Boron trifluoride etherate → HCID 70360285, compound

Participants

Reaction Conditions

Reaction Steps

A cold (0°-5° C.) solution of 12.2 g of a mixture of 3,6-anhydro-2-deoxy-4,5,7-tris-O-(phenylmethyl)-D-gluco-heptitol and 2,5-anhydro-6-deoxy-1,3,4-tris-O-(phenylmethyl)-D-manno-heptitol in 64 ml of acetic anhydride was treated with 370 μl of borontrifluoride etherate under argon. After 13/4 hours, 53 ml of saturated aqueous sodium bicarbonate was added, the mixture was stirred at 0° C. for 15 minutes, then at ambient temperature for 15 minutes and the volatiles removed. The residue was taken up in ether/water. The organic layer was separated, dried and evaporated. The residue was taken up in 74 ml of methanol, a solution of 15.4 g of potassium carbonate in 90 ml of water added and this mixture stirred at reflux for 45 minutes. The volatiles were removed, the residue taken up in ether/water and the organic layer separated and evaporated. The 12 g of residue was purified by high pressure liquid chromatography on silica gel, eluting first with hexane:ethyl acetate (1:1), and then with hexane:ethyl acetate (1:3), giving 3,6-anhydro-2-deoxy-4,5-bis-O-(phenylmethyl)-D-gluco-heptitol in 20% yield and 3,6-anhydro-2-deoxy-4,5-bis-O-(phenylmethyl)-D-manno-heptitol in 65% yield.

Provenance & Evidence