Dr. Parthiban. P, is currently Associate Professor and Head, Department of Chemistry, PRIST University, Thanjavur, India. Additionally he is serving as Asst. Director of the centre for R
AbstractSimultaneous chiral and chemoseparation of R-(+)-rabeprazole and related (enantio)impurit... more AbstractSimultaneous chiral and chemoseparation of R-(+)-rabeprazole and related (enantio)impurities was achieved on a cellulose tris-(3,5-dichlorophenylcarbamate) stationary phase chemically bonded to silica gel (Chiralpak IC). A gradient elution was applied in the reverse-phase separation mode. The mobile phase consisted of a mixture of acetonitrile and aqueous phosphate buffer at pH 7. The other operational parameters were flow rate of 1 mL min−1, column temperature of 35 °C and ultraviolet (UV) detection at 282 nm. Quantification limits for R-(+)-rabeprazole and the related impurities ranged in the interval of 0.02–0.03 %. Linear response intervals of 0.02–0.66 % were obtained with UV detection. Validation of the proposed method was achieved according to current regulations in force. For better understanding of the R-(+)-rabeprazole impurity profile, (+)-EMS/MS and MS/MS detection were also used.
A new molecule, 3,5-dimethyl-2,6-bis(2,4-dichlorophenyl) piperidin-4-one was synthesized by a mod... more A new molecule, 3,5-dimethyl-2,6-bis(2,4-dichlorophenyl) piperidin-4-one was synthesized by a modified Mannich condensation of 2 moles of 2,4-dichlorobenzaldehyde, 1mole each of 3-pentanone and ammonium acetate (instead of amine in the typical procedure) in ethanol; recrystallized with ethanol to afford the pale yellow powder with 56% yield. The molecule was characterized by IR, 1H NMR,13C NMR and elemental analysis. Based on the NMR data, it is identified that the molecule exists in a chair conformation with equatorial orientation of all the substituents. Apart, few interesting NMR results are, (i) a broad singlet was observed for the active methine protons at C-3 and C-5, instead of a multiplet, (ii) significant deshielding of the protons at C-2 and C-6 due to the interaction of these protons with chlorine atoms at ortho positions (2’a and 6’a) of the phenyl groups; leads to restricted rotation of the phenyl groups as well, (iii) The ortho protons of 2,4-dichloro phenyl (2’e and 6...
Journal of Chemical and Pharmaceutical Sciences, 2018
Synthesis of new molecules with bio-potent piperidine/piperidone skeleton and their stereochemica... more Synthesis of new molecules with bio-potent piperidine/piperidone skeleton and their stereochemical investigation are important in the field of medicinal chemistry due to the presence of piperidine/piperidone skeleton as a building block in numerous naturally occurring alkaloids and biologically active compounds. Since the stereochemistry of any molecules plays vital role in eliciting their biological response, it is very important to ascertain the configuration and conformation of the molecules that obtained for the biological screening. Hence, it was planned to synthesis some polyfunctionalized piperidin-4-ones as new bio-active molecules to establish their stereochemistry. Particularly, the synthesis has been targeted to polyfunctionalized 2,6-bis(polymethoxyphenyl)piperidin-4-ones in view of the fact that the methoxy groups are responsible for various biological actions including antioxidant property. Thus, the target molecules 3,5-dimethyl-2,6-bis(3,4-dimethoxyphenyl)piperidin-4-one (1) and 3,5-dimethyl-2,6bis(2,5-dimethoxyphenyl)piperidin-4-one (2) were achieved as single isomer by modified Mannich condensations. Identification and characterization of the synthesized molecules were made by analytical (TLC, melting point, elemental analyses) and spectral (IR and NMR) studies. The NMR spectral studies, particularly, the proton NMR spectral data were very useful to determine the configuration and conformation of the new molecules 1 and 2. Accordingly, both of them exist in chair conformation with equatorial orientations of methyl groups on the active methylene centers (C-3 and C-5) and polymethoxyphenyl groups on both sides of the secondary amine (C-2 and C-6). Another interesting observation from the proton NMR is, the ortho substitution on 1 (i.e., molecule 2) cause a significant deshielding on benzylic (H-2a/H-6a) and ortho protons, and a minor deshielding on methinic protons (H-3a/H-5a), whereas, all the above three signals appear as broad singlet due to the restricted rotation by the interaction of ortho methoxy groups with the methyl groups at C-3 and C-5.
