4,4',4''-Tris(levulinoyloxy)trityl as a New Type of Primary Hydroxyl Protecting Group

Article abstract of DOI:10.1246/bcsj.58.336

The 4,4',4''-tris(levulinoxy)trityl (TLTr) group was introduced selectively on the 5'-oxygen of thymidine by use of in situ generated 4,4',4''-tris(levulinoyloxy)trityl bromide.The TLTr group was found to be sufficiently stable to acids and readily removed by hydrazinolysis followed by warming to 50 deg C in pyridine-acetic acid without damage of other protecting groups such as the O-acetyl and 4,4'-dimethoxytrityl groups.The utility of this new protecting group was demonstrated by the successful synthesis of thymidylyl(3'-5')thymidine where the TLTr group was employed as 5'-hydroxyl-protecting group.