Résumé
The rationale for a pronucleotide approach based on the use of phosphotriesters which incorporate enzyme-mediated bio-labile protection is discussed in detail. Among the studied bio-labile phosphate protecting groups, the S-acyl-2-thioethyl (SATE) groups appeared the most promising as exemplified in cell culture systems in the case of the pronucleotides of 3'-azido-3'-deoxythymidine, 2',3'-didehydro-3'-deoxythymidine, 2',3'-dideoxyadenosine and acyclovir In vivo implementations of such bis(SATE) pronucleotides have been planned for future animal studies.