Two routes to [11C-carbonyl]organo-isocyanates utilizing [11C]phosgene ([11C]organo-isocyanates from [11C]phosgene)

Abstract Two generic radiosynthetic routes for the preparation of [ 11 C- carbonyl ]isocyanates have been developed. Reaction of N -organo-sulfinylamines; RNSO, (R = Me, Et, allyl, cyclohexyl and phenyl) with [ 11 C]phosgene gave the corresponding [ 11 C- carbonyl ]isocyanates in good radiochemical yield (53–68%) from [ 11 C]phosgene (decay corrected) in ca 16 min from EOB. Alternatively, the reaction of [ 11 C]phosgene with N,N ′-organo-ureas; (RNH) 2 CO, (R = Me, Et, Pr and phenyl) also gave the corresponding [ 11 C- carbonyl ]isocyanates in moderate radiochemical yield (9–37%) from [ 11 C]phosgene (decay corrected) in ca 16 min from EOB. For identification, the [ 11 C- carbonyl ]organo-isocyanates were derivatized with 1-(2-methoxyphenyl)piperazine in situ to [ 11 C- carbonyl ]carboxamides and the position of radiolabelling in the carbonyl group confirmed by [ 11/13 C]co-labeling and subsequent carbon-13 NMR spectroscopy.