反应详情

A solution of 2,3:5,6-di-O-isopropylidene-D-mannofuranose (diacetone mannose) (20 g, 76.9 mmol) in dichloromethane (100 ml) was added to a solution of pyridinium chlorochromate (33.2 g, 2.0 equiv) and dry powdered molecular sieve (40 g) in dichloromethane (300 ml) at 0° C. under nitrogen. The reaction mixture was stirred at room temperature for 30 min [when TLC (ether:hexane, 2:1) showed no starting material (Rf 0.36) and one major product (Rf 0.24)], diluted with ether (400 ml) and filtered through a silica plug. The silica plug was washed with ether and the filtrates were combined and the solvents removed to give, after recrystallization from ether, 2,3:5,6-di-O-isopropylidene-D-mannono-1,4-lactone (11), (18.0 g, 90%), m.p. 125°-126° C. [lit. m.p. 125°-125° C.; Ohle et al., Chem. Ber. 58, 2590 (1925); Goodyear and Haworth, J. Chem. Soc. 1927, 3136⟧

1. dry with materialdry powdered molecular sieve (40 g) in dichloromethane (300 ml) at 0° C. under nitrogen
2. additiondiluted with ether (400 ml)
3. filtrationfiltered through a silica plug
4. washThe silica plug was washed with ether
5. customthe solvents removed
6. customto give
7. customafter recrystallization from ether, 2,3:5,6-di-O-isopropylidene-D-mannono-1,4-lactone (11), (18.0 g, 90%), m.p. 125°-126° C. [lit. m.p. 125°-125° C.