反应详情

A mixture of 50 g. of D-mannose, 1,500 ml. of anhydrous acetone and 35 ml. of concentrated sulfuric acid was agitated. D-mannose was completely dissolved after 2 to 3 hours to give a light yellow solution. The reaction mixture was then neutralized with anhydrous sodium carbonate. After filtering the reaction mixture, small amounts of active carbon and anhydrous sodium carbonate were added to the filtrate, and it was refluxed for 1 hour and was again filtered. The filtrate was concentrated to give a solid. The solid was taken out and was recrystallized from petroleum ether to give 32.0 g. of 2,3:5,6-di-O-isopropylidene-D-mannofuranose (yield: 44.3%). The melting point of the product was 122° to 123° C.

1. additionA mixture of 50 g
2. customto give a light yellow solution
3. filtrationAfter filtering the reaction mixture, small amounts of active carbon and anhydrous sodium carbonate
4. additionwere added to the filtrate, and it
5. temperaturewas refluxed for 1 hour
6. filtrationwas again filtered
7. concentrationThe filtrate was concentrated
8. customto give a solid
9. customwas recrystallized from petroleum ether
10. customto give 32.0 g