ELECTROPHILIC RADIOIODINATION OF TYROSINE DERIVATIVES

A comparative study on the electrophilic radioiodination of L-tyrosine , L-alpha-methyl tyrosine and L-tyrosine methyl ester has been carried out using chloramine-T (CAT) and iodogen as oxidizing agents to gener ate electrophilic radioiodine. Optimization of the radioiodination con ditions has been performed resulting in high labelling yields within s hort reaction times at room temperature. Radiochromatograms also revea led side product impurities at longer reaction time and higher oxidizi ng agent concentration. Maximum yields of 93%, 90% and 78% were obtain ed in case of CAT, while 87%, 88% and 53% were obtained in case of iod ogen for L-3-[I-131] iodotyrosine, L-3-[I-131] iodo-a-methyl tyrosine and L-3-[I-131] iodotyrosine methyl ester respectively.