SYNTHESIS OF YPHENYL-4-PHENYL-3-BUTENYL)-3-PIPERIDINECARBOXYLIC ACID FOR POSITRON EMISSION TOMOGRAPHY OF THE GABA UPTAKE CARRIER

A procedure for labelling the GABA uptake inhibitor yphenyl-4-phenyl-3 -butenyl)-3-piperidinecarboxylic acid (MPB-P acid) with C-11 at the me thoxy position has been developed. The synthesis involves the reaction of [C-11]methyliodide derived from cyclotron produced [C-11]carbon di oxide with yphenyl-4-phenyl-3-butenyl)-3-piperidinecarboxylic acid eth yl ester (HPB-P ester), followed by ester hydrolysis. Purification is done by semi-preparative reversed phase HPLC. About 6.11 GBq (165 mCi) of the chemical and radiochemical pure [C-11]MPB-P acid are obtained 40 min after EOB, with a specific activity of 35 GBq/mu mol (940 mCi/m u mol).