Pranab J. Das

Synthesis of 4-Arylidene-2-Phenyloxazol-5-Ones Using 1:1 Mixture of Al2O3 -H3BO3

Abstract Cyclodehydration-condensation of hippuric acid and arylaldehydes have been carried out using a 1:1 mixture of Al2O3-H3BO3 in the presence of stoichiometric quantity of acetic anhydride to give the target compound in good yield. This procedure can be used to synthesize the 4-alkylidene analogs also.

Solid phase synthesis of N-arylazoindoles

Abstract Diazonium ions have been immobilized onto an ion-exchange resin support and were subsequently reacted with sodioindole in dry tetrahydrofuran to give the N-arylazoindole. The solid phase diazocoupling reaction appears to be the only method for the preparation of the target molecules.

Synthesis of 1-aryl - 3,3-disubstituted triazenes on ion-exchange resin support

Abstract Diazonium ions have been immobilized on a cation exchanger followed by N-coupling on a 2-amine to give the 3,3-disubstituted-1-aryltriazenes as the only product. Reaction is clean and work up procedure simple.

AN EFFICIENT SYNTHESIS OF QUINOXALINES IN WATER MEDIATED BY TETRAETHYLAMMONIUM BROMATE

An efficient environmentally benign condensation of 1,2 diketones and 1,2-diamines for a facile synthesis of quinoxalines was carried out in aqueous medium in the presence of tetraethylammonium bromate. Short reaction time , environmentally benign condition , easy workup and high yield are the special features of this method.

A Convenient Method for the Oxidation of Aromatic Amines to Nitro Compounds Using Tetra‐n‐alkylammonium Bromates

Abstract Tetra‐n‐propyl and tetra‐n‐butylammonium bromates were used for the oxidation of a variety of aromatic amines to nitro compounds. Reaction condition and recovery simple and yield of products high.

Secondary amine based ionic liquid: an efficient catalyst for solvent free one pot synthesis of xanthenes and benzoxanthenes

Ionic liquids (IL) prepared from dialkylamines and concentrated sulphuric acid were used in an operationally simple, cost effective, efficient and environmentally benign synthesis of xanthenes and benzoxanthenes. Three ILs were screened for their efficiency as promoter of the synthesis. Results indicate di-n-propylammoniumhydrogensulphate to be the most efficient IL. Product recovery is simple and the IL could be recovered for reuse.

Tetra-n-alkylammonium bromates—new and efficient reagents for deoximation

Tetra-n-alkylammonium bromates were prepared from the corresponding bromides for the first time and were used for deoximation of oximes to the corresponding carbonyl compounds.

Bromate Exchange Resin as an Oxidizing Agent in Organic Synthesis

Abstract Bromate exchange resin has been prepared by a simple elution technique and used for the oxidation of aromatic aldehydes to the carboxylic acids. Oxidation is carried out under biphasic condition. Work up is simple. Resin immobilized bromate ions have been used for the first time as an oxidizing agent in organic synthesis.

A NEW REAGENT FOR THE CONVENIENT SYNTHESIS OF t-BUTYL ESTERS FROM t-BUTANOL

An alumina-supported reagent has been prepared to synthesize the t-butyl esters from t-butanol. The method requires less time, mild conditions, and involves simplified work-up. Yield of the products is also high.

Microwave mediated solvent free synthesis of formazans catalyzed by simple ionic liquids derived from dialkylammonium salts

A microwave mediated, ionic liquid catalyzed, VOC free and one pot synthesis of formazans was developed. In an alternative procedure, resin immobilized diazonium ions was used as a solid supported reaction for formazan synthesis. The efficiency of both the procedures was examined with respect to yield of product, reduction of reaction time and environmental impact. Products were obtained in a short reaction time and in moderate to high yield. This study was undertaken to find an alternative green protocol for the synthesis of formazans using ionic liquid as catalyst in aqueous media in the absence of corrosive mineral acids, buffered solutions and VOCs.