Abstract
The levulinyl group has been employed for protection of the 5'-hydroxyl group in the synthesis of oligoribonucleotides by the phosphoramidite approach, using the acid-labile 2'-tetrahydro-furanyl group. The hydrazine treatment was performed for 10 minutes in order to remove the levulinyl group on controlled pore glass. Four decaribonucleotides (AAAAAAAAAU, GGGGGGGGGU, CCCCCCCCCU and UUUUUUUUUU) and a heneicosamer (GCCUAGCUGAUGAAG-GGUGAU) were prepared with an automatic synthesizer in good yields.