43 g (0.076 moles) of 7-(2,3,4,6-tetra-O-acetyl-β-D-galactopyranosyloxy)coumarin-4-acetate (i.e. compound 1 prepared as described in Scheme 1) was dissolved in 430 ml of methylene chloride in a 1 liter RB flask. 43 ml (0.712 moles) of ethanolamine was dissolved in 43 ml of methanol and added to the above solution. The solution was stirred at room temperature for 60 hrs and the resulting solid residue was filtered and washed with 50 ml of methylene chloride. The solid was suspended in 250 ml of methanol and stored in the freezer for 12 hrs. The solid was filtered again and suspended in 700 ml of methanol and refluxed for 30 min. The cloudy suspension was cooled to room temperature, then further cooled in an ice bath and filtered. The wet solid thus obtained was suspended in 200 ml of ether and stirred for 30 min., then filtered and vacuum dried at room temperature to give 12 g of an off-white solid. The yield was 37%. The structure was confirmed by 1H NMR and MS (as in Example 1).
