POLYSTYRENE SUPPORTED PYRAZOLINIUM CR(VI) REAGENTS - PREPARATION AND USE IN SYNTHETIC ORGANIC-CHEMISTRY

Divinylbenzene (DVB) and ethyleneglycol dimethacrylate (EGDMA) crossli nked polystyrenes (2%) were functionalized to generate pyrazolinium ch romate, chlorochromate and pyrazole-CrO3 complex functionalities. Thes e were found to oxidize primary and secondary alcohols to the correspo nding carbonyl compounds in high yields. The influence of solvent, tem perature, catalyst and molar excess of the reagent in these oxidation reactions was investigated to find out the optimum conditions for effe ctive oxidation reactions. EGDMA crosslinked polystyrene supported rea gents showed higher reactivity in terms of functional group capacity a nd percentage yield. Also, chlorochromate reagent was found to be very efficient in oxidizing alcohols to carbonyl compounds. The spent poly meric reagent after the oxidation step can be easily removed by filtra tion and can be regenerated many times. (C) 1998 SCI.