Yogesh P. Patil

Cesium carbonate catalyzed efficient synthesis of quinazoline-2,4(1H,3H)-diones using carbon dioxide and 2-aminobenzonitriles

Abstract An efficient protocol for the synthesis of quinazoline-2,4(1H,3H)-diones derivatives from 2-aminobenzonitriles with carbon dioxide using catalytic amount of cesium carbonate has been developed. 6,7-Dimethoxyquinazoline-2,4(1H,3H)-dione, which is one of the key intermediate for the synthesis of several drugs (Prazosin, Bunazosin and Doxazosin) was synthesized. The effect of different reaction parameters like influences of bases, solvent, temperature, CO2 pressure and reaction time were investigated for the title reaction.

Improved activity and stability of Rhizopus oryzae lipase via immobilization for citronellol ester synthesis in supercritical carbon dioxide.

In present work, Rhizopus oryzae lipase immobilized on a film prepared using blend of hydroxylpropyl methyl cellulose (HPMC) and polyvinyl alcohol (PVA) was investigated for synthesis of citronellol esters with supercritical carbon dioxide (Sc-CO(2)) as a reaction medium. The transesterification reaction was optimized for various reaction parameters like effect of molar ratio, acyl donor, time, temperature, enzyme concentration, effect of pressure and co-solvent to achieve the maximum yield of desired product. The results obtained signify remarkable increment (about eightfold) in the yield of citronellol acetate (91%) as compared to that of free lipase (11%) in Sc-CO(2). The developed biocatalytic methodology provides a substantial advantage of low biocatalyst loading (1.5%, w/v), lower reaction temperature (45°C) and lower pressure (8 MPa) as compared to previous reports. The immobilization method has significantly enhanced the operational stability of lipase for ester synthesis under Sc-CO(2) conditions. The developed methodology was successfully applied for synthesis of three different industrially important citronellol esters namely citronellol acetate (91%), citronellol butyrate (98%), citronellol laurate (99%) with excellent yields using vinyl esters as acyl donor under Sc-CO(2) conditions. In addition, the immobilized biocatalyst was effectively recycled for three consecutive recycles.

Ionic Liquid : An Efficient and Recyclable Catalyst for the Synthesis of 1-Amidoalkyl-2-naphthols and 1-Carbamatoalkyl-2-naphthols Under Solvent-Free Conditions

Abstract A simple and efficient protocol for the one-pot synthesis of 1-amidoalkyl-2-naphthols and novel 1-carbamatoalkyl-2-naphthols has been described under solvent-free conditions, using N-methyl-2-pyrrolidone hydrogen sulfate as a reusable Brønsted acidic ionic liquid. This methodology has several advantages such as use of a halogen-free ionic liquid , excellent yields, short reaction time, easy workup procedure, and reusable catalyst. GRAPHICAL ABSTRACT

Synthesis of 1,3-Disubstituted Symmetrical/Unsymmetrical Ureas via Cs2CO3-Catalyzed Transamination of Ethylene Carbonate and Primary Amines

Abstract Cs2CO3-catalyzed transamination of primary amines and ethylene carbonate proceeds to form 1,3-disubstituted symmetrical/unsymmetrical ureas in excellent yields. The effect of different reaction parameters such as influences of bases, temperature, and reaction time were investigated for the title reaction.

Pd(OAc)2-Catalyzed Carbonylative Coupling of Aryl Iodide with Ortho-Haloamines in Water

Abstract The carbonylative cross coupling of aryl iodide with ortho-haloaniline to ortho-haloanilide using phosphine-free Pd(OAc)2 catalyst in water as a reaction medium has been studied. The present protocol facilitated the reaction of o-haloanilines with a wide variety of hindered and functionalized aryl iodides, affording good yields of the desired products. The protocol was also extended for the synthesis of benzoxazoles through cyclization of ortho-haloanilide using Cu(acac)2 catalyst. GRAPHICAL ABSTRACT