title: Studies toward labeling cytisine with [11C]phosgene: rapid synthesis of a delta-lactam involving a new chemoselective lithiation-annulation method.
abstract: With the aim of the radiolabeling of cytisine, a potent agonist of nicotinic receptors, with [(11)C]phosgene, the rapid synthesis of a lactam model of our target has been studied. The key step of the delta-lactam formation is a new chemoselective lithiation-annulation method, under high dilution, of a suitable piperidinylcarbamoyl chloride. This precursor was obtained from (2-hydroxyethyl)piperidine in a linear synthetic sequence involving a Corey-Fuchs olefination of the corresponding aldehyde, followed by a selective reduction, using a diimide equivalent, of an iodoalkyne into a (Z)-iodopropene piperidine. This alkene served as main precursor to study the cyclization according to several procedures using phosgene as the required carbonylating reagent.
authors.affiliation: Laboratoire de Chimie Moléculaire et Thio-organique, CNRS UMR 6507, ENSICAEN, Université de Caen-Basse Normandie, 6 Boulevard du Maréchal Juin, F14050 Cannes Cedex, France. rouden@ismra.fr
authors.forename: Jacques
authors.initials: J
authors.lastname: Rouden
authors.forename: Thomas
authors.initials: T
authors.lastname: Seitz
authors.forename: Laurent
authors.initials: L
authors.lastname: Lemoucheux
authors.forename: Marie-Claire
authors.initials: MC
authors.lastname: Lasne
mesh_terms: D000470:Alkaloids / Q000737:chemistry*; D001392:Azocines / Q000737:chemistry*; D002250:Carbon Radioisotopes; D007553:Isotope Labeling; D007769:Lactams / Q000138:chemical synthesis*; D015394:Molecular Structure; D010705:Phosgene / Q000737:chemistry*; D011807:Quinolizines / Q000737:chemistry*; D000093843:Quinolizidine Alkaloids
chemical_list: D000470:Alkaloids; D001392:Azocines; D002250:Carbon Radioisotopes; D007769:Lactams; D010705:Phosgene; D011807:Quinolizines; C004712:cytisine; D000093843:Quinolizidine Alkaloids