letters, 2007
I. Experimental Section All new compounds were fully characterized with standard spectroscopic te... more I. Experimental Section All new compounds were fully characterized with standard spectroscopic techniques. Microanalyses were performed on a Carlo 1102 elemental analysis instrument. 1 H-NMR and 13 C-NMR spectra were performed on a Bruker Avance DPX500 (500 MHz) spectrometer at 298 K. High resolution mass spectra were obtained on a Micromass Platform II mass spectrometer. Fluorescence emission spectra were obtained using RF-5301/PC Spectrofluorophotometer (Shimadzu) at 298 K. Imidazole, 2,3bis(bromomethyl)quinoxaline, and 2,6-bis(bromomethyl)pyridine (Aldrich) were purchased from Aldrich and used as such. Compound 1; 1,1'-[2,3-quinoxalinyldiylbis(methylene)]bis[3-buthyl-1Himidazolium] dihexafluorophosphate The mixture of 1-methylimidazole (0.16 g, 2.0 mmol) and 2,3bis(bromomethyl)quinoxaline in acetonitrile (0.316g, 1.0 mmol) was heated under reflux overnight. After cooling to room temperature, the solvent was evaporated in vacuo. The residue was dissolved in water (1mL) and a saturated solution of NH 4 PF 6 (2mL) was added to the solution. The resulting white precipitate was filtered off and washed with water. The obtained crude product was recrystallised from acetonitrile and ethanol to give 1 as colorless crystals in
The Journal of Organic Chemistry, 2007
Page 1. Chapter 2 Studies on Crystal Structure and Conformation Assisted Photochemical Reactions ... more Page 1. Chapter 2 Studies on Crystal Structure and Conformation Assisted Photochemical Reactions of Bis(cinnamoy1) Ketene Dithioacetals 2.1 Introduction Among functionalized ketene tlithioacetals,' cinnamoyl ketene dithioacetals ...
…, 2008
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a Full Text option. The original article is ...
Org. Lett, 2007
Quinoxaline derivatives (1−4) bearing two imidazolium moieties are found to strongly bind anions ... more Quinoxaline derivatives (1−4) bearing two imidazolium moieties are found to strongly bind anions and show unique charge-transfer fluorescent responses to pyrophosphate and acetate, whereas they show excimer formation with other anions. Anion-binding studies are investigated ...
J. Org. …, 2007
The rational design and synthesis of efficient receptors to selectively recognize biologically an... more The rational design and synthesis of efficient receptors to selectively recognize biologically and environmentally important anion species is an emerging field of supramolecular chemistry. 1 Both fluorogenic 2,3 and chromogenic 4 anion receptors have attracted a considerable ...
Chemical …, 2002
The conformational change induced by the introduction of a ketenedithioacetal moiety at C-4 of 1,... more The conformational change induced by the introduction of a ketenedithioacetal moiety at C-4 of 1,7-substituted-1,6-hep-tadiene-3,5-diones results in favorable spatial relationships between the alkenoyl groups to effect efficient intra-molecular cycloadditions: irradiation of bis( ...
European Journal of …, 2004
Phenethylamines (PEAs) and their structural analogues are of great importance in modern chemistry... more Phenethylamines (PEAs) and their structural analogues are of great importance in modern chemistry, due to their potential for application in molecular recognition processes and targeted drug discovery. Vast numbers of recently synthesized biologically active molecules and ...
European Journal of Organic Chemistry, 2004
Phenethylamines (PEAs) and their structural analogues are of great importance in modern chemistry... more Phenethylamines (PEAs) and their structural analogues are of great importance in modern chemistry, due to their potential for application in molecular recognition processes and targeted drug discovery. Vast numbers of recently synthesized biologically active molecules and ...
Journal of Fluorine Chemistry, 2012
Flexible four armed polypropylenimine tetraamine dendrimer (DAB-Am-4) core linked through urea mo... more Flexible four armed polypropylenimine tetraamine dendrimer (DAB-Am-4) core linked through urea moieties to a chromophore (aza group) gave rise to the colorimetric sensor 1 for fluoride ions, and a fluorophore (naphthyl group) attached to a similar assembly resulted in 2 which showed an excellent association constant with pyrophosphate anions.
