@article { ISI:000267625000020, title = {Hydroesterification of 2-vinyl-6-methoxynaphthalene using palladium complexes containing chelating nitrogen ligands}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {307}, number = {1-2}, year = {2009}, month = {JUL}, pages = {134-141}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Hydroesterification of 2-vinyl-6-methoxynaphthalene (VMN) to methyl ester of 6-methoxy naphthyl propionic acid (ester of naproxen) has been investigated using palladium complexes containing the chelating N(boolean AND)O and N(boolean AND)N ligands (pyridine-2-carboxylate, 2-acetylpyridine, 2-pyridine-carboxaldehyde, and bipyridine) as catalysts. Palladium complex containing 2-acetylpyridine as the ligand was found to be superior to other Pd-complexes. Both acid and halide promoters were necessary for high activity and selectivity. As an acid promoter, benzenesulfonic acid was found to be more effective compared to p-toluenesulfonic acid. Formation of ether 2-methoxy-6-(1-methoxyethyl)naphthalene and a polymer of VMN was observed in all the reactions. It was observed that active catalytic species generated during carbonylation reaction was responsible for the polymer formation. The effect of various parameters such as solvents, CO pressure, and alcohols on the catalytic activity as well as the selectivity was investigated. The turnover frequency using the complex Pd(acpy)(PPh(3))(OTs)(2) (acpy = 2-acetylpyridine) catalyst was found to be 42 h(-1), which is the highest for the hydroesterification of VMN. (C) 2009 Elsevier B.V. All rights reserved.

}, keywords = {Carbonylation, Hydroesterification, Naproxen, Palladium complex, Polymer of VMN, Promoters}, issn = {1381-1169}, doi = {10.1016/j.molcata.2009.03.021}, author = {Atla, Shashi B. and Kelkar, Ashutosh A. and Chaudhari, Raghunath V.} } @article { ISI:000300474900013, title = {Probing influence of mesophasic transformation on performance of self-emulsifying system: effect of ion}, journal = {Molecular Pharmaceutics}, volume = {9}, number = {2}, year = {2012}, month = {FEB}, pages = {318-324}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Self-emulsifying systems are mixtures of oils and surfactants, ideally isotropic, sometimes including cosolvents, which emulsify under conditions of gentle agitation, similar to those which would be encountered in the gastrointestinal tract. The process of self-emulsification has remained the center of attraction for most researchers. Controlled hydration of self-emulsifying systems shows formation of an intermediate gel phase which upon rupture forms an emulsion. Current work was undertaken to understand and explore the microstructural properties of intermediate gel phase which are believed to influence the performance (droplet size) of the final formulation. The effect of additives on microstructural properties of intermediate gel phase has also been investigated. Microstructural elucidation of hydrated samples of intermediate regimes was done by using techniques such as small angle X-ray scattering, differential scanning calorimetry and rheology. Samples from intermediate regimes showed formation of local lamellar structure which swelled with hydration. In the present work, the effect of addition of salt form of naproxen (sodium and potassium) and naproxen (base) on microstructural properties of intermediate regimes was investigated. Systems containing naproxen salts formed larger droplets whereas naproxen base formed smaller ones. Microstructural properties of intermediate lamellar structures were well correlated with performance of the final formulation. The current studies indicate that by controlling the properties of intermediate regimes optimized formulations with desired performance can be tailor-made.

}, keywords = {emulsion, lamellar structure, liquid crystal, Microstructure, Naproxen, self-emulsifying system}, issn = {1543-8384}, doi = {10.1021/mp200541r}, author = {Patil, Sharvil S. and Venugopal, Edakkal and Bhat, Suresh K. and Mahadik, Kakasaheb R. and Paradkar, Anant R.} } @article { ISI:000344439400007, title = {Regioselective acylation of 2-methoxy naphthalene catalyzed by supported 12-phosphotungstic acid}, journal = {Applied Catalysis A-General}, volume = {486}, year = {2014}, month = {SEP}, pages = {55-61}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

12-Phosphotungstic acid supported on silica gel, zirconium sulfate, and a combination of silica gel and zirconium sulfate (50\% w/w) were employed as solid acid catalysts for regioselective acylation of 2-methoxynaphtalene with acetic anhydride. 1-(6-Methoxynaphthalen-2-yl)ethanone (2,6-AMN), a commercially important intermediate for production of Naproxen, was obtained with excellent selectivity (\>98\%) at 67-68\% conversion using 12-phosphotungstic acid supported on silica gel 20\% (w/w) in refluxing tetrachloroethane. The unreacted starting material can be easily separated from the product by a simple crystallization from nonane. (C) 2014 Elsevier B.V. All rights reserved.

}, keywords = {Acylation, Naproxen, Phosphotungstic acid, Silica gel, Supported, Zirconium sulfate}, issn = {0926-860X}, doi = {10.1016/j.apcata.2014.08.026}, author = {Kumaraguru, Thenkrishnan and Devi, Ayala Vedamayee and Siddaiah, Vidavalur and Rajdeo, Kishor and Fadnavis, Nitin W.} }