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

Participants

Reaction Steps

A flame-dried round bottom flask was charged with 80 (4.37 g, 9.48 mmol) and glacial acetic acid (61 mL). The flask was sealed with a septum and flushed with nitrogen. Zinc-copper couple (6.07 g, Aldrich) was added and the reaction stirred at room temperature for a period of 21 h. The reaction was then heated to 80° C. for 1 h. The reaction mixture was cooled to room temperature, filtered thru a pad of Celite®, washed with EtOAc (200 mL) and concentrated under vacuum. The resulting white solid (residue) was diluted with CH2Cl2 (250 mL) and washed with 0.5 M NaOH (500 mL). The aqueous layer was extracted with CH2Cl2 (2×150 mL) and the combined organic layers were dried (MgSO4), filtered and concentrated. Purification by flash chromatography (SiO2, 5% Acetone-CH2Cl2) afforded 78 (3.64 g, 90%) as a white powder identical in all respects to material isolated in Example 38, step 2.

Provenance & Evidence