Variously substituted 3-azabicyclo [3.3. 1] nonan-9-ones viz, 2, 4-diaryl-3-azabicyclo [3.3. 1] n... more Variously substituted 3-azabicyclo [3.3. 1] nonan-9-ones viz, 2, 4-diaryl-3-azabicyclo [3.3. 1] nonan-9-ones, 2, 4-diaryl-1-methyl-3-azabicyclo [3.3. 1] nonan-9-ones and 2, 4-diaryl-7-methyl-3-azabicyclo [3.3. 1] nonan-9-ones were conveniently synthesized by a modified and an optimized one-pot Mannich condensation of cyclohexanones, benzaldehydes and ammonium acetate in 1: 2: 1.5 M ratio. All the synthesized bicycles were examined by their physical and spectral (IR, HR-MS, 1H NMR and 13C NMR) techniques. In order to ...
Acta Crystallographica Section E Structure Reports Online, 2013
The title compound, C31H24F4N2O, exists in a chair–boat conformation with an equatorial orientati... more The title compound, C31H24F4N2O, exists in a chair–boat conformation with an equatorial orientation of the 2-fluorophenyl groups on both sides of the secondary amino group of the chair form. The benzene rings in the `chair' part are inclined to each other at 19.4 (1)°, while the equivalent angle between the benzene rings in the `boat' part is 75.6 (1)°. One F atom was treated as disordered over two positions in a 0.838 (4):0.162 (4) ratio. In the crystal, N—H...O hydrogen bonds link the molecules into chains along [001] and these chains are held togetherviaweak N—H...F and C—H...F interactions.
Acta Crystallographica Section E Structure Reports Online, 2010
In the title compound, C 21 H 20 Cl 3 NO 2 , the piperidin-4-one ring adopts a boat conformation.... more In the title compound, C 21 H 20 Cl 3 NO 2 , the piperidin-4-one ring adopts a boat conformation. The two 2-chlorophenyl groups are approximately perpendicular to each other, making a dihedral angle of 74.07 (8) .
Caffeine is a bitter, white crystalline purine derivative that closely related to adenine and gua... more Caffeine is a bitter, white crystalline purine derivative that closely related to adenine and guanine. Caffeine is used to reduce physical fatigue and to prevent or treat drowsiness. It produces increased wakefulness and focus, improves thought-processing, and better general body coordination. The amount of caffeine needed to produce these effects varies from person to person, depending on body size and degree of tolerance. Hence, it is of importance to estimate the quantity of caffeine present in various types of tea and coffee products. Accordingly, a simple and efficient approach has been done on a variety of tea samples from various places in the southern region of India to understand the quantity of caffeine with respect to the region of cultivation. Among the samples from Nilgiris/ Valparai/ Kodaikanal of Tamilnadu, Munnar of Kerala, and Coorg of Karnataka, the Garden green tea from Coorg (Sample 8 ) is the best in terms of caffeine quantity (2.37%).
2014 International Conference on Science Engineering and Management Research (ICSEMR), 2014
Benzimidazole derivatives are wide interest because of their biological activity and clinical use... more Benzimidazole derivatives are wide interest because of their biological activity and clinical uses. Short and simple method was developed to control the "carry over impurity" in 5-methhoxy-2-mercaptobenzimidazole. This benzimidazole derivative was used in various drug substance syntheses. The proposed method was short (20 min run time) and validated as per the standard validation guidelines. Chromatographic separation was achieved in Inertsil ODS-3V (150mm long, 4.6 inner diameter and 5μm particle size). Compare to other C-18 columns, Inertsil column showed symmetry peak. Mobile phase A was 4.5 pH buffer of perchloric acid in water, and mobile phase B was acetonitrile that were used as eluent in gradient mode. The gradient program as follows: time (min)/A (v/v):B (v/v); T0.0/75:25; T5.0/75:25; T12.0/55:45; T15.0/75:25, T20.0(/75:25; injection volume was 5μ1. Methanol : water (3:7) was used as a diluent. Sample preparation was 250μg/ml. Column temperature was set at 35°C. UV detection was made 302 nm. Linear response was observed between concentrations against response. LOQ, LOD of the 5-M-2-MB, and 2-MB are 0.015%, 0.010%, 0.006% and 0.005% respectively. Recovery percentage of 2-MB was observed 107 and 106 with good precision of <; 2% RSD.
