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Ponpandian T.,Madurai Kamaraj University | Ponpandian T.,Orchid Chemicals and Pharmaceuticals Ltd | Muthusubramanian S.,Madurai Kamaraj University
Tetrahedron | Year: 2013

This paper describes a new strategy for the stereoselective synthesis of pyrrolizidine and indolizidine based enamino esters and their acyl derivatives from L-proline. The key reaction in this process involves deprotection followed by ring closure of cyclic N-Boc amino-β-ketoesters. Also, the synthesis of 5R,9R- (-)-indolizidine 209D has been accomplished using this protocol. © 2012 Elsevier Ltd. All rights reserved. Source


Rajakumar P.,University of Madras | Padmanabhan R.,Orchid Chemicals and Pharmaceuticals Ltd
Tetrahedron | Year: 2011

A series of mono, tricyclic cyclophane tetraamides and cyclophane sulfonamides have been synthesized and characterized from spectral and XRD studies. All the cyclophane amides form charge transfer (CT) complex with TCNQ. The cyclophane amides show moderate to good anti-inflammatory activity. Some of them were active against Gram positive (Klebsiella pneumonia) and Gram negative (Escherichia coli and Staphylococcus aureus) human pathogens. © 2011 Elsevier Ltd. All rights reserved. Source


Selvaraj S.,SASTRA University | Mohan A.,SASTRA University | Narayanan S.,Orchid Chemicals and Pharmaceuticals Ltd | Sethuraman S.,SASTRA University | Krishnan U.M.,SASTRA University
Journal of Medicinal Chemistry | Year: 2013

The present study investigates dose-dependent effects of trans-resveratrol on the membrane fluidity using planar lipid bilayer and liposome models. The complex admittance plots obtained for the lipid bilayer show that resveratrol below 60 μM preferentially interacts with the polar headgroups at the membrane-electrolyte interface, leading to enhanced membrane admittance and vice versa at higher concentrations (>60 μM). This was confirmed using solid-state 13C and 31P NMR studies and membrane fluidization studies. The localization of resveratrol in the membrane bilayer was found to alter the membrane rigidity, which resulted in a dose-dependent blebbing and lysis of erythrocytes. The protective effect of trans-resveratrol against DPPH also confirms that its localization in the hydrophobic region prevents lipid peroxidation. The cytotoxic effect of resveratrol on a breast cancer cell line also displays a progressive pattern, indicating possible correlation with its membrane rigidifying properties and localization in the lipid bilayer. © 2013 American Chemical Society. Source


Ponpandian T.,Madurai Kamaraj University | Ponpandian T.,Orchid Chemicals and Pharmaceuticals Ltd | Muthusubramanian S.,Madurai Kamaraj University
Tetrahedron Letters | Year: 2012

The efficient synthesis of 2-arylindoles and 6H-isoindolo[2,1-a]indol-6-one through copper catalysed domino sp-sp 2 decarboxylative cross-coupling and subsequent cyclisation reactions of arylpropiolic acids with 2-iodotrifluoroacetanilide has been described. This methodology also demonstrates that indolo[1,2-c]quinazolin-6(5H)-one can be obtained with the elimination of trifluoromethyl anion. © 2012 Elsevier Ltd. All rights reserved. Source


Rajakumar P.,University of Madras | Padmanabhan R.,Orchid Chemicals and Pharmaceuticals Ltd
Tetrahedron Letters | Year: 2010

A series of tricyclic tetraamides have been synthesized and were characterized from spectral and XRD studies. XRD studies revealed that the pyridine-based tricyclic cyclophane amide exists with twisted phenyl rings. All the cyclophane compounds form charge-transfer (CT) complexes with TCNQ. Metal ion complexation studies show that the cyclophane amides are more selective towards Cu(II) ions rather than Ni(II) and Cd(II) ions. © 2010 Elsevier Ltd. All rights reserved. Source

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