Synthesis, radioiodination, and biodistribution of some nido- and closo-monocarbon carborane derivatives

Iodination and radioiodination reactions of several anionic nido- and closo-monocarbon carboranes were conducted. Iodinations occurred more rapidly with nido-carboranes than with closo-carboranes. The most rapid iodination and radioiodination reactions occurred with unsubstituted carboranes. C-amino and C-ammonium derivatives did not iodinate under the conditions studied. Both nido- and closo-carboranes with C-NH-acetyl and C-NH-succinyl substituents iodinated, but the nido-carboranes iodinated under milder reaction conditions. Biodistributions of nido-1-succinylamido-[131I]carborane and closo-1-succinylamido-[125I]carborane were similar in mice, but blood clearance of the nido- compound was slower