Acta crystallographica. Section E, Structure reports online, 2014
The title compound, C25H29Cl2NO, which is a chloro analog of 2,4-bis-(2-bromo-phen-yl)-7-(tert-pe... more The title compound, C25H29Cl2NO, which is a chloro analog of 2,4-bis-(2-bromo-phen-yl)-7-(tert-pent-yl)-3-aza-bicyclo-[3.3.1]nonan-9-one [Park, Ramkumar & Parthiban (2012). Acta Cryst. E68, o2946], exists in a twin-chair conformation with an equatorial orientation of the 2-chloro-phenyl groups. The tert-pentyl group on the cyclo-hexa-none adopts an exocyclic equatorial position and is disordered between two orientations in a ratio 0.520 (8):0.480 (8). The crystal packing shows no directional contacts beyond van der Waals contacts.
Acta Crystallographica Section E Structure Reports Online, 2008
The title compound, C20H19F2NO, exhibits a chair–chair conformation, with the aryl groups in the ... more The title compound, C20H19F2NO, exhibits a chair–chair conformation, with the aryl groups in the heterocycle in equatorial orientations and oriented at an angle of 33.35 (3)° to one another. A crystallographic mirror plane, passing through the N atom, the C and O atoms of the carbonyl group and the C atom in the 7-position, bisects the molecule. The molecular structure is stabilized by one C—H...N interaction and the crystal structure is stabilized by a weak C—H...π interaction.
The maximization of a networks lifetime is an important part of research in the present scenario.... more The maximization of a networks lifetime is an important part of research in the present scenario. In an ad hoc network, the topology of network changes frequently due to the mobility of mobile nodes where the communication is possible without any network infrastructure. Mobile nodes have limited energy resources so that the energy efficient routing should be provided which increases the life time of the network. The existing routing mechanisms do not consider energy of nodes for data transmission. In this paper the data transfer from source to destination is based on the minimum hop count and residual energy of the mobile nodes. The analysis is carried out by using the network simulator. The simulation results shows that the proposed work provides an energy efficient routing in ad hoc networks.
Acta Crystallographica Section E Structure Reports Online, 2009
The title compound, C 20 H 19 F 2 NO, exists in a twin-chair conformation with an equatorial orie... more The title compound, C 20 H 19 F 2 NO, exists in a twin-chair conformation with an equatorial orientation of the two 2fluorophenyl groups on both sides of the secondary amine group. The benzene rings are orientated at an angle of 25.68 (4) with respect to one another and the F atoms point upwards (towards the carbonyl group). The crystal is stabilized by an intermolecular N-HÁ Á Á interaction. organic compounds o1596 Parthiban et al.
AbstractSimultaneous chiral and chemoseparation of R-(+)-rabeprazole and related (enantio)impurit... more AbstractSimultaneous chiral and chemoseparation of R-(+)-rabeprazole and related (enantio)impurities was achieved on a cellulose tris-(3,5-dichlorophenylcarbamate) stationary phase chemically bonded to silica gel (Chiralpak IC). A gradient elution was applied in the reverse-phase separation mode. The mobile phase consisted of a mixture of acetonitrile and aqueous phosphate buffer at pH 7. The other operational parameters were flow rate of 1 mL min−1, column temperature of 35 °C and ultraviolet (UV) detection at 282 nm. Quantification limits for R-(+)-rabeprazole and the related impurities ranged in the interval of 0.02–0.03 %. Linear response intervals of 0.02–0.66 % were obtained with UV detection. Validation of the proposed method was achieved according to current regulations in force. For better understanding of the R-(+)-rabeprazole impurity profile, (+)-EMS/MS and MS/MS detection were also used.
A new molecule, 3,5-dimethyl-2,6-bis(2,4-dichlorophenyl) piperidin-4-one was synthesized by a mod... more A new molecule, 3,5-dimethyl-2,6-bis(2,4-dichlorophenyl) piperidin-4-one was synthesized by a modified Mannich condensation of 2 moles of 2,4-dichlorobenzaldehyde, 1mole each of 3-pentanone and ammonium acetate (instead of amine in the typical procedure) in ethanol; recrystallized with ethanol to afford the pale yellow powder with 56% yield. The molecule was characterized by IR, 1H NMR,13C NMR and elemental analysis. Based on the NMR data, it is identified that the molecule exists in a chair conformation with equatorial orientation of all the substituents. Apart, few interesting NMR results are, (i) a broad singlet was observed for the active methine protons at C-3 and C-5, instead of a multiplet, (ii) significant deshielding of the protons at C-2 and C-6 due to the interaction of these protons with chlorine atoms at ortho positions (2’a and 6’a) of the phenyl groups; leads to restricted rotation of the phenyl groups as well, (iii) The ortho protons of 2,4-dichloro phenyl (2’e and 6...
