Palladium-mediated synthesis of [carbonyl-11C]amides and hydrazides using [11C]carbon monoxide

摘要

Low concentrations of [n11nC]carbon monoxide, a palladium complex, aryl halides and ammonia or hydrazine werenused for the synthesis of five benzamides and seven hydrazides. Some of the selected compounds (e.g. nicotinamidenand benzamide) are biologically active. The reactivity of the bromo- and iodoheteroaryls was studied for similarn11nC-carbonylation reactions. Furthermore, the impact of tetrabutylammonium iodide on the reactivity of 2-bromo-n5-nitrofuran has been investigated. The radiochemical yield of the n11nC-labelled compounds was in the range ofn40–90% and the specific radioactivity was up to 1700 GBq µmolnu00011n. The radiochemical purity of the targetncompounds was determined by analytical HPLC and exceeded 95%. In a typical experiment starting with 7.0 GBqn[n11nC]carbon monoxide, 2.1 GBq of HPLC-purified thiophene-2-[carbonyl-n11nC]carbohydrazide were obtained withinn27 minutes of the start of the carbonylation reaction (75% decay-corrected radiochemical yield). (carbonyl-n13nC)Benzohydrazide was produced to verify the position of the label (δ 165.9 ppm) using n13nC NMR.