反应详情

HCl (gas) was bubbled for 1.5 hours into a solution of 50 g (99.16 mole) of the compound (12) dissolved in 460 ml of anhydrous dichloromethane and 7.5 ml of acetyl chloride at 0° C. The resulting solution was kept in a refrigerator for 12 hours and then evaporated in vacuo. The residue was coevaporated with toluene (3×150 ml) at 45° C. and redissolved in 105 ml of acetonitrile. To this solution, 13 ml of water was added dropwise at 0° C. A white solid began to precipitate from the mixture after 30 minutes, after which the mixture was kept in a refrigerator for 2 hours to induce additional precipitation. After filtration of the resulting solid, the filter cake was. carefully washed with cold diethylether to remove the reaction by-product 1-hydroxy-isomer, which is indistinguishable by TLC from the compound (13). The white solid thereby obtained was dissolved in ethyl acetate. The solution was washed with saturated sodium bicarbonate to remove the remaining HCl, dried over MgSO4 and filtered. The solvent was removed from the filtrate to obtain 29.2 g (Yield: 63.7%) of the compound (13) in the form of a white solid.

1. customat 0° C
2. customevaporated in vacuo
3. customwas coevaporated with toluene (3×150 ml) at 45° C.
4. dissolutionredissolved in 105 ml of acetonitrile
5. additionTo this solution, 13 ml of water was added dropwise at 0° C
6. customto precipitate from the mixture after 30 minutes
7. waitafter which the mixture was kept in a refrigerator for 2 hours
8. customprecipitation
9. filtrationAfter filtration of the resulting solid
10. washcarefully washed with cold diethylether
11. customto remove the reaction by-product 1-hydroxy-isomer, which
12. customThe white solid thereby obtained
13. washThe solution was washed with saturated sodium bicarbonate
14. customto remove the remaining HCl
15. dry with materialdried over MgSO4
16. filtrationfiltered
17. customThe solvent was removed from the filtrate