Journal of Chemical and Pharmaceutical Sciences, 2018
Synthesis of new molecules with bio-potent piperidine/piperidone skeleton and their stereochemica... more Synthesis of new molecules with bio-potent piperidine/piperidone skeleton and their stereochemical investigation are important in the field of medicinal chemistry due to the presence of piperidine/piperidone skeleton as a building block in numerous naturally occurring alkaloids and biologically active compounds. Since the stereochemistry of any molecules plays vital role in eliciting their biological response, it is very important to ascertain the configuration and conformation of the molecules that obtained for the biological screening. Hence, it was planned to synthesis some polyfunctionalized piperidin-4-ones as new bio-active molecules to establish their stereochemistry. Particularly, the synthesis has been targeted to polyfunctionalized 2,6-bis(polymethoxyphenyl)piperidin-4-ones in view of the fact that the methoxy groups are responsible for various biological actions including antioxidant property. Thus, the target molecules 3,5-dimethyl-2,6-bis(3,4-dimethoxyphenyl)piperidin-4-one (1) and 3,5-dimethyl-2,6bis(2,5-dimethoxyphenyl)piperidin-4-one (2) were achieved as single isomer by modified Mannich condensations. Identification and characterization of the synthesized molecules were made by analytical (TLC, melting point, elemental analyses) and spectral (IR and NMR) studies. The NMR spectral studies, particularly, the proton NMR spectral data were very useful to determine the configuration and conformation of the new molecules 1 and 2. Accordingly, both of them exist in chair conformation with equatorial orientations of methyl groups on the active methylene centers (C-3 and C-5) and polymethoxyphenyl groups on both sides of the secondary amine (C-2 and C-6). Another interesting observation from the proton NMR is, the ortho substitution on 1 (i.e., molecule 2) cause a significant deshielding on benzylic (H-2a/H-6a) and ortho protons, and a minor deshielding on methinic protons (H-3a/H-5a), whereas, all the above three signals appear as broad singlet due to the restricted rotation by the interaction of ortho methoxy groups with the methyl groups at C-3 and C-5.
Variously substituted 3-azabicyclo [3.3. 1] nonan-9-ones viz, 2, 4-diaryl-3-azabicyclo [3.3. 1] n... more Variously substituted 3-azabicyclo [3.3. 1] nonan-9-ones viz, 2, 4-diaryl-3-azabicyclo [3.3. 1] nonan-9-ones, 2, 4-diaryl-1-methyl-3-azabicyclo [3.3. 1] nonan-9-ones and 2, 4-diaryl-7-methyl-3-azabicyclo [3.3. 1] nonan-9-ones were conveniently synthesized by a modified and an optimized one-pot Mannich condensation of cyclohexanones, benzaldehydes and ammonium acetate in 1: 2: 1.5 M ratio. All the synthesized bicycles were examined by their physical and spectral (IR, HR-MS, 1H NMR and 13C NMR) techniques. In order to ...
Acta Crystallographica Section E Structure Reports Online, 2013
The title compound, C31H24F4N2O, exists in a chair–boat conformation with an equatorial orientati... more The title compound, C31H24F4N2O, exists in a chair–boat conformation with an equatorial orientation of the 2-fluorophenyl groups on both sides of the secondary amino group of the chair form. The benzene rings in the `chair' part are inclined to each other at 19.4 (1)°, while the equivalent angle between the benzene rings in the `boat' part is 75.6 (1)°. One F atom was treated as disordered over two positions in a 0.838 (4):0.162 (4) ratio. In the crystal, N—H...O hydrogen bonds link the molecules into chains along [001] and these chains are held togetherviaweak N—H...F and C—H...F interactions.
Acta Crystallographica Section E Structure Reports Online, 2010
In the title compound, C 21 H 20 Cl 3 NO 2 , the piperidin-4-one ring adopts a boat conformation.... more In the title compound, C 21 H 20 Cl 3 NO 2 , the piperidin-4-one ring adopts a boat conformation. The two 2-chlorophenyl groups are approximately perpendicular to each other, making a dihedral angle of 74.07 (8) .
Caffeine is a bitter, white crystalline purine derivative that closely related to adenine and gua... more Caffeine is a bitter, white crystalline purine derivative that closely related to adenine and guanine. Caffeine is used to reduce physical fatigue and to prevent or treat drowsiness. It produces increased wakefulness and focus, improves thought-processing, and better general body coordination. The amount of caffeine needed to produce these effects varies from person to person, depending on body size and degree of tolerance. Hence, it is of importance to estimate the quantity of caffeine present in various types of tea and coffee products. Accordingly, a simple and efficient approach has been done on a variety of tea samples from various places in the southern region of India to understand the quantity of caffeine with respect to the region of cultivation. Among the samples from Nilgiris/ Valparai/ Kodaikanal of Tamilnadu, Munnar of Kerala, and Coorg of Karnataka, the Garden green tea from Coorg (Sample 8 ) is the best in terms of caffeine quantity (2.37%).
