反应详情

2.72 g (7.83 mmol) of the alcohol (26) was dissolved in 20 mL of methylene chloride with 1.3 mL (9.4 mmol) of triethylamine and 1.1 g (9.5 mmol) of glycolic anhydride. The mixture was stirred for 2 h (became homogeneous). TLC showed clean reaction (Rf=0.35 in 9:1/methylene chloride:methanol). The solvents were removed by evaporation and the residue was chromatographed on a 1.5×18 inch silica gel column packed with 93% methylene chloride, 5% methanol, and 2% triethylamine. The fractions containing product were combined and solvent was removed by evaporation. Co-evaporation with dry DMF ensured removal of traces of water and of residual volatile solvents. Yield of the colorless syrup (27) was assumed to be 100%. The syrup was dissolved in dry DMF to give a final volume of 23.4 mL (˜0.33 M solution).

1. customThe solvents were removed by evaporation
2. customthe residue was chromatographed on a 1.5×18 inch silica gel column
3. additionThe fractions containing product
4. customsolvent was removed by evaporation
5. customCo-evaporation with dry DMF
6. customremoval of traces of water
7. dissolutionThe syrup was dissolved in dry DMF