Tetra-n-butylammonium peroxydisulfate has been found to be a good deprotecting reagent for removal of the trityl group: Treatment of 5'-O-dimethoxytrityl uridine or thymidine with tetra-n-butylammonium peroxydisulfate gave the corresponding dedimethoxytritylated nucleosides in excellent yields under neutral and mild conditions and without causing any side reactions such as cleavage of the glycosidic bond. (C) 1997 John Wiley & Sons, Inc.