Iodine → Triphenylphosphine Oxide

Participants

Reaction Conditions

Reaction Steps

A mixture of 2′,3′,5′-tri-O-acetyl-2-N-tritylguanosine (5.92 g, 9.1 mmol), I2 (11.55 g, 45.5 mmol), Ph3P (11.93 g, 45.5 mmol) and 2-propylimidazole (5.01 g, 45.5 mmol) was stirred in toluene (180 mL) at 95° C. for 15 min. DIPEA (15.9 mL, 11.80 g, 91.3 mmol) was added, and the mixture was stirred at 95° C. overnight. After removal of volatiles in vacuo, the residue was extracted with boiling EtOAc. The combined EtOAc extracts were evaporated to dryness, and the residue was dried under vacuum. The material obtained was stirred in TFA/H2O (9:1, 250 mL) at 0° C. for 4 h. Volatiles were evaporated in vacuo, and the residue was chromatographed (CH2Cl2→MeOH/CH2Cl2, 1:12). This solid material was treated with charcoal in MeOH. Volatiles were evaporated in vacuo, and the residue was dissolved in CH2Cl2 and washed (NaHCO3/H2O, brine) and dried (Na2SO4) to give 9-(2,3,5-tri-O-acetyl-β-D-ribofuranosyl)-2-amino-6-(2-propylimidazol-1-yl)purine as a colored solid (3.20 g, 81%, contaminated with Ph3PO).

Provenance & Evidence