Triethylamine → 5-Acetylamino-7-chloro-3-(2,3,5'-tri-O-acetyl-beta-D-ribofuranosyl)-thiazolo[4,5-d]pyrimidin-2-one

Participants

Reaction Conditions

Reaction Steps

Phosphorus oxychloride (6.42 mL, 70.2 mmol) was added dropwise to a solution of 16 (3.40 g, 7.02 mmol), triethylamine (1.96 mL, 14.04 mmol), and chloroform (14 mL) over 30 minutes at room temperature under nitrogen. The reaction mixture was then heated to 70° C. for 30 h. The mixture was cooled to ambient temperature, added dropwise over 2 h to a 0° C. solution of saturated aq. NaHCO3 (500 mL), and stirred for an additional 1 h. The layers were separated, aqueous layer back extracted with methylene chloride (2×100 mL), combined organic layers were dried (MgSO4), filtered and concentrated to a yellow solid. Purification was achieved via flash chromatography (SiO2, 5% Acetone-CHCl3) to afford 81 (3.17 g, 90%) as a white solid: 1H NMR (400 MHz, d6-DMSO) δ 11.08 (s, 1H), 6.09 (d, J=4.0 Hz, 1H), 5.99 (dd, J=6.0, 4.0 Hz, 1H), 5.76 (t, J=6.8 Hz, 1H), 4.41 (dd, J=11.2, 3.2 Hz, 1H), 4.32 (td, J=7.2, 3.2 Hz, 1H), 4.24 (dd, J=11.6, 6.8 Hz, 1H), 2.18 (s, 3H), 2.12 (s, 3H), 2.11 (s, 3H), 2.03 (s, 3H); [M+H]+ 503.3.

Provenance & Evidence