Chakraborty P K, Mangner T J, Chugani D C, Muzik O, Chugani H T
Children's Hospital of Michigan, Department of Pediatric Imaging, Wayne State University School of Medicine, Detroit 48201, USA.
Nucl Med Biol. 1996 Nov;23(8):1005-8. doi: 10.1016/s0969-8051(96)00127-8.
Alpha-[11C]methyl-L-tryptophan (AMT) has been synthesized by stereoselective methylation with [11C]methyl iodide of the lithium-enolate generated by treating dimethyl 2(S), 3a(R), 8a(S)-(+)-hexahydro-8(phenylsulfonyl)pyrrolo [2, 3-b]indole-1,2-dicarboxylate (2) with lithium diisopropyl amide (LDA) at -55 degrees C, followed by ring opening using trifluoroacetic acid and alkaline hydrolysis of the protecting groups. The crude product was purified by a simple reverse-phase C-18 Sep-Pak procedure. The purified product was isolated with an average radiochemical yield of 53 +/- 12% (decay corrected) in 30-35 min from [11C]methyl iodide. At end of synthesis (EOS), 138 +/- 35 mCi (n = 24) of product was collected with a specific activity of ca. 1-1.3 Ci/mumol (EOS) (4-5 Ci/mumol @ EOB) starting from 1.5 Ci (EOB) of [11C]CO2.
α-[¹¹C]甲基-L-色氨酸（AMT）的合成方法如下：在-55℃下，用二异丙基氨基锂（LDA）处理2(S), 3a(R), 8a(S)-(+)-六氢-8-(苯基磺酰基)吡咯并[2, 3-b]吲哚-1,2-二羧酸二甲酯（2）生成烯醇锂，再用碘甲烷进行立体选择性甲基化，随后用三氟乙酸开环并对保护基进行碱性水解。粗产物通过简单的反相C-18 Sep-Pak程序进行纯化。从碘甲烷开始，在30 - 35分钟内以平均放射化学产率53±12%（衰变校正）分离得到纯化产物。在合成结束时（EOS），从1.5 Ci（EOB）的[¹¹C]CO₂开始，收集到138±35 mCi（n = 24）的产物，其比活度约为1 - 1.3 Ci/μmol（EOS）（EOB时为4 - 5 Ci/μmol）。
