820212-22-4Relevant articles and documents
Efficient synthesis of exo-N-carbamoyl nucleosides: Application to the synthesis of phosphoramidate prodrugs
Cho, Jong Hyun,Coats, Steven J.,Schinazi, Raymond F.
supporting information; experimental part, p. 2488 - 2491 (2012/08/27)
An efficient protection protocol for the 6-exo-amino group of purine nucleosides with various chloroformates was developed utilizing N-methylimidazole (NMI). The reaction of an exo-N6-group of adenosine analogue 1 with alkyl/and aryl chloroformates under optimized conditions provided the N6-carbamoyl adenosines (2a-j) in good to excellent yields. The reaction of N6-Cbz-protected nucleosides (5a-c) with phenyl phosphoryl chloride (7) using t-BuMgCl followed by catalytic hydrogenation afforded the corresponding phosphoramidate pronucleotides (8a-c) in excellent yield.
Facile deprotection of O-Cbz-protected nucleosides by hydrogenolysis: An alternative to O-benzyl ether-protected nucleosides
Johnson II, David C.,Widlanski, Theodore S.
, p. 4643 - 4646 (2007/10/03)
(Chemical Equation Presented) Because of side-reactions encountered during hydrogenolysis, benzyl ethers are usually not an effective protecting group for nucleosides. Benzyloxycarbamates provide an alternative to traditional benzyl ethers for protection of nucleoside hydroxyl groups, as they are much more labile to hydrogenolysis. Deprotection conditions using transfer hydrogenolysis are described that avoid the reduction of the pyrimidine nucleobase during deblocking of O-Cbz-protected nucleosides. Additionally, an experiment is described that suggests the nucleobase component of a nucleoside is responsible for the sluggish hydrogenolysis of nucleosides.