反应详情

Acetic anhydride (89.3 mL, 0.95 mol) was added rapidly to a magnetically stirred suspension of anhydrous guanosine (76.56 g, 0.27 mol), 4-dimethylaminopyridine (DMAP, 2.47 g, 0.02 mol), and triethylamine (TEA, 149 mL, 1.07 mol) in acetonitrile (500 mL, synthesis grade). The mixture was stirred magnetically, and, after a short induction period, a substantial exotherm was observed as the temperature of the mixture rose to about 50° C. Within 3-5 minutes, the mixture became a faintly cloudy solution. This solution was stirred for 30 minutes, at which time TLC (silica gel plates eluted with 6:3:1 ethyl acetate:DMF:1-butanol) showed only the title compound and a trace of N2 -acetyl-2',3',5'-tri-O-acetylguanosine at higher Rf and DMAP at very low Rf.

1. customrose to about 50° C