tert-Butanol → Tri-O-acetylguanosine

Participants

Reaction Steps

To a suspension of guanosine (1) (Dried in vacuo over P2O5 for 2 days at 100°, 10.6 g, 37.6 mmole) in DMF (distilled from P2O5,30 ml), Ac2O (re-distilled, 22.4 ml) and pyridine (distilled from KOH, 11.2 ml) were added. The mixture was heated with stirring at 75°. The mixture became clear solution after 1.5 h. Heating was continued for another 2.5 h. The resulting clear solution is filtered while hot, cooled to temperature, and evaporated in vacuo to afford a heavy, crystalline suspension. A portion (35 ml) of 2-methyl-2-propanol was added. The suspension is filtered, and the filter cake was washed with 2-methyl-2-propanol and dried. This crystalline is the hemi-solvate with HCONMe2, and was added to boiling 2-methyl-2-propanol, and the suspension was boiled under reflux for 5 min, cooled and refrigerated for 10 h at −5°. After filtration, the white crystalline was dried in air overnight, dried in vacuo over P2O5 for 2 days at 80°, to give white powder (12.0 g, 78.4%, mp:227-230°, lit. 226-231°).

Provenance & Evidence