Conformationally locked nucleosides. Synthesis and stereochemical assignments of 3'-N,5'-C-bridged 3'-amino-3'-deoxythymidines

Article abstract of DOI:10.1016/S0040-4039(99)01205-8

3'-Amino-3'-deoxythymidine was converted, in multi-steps, to its 5'-O- (4,4'-dimethoxytrityl)-5'-C-tosyloxyethyl-3'-N-carbobenzoxy derivative 7 and 5'-C-mesyloxyethyl-3'-N-(9-fluorenyl)methoxycarbonyl derivatives 6 and 11. Subsequent hydrogenolysis or treatment with DMAP afforded 3'-N,5'-C-bridged bicyclic thymidines. Stereochemical assignments were accomplished with the help of NOE.