162138-71-8Relevant articles and documents
Improved synthesis of an ergothioneine PET radioligand for imaging oxidative stress in Alzheimer’s disease
Beelman, Robert B.,Behof, William J.,Harrison, Fiona E.,Haynes, Justin R.,Matsubara, Joanne A.,Peterson, Todd E.,Pham, Wellington,Rosenberg, Adam J.,Tantawy, Mohammed N.,Whitmore, Clayton A.,Wijesinghe, Printha
, (2022/02/16)
L-ergothioneine (ERGO) is a potent antioxidant with cytoprotective effects. To study ERGO biodistribution and detect oxidative stress in vivo, we report an efficient and reproducible preparation of [11C]-labeled ERGO PET radioligand based on protecting the histidine carboxylic group with a methyl ester. Overall, this new protection approach using methyl ester improved the chemical yield of a 4-step reaction from 14% to 24% compared to the previous report using t-butyl ester. The [11C]CH3 methylation of the precursor provided the desired product with 55 ± 10% radiochemical purity and a molar activity of 450 ± 200 TBq·mmol?1. The [11C]ERGO radioligand was able to detect threshold levels of oxidative stress in a preclinical animal model of Alzheimer’s disease.
Synthesis of L-(+)-ergothioneine
Xu,Yadan
, p. 6296 - 6301 (2007/10/03)
The first synthesis of L-(+)-ergothioneine (1), a rare natural amino acid, is described. The key step is the direct transformation of the imidazole derivative 11 into imidazole-2-thione 12. This reaction consists of the cleavage and the re-formation of imidazole ring (ANRORC) with phenyl chlorothionoformate via a Bamberger-type intermediate. The conditions used are mild enough to preserve the asymmetric center at the 1a-carbon. The release of enantiomerically pure L-ergothioneine (1) from the ammonium derivative 15 was performed under acidic conditions to avoid the very easy racemization of the betaine function. An efficient and high-yield sypthesis of 2-mercapto-L-histidine (2) which uses the new imidazole-2-thione formation reaction is also described.