2014 International Conference on Science Engineering and Management Research (ICSEMR), 2014
Benzimidazole derivatives are wide interest because of their biological activity and clinical use... more Benzimidazole derivatives are wide interest because of their biological activity and clinical uses. Short and simple method was developed to control the "carry over impurity" in 5-methhoxy-2-mercaptobenzimidazole. This benzimidazole derivative was used in various drug substance syntheses. The proposed method was short (20 min run time) and validated as per the standard validation guidelines. Chromatographic separation was achieved in Inertsil ODS-3V (150mm long, 4.6 inner diameter and 5μm particle size). Compare to other C-18 columns, Inertsil column showed symmetry peak. Mobile phase A was 4.5 pH buffer of perchloric acid in water, and mobile phase B was acetonitrile that were used as eluent in gradient mode. The gradient program as follows: time (min)/A (v/v):B (v/v); T0.0/75:25; T5.0/75:25; T12.0/55:45; T15.0/75:25, T20.0(/75:25; injection volume was 5μ1. Methanol : water (3:7) was used as a diluent. Sample preparation was 250μg/ml. Column temperature was set at 35°C. UV detection was made 302 nm. Linear response was observed between concentrations against response. LOQ, LOD of the 5-M-2-MB, and 2-MB are 0.015%, 0.010%, 0.006% and 0.005% respectively. Recovery percentage of 2-MB was observed 107 and 106 with good precision of <; 2% RSD.
Acta crystallographica. Section E, Structure reports online, 2014
The title compound, C25H29Cl2NO, which is a chloro analog of 2,4-bis-(2-bromo-phen-yl)-7-(tert-pe... more The title compound, C25H29Cl2NO, which is a chloro analog of 2,4-bis-(2-bromo-phen-yl)-7-(tert-pent-yl)-3-aza-bicyclo-[3.3.1]nonan-9-one [Park, Ramkumar & Parthiban (2012). Acta Cryst. E68, o2946], exists in a twin-chair conformation with an equatorial orientation of the 2-chloro-phenyl groups. The tert-pentyl group on the cyclo-hexa-none adopts an exocyclic equatorial position and is disordered between two orientations in a ratio 0.520 (8):0.480 (8). The crystal packing shows no directional contacts beyond van der Waals contacts.
Acta Crystallographica Section E Structure Reports Online, 2008
The title compound, C20H19F2NO, exhibits a chair–chair conformation, with the aryl groups in the ... more The title compound, C20H19F2NO, exhibits a chair–chair conformation, with the aryl groups in the heterocycle in equatorial orientations and oriented at an angle of 33.35 (3)° to one another. A crystallographic mirror plane, passing through the N atom, the C and O atoms of the carbonyl group and the C atom in the 7-position, bisects the molecule. The molecular structure is stabilized by one C—H...N interaction and the crystal structure is stabilized by a weak C—H...π interaction.
The maximization of a networks lifetime is an important part of research in the present scenario.... more The maximization of a networks lifetime is an important part of research in the present scenario. In an ad hoc network, the topology of network changes frequently due to the mobility of mobile nodes where the communication is possible without any network infrastructure. Mobile nodes have limited energy resources so that the energy efficient routing should be provided which increases the life time of the network. The existing routing mechanisms do not consider energy of nodes for data transmission. In this paper the data transfer from source to destination is based on the minimum hop count and residual energy of the mobile nodes. The analysis is carried out by using the network simulator. The simulation results shows that the proposed work provides an energy efficient routing in ad hoc networks.
Acta Crystallographica Section E Structure Reports Online, 2009
The title compound, C 20 H 19 F 2 NO, exists in a twin-chair conformation with an equatorial orie... more The title compound, C 20 H 19 F 2 NO, exists in a twin-chair conformation with an equatorial orientation of the two 2fluorophenyl groups on both sides of the secondary amine group. The benzene rings are orientated at an angle of 25.68 (4) with respect to one another and the F atoms point upwards (towards the carbonyl group). The crystal is stabilized by an intermolecular N-HÁ Á Á interaction. organic compounds o1596 Parthiban et al.
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