Xu, Youwen; Cankaya, Aylin Sibel; Hoque, Ruma; Lee, So Jeong; Shea, Colleen; Kersting, Lena; Schueller, Michael; Fowler, Joanna S.; Szalda, David; Alexoff, David; Riehl, Barbara; Gleede, Tassilo; Ferrieri, Richard A.; Qu, Wenchao published an article in 2018, the title of the article was Synthesis of L-[4-11C]asparagine by ring-opening nucleophilic 11C-cyanation reaction of a chiral cyclic sulfamidate precursor.Safety of tert-Butyl trichloroacetimidate And the article contains the following content:
The development of a convenient and rapid method to synthesize radiolabeled, enantiomerically pure amino acids (AAs) as potential positron emission tomog. (PET) imaging agents for mapping various biochem. transformations in living organisms remains a challenge. This is especially true for the synthesis of carbon-11-labeled AAs given the short half-life of carbon-11 (11C, t1/2=20.4 min). A facile synthetic pathway to prepare enantiomerically pure 11C-labeled L-asparagine was developed using a partially protected serine as a starting material with a four-step transformation providing a chiral five-membered cyclic sulfamidate as the radiolabeling precursor. Its structure and absolute configuration were confirmed by X-ray crystallog. Utilizing a [11C]cyanide nucleophilic ring opening reaction followed by selective acidic hydrolysis and deprotection, enantiomerically pure L-[4-11C]asparagine was synthesized. Further optimization of reaction parameters, including base, metal ion source, solvent, acid component, reaction temperature and reaction time, a reliable two-step method for synthesizing L-[4-11C]asparagine was presented: within a 45±3 min (n = 5, from end-of-bombardment), the desired enantiomerically pure product was synthesized with the initial nucleophilic cyanation yield of 69±4 % (n = 5) and overall two-step radiochem. yield of 53±2 % (n = 5) based on starting [11C]HCN, and with radiochem. purity of 96±2 % (n = 5). The experimental process involved the reaction of tert-Butyl trichloroacetimidate(cas: 98946-18-0).Safety of tert-Butyl trichloroacetimidate
The Article related to asparagine 11c labeled enantioselective total radiosynthesis pet imaging agent, chiral cyclic sulfamidate precursor ring opening nucleophilic cyanation hydrolysis, amino acid crystal structure, racemization cyanation kinetics reaction mechanism, amino acids, nucleophilic, radiochemistry, ring opening, sulfamidate and other aspects.Safety of tert-Butyl trichloroacetimidate
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