Rapid synthesis of F-18 and H-2 dual-labeled altanserin, a metabolically resistant PET ligand for 5-HT2a receptors
作者:Ping-Zhong Tan、Ronald M. Baldwin、Tao Fu、Dennis S. Charney、Robert B. Innis
DOI:10.1002/(sici)1099-1344(199905)42:5<457::aid-jlcr206>3.0.co;2-0
日期:1999.5
F-18 and H-2 dual-labeled altanserin (3, [F-18]d-ALT), a novel PET tracer for 5-HT2A receptors with metabolically resistant properties, was synthesized by [F-18]fluoride displacement of the corresponding deuterated nitro precursor in 32% yield (EOB) in 108 min with radiochemical purity 95% and specific activity >1000 mCi/mu mol (EOS). The key intermediate ethyl N-(2-chloroethyl-2,2-d(2))carbamate (7 was obtained by LiAlD4 reduction of a glycine ester (93%), chlorination and carbamoylation (79%). 4-(4-Nitrobenzoyl)piperidine (13) was synthesized (60%) by improving the published coupling reaction of p-nitrophenyltrimethylstannane (10), obtained from p-iodonitrobenzene and (CH3)(6)Sn-2 (94%), with 1-benzoylisonipecotic acid chloride (11) followed by acid hydrolysis. 13 was alkylated with 7 (82%), hydrolyzed and condensed with methyl o-isothiocyanatobenzoyate to provide with the precursor deuteronitmaltanserin (4, 75%).