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Copper catalyzed radioiodination of 3‐iodotyrosine and 4‐iodophenyl alanine
Author(s) -
Farah K.,
Farouk N.
Publication year - 1997
Publication title -
journal of labelled compounds and radiopharmaceuticals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.432
H-Index - 47
eISSN - 1099-1344
pISSN - 0362-4803
DOI - 10.1002/(sici)1099-1344(199711)39:11<915::aid-jlcr42>3.0.co;2-o
Subject(s) - chemistry , catalysis , yield (engineering) , ascorbic acid , copper , labelling , solvent , medicinal chemistry , iodine , chloride , substrate (aquarium) , sodium , inorganic chemistry , nuclear chemistry , activation energy , organic chemistry , oceanography , biochemistry , materials science , food science , metallurgy , geology
The factors affecting the yield of the copper catalyzed labelling of 3‐iodotyrosine and 4‐iodophenyl alanine such as pH of the medium, catalyst and substrate concentrations and solvent effects are described. The reaction is assumed to take place via an intermediate organo‐copper complex which favours the exchange between radioiodine and the inactive iodine in the iodocompound. The reducing agents ascorbic acid, stannous chloride or sodium metabisulphite are added to the cuprous chloride catalyzed reaction to prevent the oxidation of Cu (I) to Cu (II) in order to decrease side products formation and improve the labelling yield. Kinetics indicated a second order reaction with an activation energy of 9.6 Kcal/mole for 3‐iodotyrosine and 12.2 Kcal/mole for 4‐iodophenyl alanine. The stronger 4‐iodophenyl C‐I bond favours para‐iodination in the preparation of radioiodinated monoclonal antibodies. © 1997 John Wiley & Sons, Ltd.