The 3′-O-TBDMS-Uridine Tetraphosphate [8] (2.55 mg, 0.00376 mmol) was taken up in CH3CN (Aldrich anhydrous, 160 μL). Tetrabutylammonium fluoride in THF (1.0 M, Aldrich, 113 μL, 0.113 mmol) and HOAc (glacial, Aldrich, 2.2 μL, 0.0376 mmol) were added to the solution. The resulting reaction mixture was allowed to stir for 21 hours at ambient temperature. HPLC analysis of the reaction at this time showed no remaining silyl ether. The volatile materials were removed on a rotary evaporator. The product mixture was resuspended in H2O, and the product was purified by reversed phase HPLC. (Column: Zorbax SB-C18, 9.4 mm×25 cm. Solvent A: 0.1 M TEAA, 2.5% CH3CN, pH=7.0; Solvent B: CH3CN. Flow rate: 4.0 mL/minute. Gradient: t=0 minutes, 100% A; t=15 minutes, 75% A/25% B; t=15.01 minutes, 100% B; t=20 minutes, 100% A; t=27 minutes, 100% A. Retention time: 7.05 minutes). The purified material was lyophilized. The resulting material was resuspended and lyophilized a total of 5 times to ensure complete removal of TEAA salts. Before the final lyophilization, the material was quantified by UV (2.00 mg, 94% yield). The compound [9] obtained in this manner was a white solid.