Bulletin of the Korean Chemical Society
Three hydroquinone dimethyl ether derivatives have been synthesized and characterized by X-ray di... more Three hydroquinone dimethyl ether derivatives have been synthesized and characterized by X-ray diffraction. The electron donating properties were evaluated by using UV-vis spectroscopy, cyclic voltammetry and by ESR spectroscopy. The microcrystalline cation-radical salts of the three donor molecules were also isolated by using antimony pentachloride, a single electron Lewis acid oxidant.
Tetrahedron, 2008
The alkylation of aryl 3-oxopropanedithioate with a-haloketones under different reaction conditio... more The alkylation of aryl 3-oxopropanedithioate with a-haloketones under different reaction conditions afforded substituted aryl[2-(methylsulfanyl)-4-phenyl-3-thienyl]methanones and [3-aryl-5-(methylsulfanyl)-2-thienyl](phenyl)methanones. The same strategy was extended to 3-amino-1-aryl-3-thioxo-1-propanones to afford aryl[2-amino-4-phenyl-3-thienyl]methanones and ethyl 3-phenyl-5-piperidino-2-thiophene carboxylate.
Organic Letters, 2007
I. Experimental Section All new compounds were fully characterized with standard spectroscopic te... more I. Experimental Section All new compounds were fully characterized with standard spectroscopic techniques. Microanalyses were performed on a Carlo 1102 elemental analysis instrument. 1 H-NMR and 13 C-NMR spectra were performed on a Bruker Avance DPX500 (500 MHz) spectrometer at 298 K. High resolution mass spectra were obtained on a Micromass Platform II mass spectrometer. Fluorescence emission spectra were obtained using RF-5301/PC Spectrofluorophotometer (Shimadzu) at 298 K. Imidazole, 2,3bis(bromomethyl)quinoxaline, and 2,6-bis(bromomethyl)pyridine (Aldrich) were purchased from Aldrich and used as such. Compound 1; 1,1'-[2,3-quinoxalinyldiylbis(methylene)]bis[3-buthyl-1Himidazolium] dihexafluorophosphate The mixture of 1-methylimidazole (0.16 g, 2.0 mmol) and 2,3bis(bromomethyl)quinoxaline in acetonitrile (0.316g, 1.0 mmol) was heated under reflux overnight. After cooling to room temperature, the solvent was evaporated in vacuo. The residue was dissolved in water (1mL) and a saturated solution of NH 4 PF 6 (2mL) was added to the solution. The resulting white precipitate was filtered off and washed with water. The obtained crude product was recrystallised from acetonitrile and ethanol to give 1 as colorless crystals in
The Journal of Organic Chemistry, 2007
Page 1. Chapter 2 Studies on Crystal Structure and Conformation Assisted Photochemical Reactions ... more Page 1. Chapter 2 Studies on Crystal Structure and Conformation Assisted Photochemical Reactions of Bis(cinnamoy1) Ketene Dithioacetals 2.1 Introduction Among functionalized ketene tlithioacetals,' cinnamoyl ketene dithioacetals ...
…, 2008
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a Full Text option. The original article is ...
Org. Lett, 2007
Quinoxaline derivatives (1−4) bearing two imidazolium moieties are found to strongly bind anions ... more Quinoxaline derivatives (1−4) bearing two imidazolium moieties are found to strongly bind anions and show unique charge-transfer fluorescent responses to pyrophosphate and acetate, whereas they show excimer formation with other anions. Anion-binding studies are investigated ...
J. Org. …, 2007
The rational design and synthesis of efficient receptors to selectively recognize biologically an... more The rational design and synthesis of efficient receptors to selectively recognize biologically and environmentally important anion species is an emerging field of supramolecular chemistry. 1 Both fluorogenic 2,3 and chromogenic 4 anion receptors have attracted a considerable ...
Chemical …, 2002
The conformational change induced by the introduction of a ketenedithioacetal moiety at C-4 of 1,... more The conformational change induced by the introduction of a ketenedithioacetal moiety at C-4 of 1,7-substituted-1,6-hep-tadiene-3,5-diones results in favorable spatial relationships between the alkenoyl groups to effect efficient intra-molecular cycloadditions: irradiation of bis( ...
European Journal of …, 2004
Phenethylamines (PEAs) and their structural analogues are of great importance in modern chemistry... more Phenethylamines (PEAs) and their structural analogues are of great importance in modern chemistry, due to their potential for application in molecular recognition processes and targeted drug discovery. Vast numbers of recently synthesized biologically active molecules and ...