title: Palladium-mediated oxidative carbonylation reactions for the synthesis of (11) C-radiolabelled ureas.
abstract: Palladium(II)-mediated oxidative carbonylation reactions have been used to synthesize (11) C-radiolabelled ureas via the coupling of amines with [(11) C]carbon monoxide, in a one-pot process. Following trapping of (11) CO in a solution of copper(I) tris(3,5-dimethylpyrazolyl)borate, homocoupling reactions of primary aliphatic amines proceed in the presence of Pd(PPh3 )2 Cl2 to give the corresponding N,N-disubstituted [(11) C]ureas. Secondary amines do not produce the corresponding N,N,N,N-tetrasubsituted [(11) C]ureas under these conditions. This difference in reactivity allows for the formation of unsymmetrical N,N',N'-trisubstituted [(11) C]ureas using a mixture of a primary amine and a reactive secondary amine. The potential use of this method in positron emission tomography (PET) was demonstrated by the synthesis of the M1 muscarinic acetylcholine receptor radiotracer, [(11) C-carbonyl]GSK1034702.
authors: Institute of Psychiatry, De Crespigny Park, King's College London, London, SE5 8AF, UK; Imanova Ltd., Hammersmith Hospital, Du Cane Road, London, W12 0NN, UK.
authors: Steven
authors: S
authors: Kealey
authors: Stephen M
authors: SM
authors: Husbands
authors: Idriss
authors: I
authors: Bennacef
authors: Antony D
authors: AD
authors: Gee
authors: Jan
authors: J
authors: Passchier
mesh_terms: D001562:Benzimidazoles; D002248:Carbon Monoxide / Q000737:chemistry*; D002250:Carbon Radioisotopes; D002384:Catalysis; D007553:Isotope Labeling; D010084:Oxidation-Reduction; D010165:Palladium / Q000737:chemistry*; D011854:Radiochemistry / Q000379:methods*; D014508:Urea / Q000737:chemistry*
chemical_list: D001562:Benzimidazoles; D002250:Carbon Radioisotopes; C568644:GSK 1034702; D010165:Palladium; D002248:Carbon Monoxide; D014508:Urea
keywords: PET; carbon monoxide; carbon-11; carbonylation; palladium; ureas