反应详情

A mixture of 20 g (68 mmol) of 4-(tert-butyl-dimethyl-silanyloxy)-2-methyl-benzoic acid ethyl ester, 12.1 g (68 mmol) of N-bromosuccinimide, 1.5 g (6.8 mmol) of benzoyl peroxide in 230 mL of carbon tetrachloride was heated at reflux temperature for 5 hours. The resultant mixture was cooled, filtered through a plug of silica gel, and concentrated under reduced pressure. To the residue (12.2 g) was added 8.0 g (28.7 mmol) of N-(2,4-dimethoxy-benzyl)glycine ethyl ester, 3.96 g (28.7 mmol) of potassium carbonate, and 65 mL of anhydrous DMF and the mixture was stirred for 6.5 hours. The mixture was then partitioned into a biphasic water-ethyl acetate mixture and the isolated organic layer was washed with brine, dried over anhydrous magnesium sulfate, and concentrated. The residue was purified by flash chromatography: eluting the desired product from silica gel with a gradient of 10-90% ethyl acteate in hexanes. 5.33 g of the title compound (yellow oil) was isolated; MS (ESI+): 432.2 (M+1)

1. temperaturewas heated
2. temperatureat reflux temperature for 5 hours
3. filtrationfiltered through a plug of silica gel
4. concentrationconcentrated under reduced pressure
5. customThe mixture was then partitioned into a biphasic water-ethyl acetate mixture
6. washthe isolated organic layer was washed with brine
7. dry with materialdried over anhydrous magnesium sulfate
8. concentrationconcentrated
9. customThe residue was purified by flash chromatography
10. washeluting the desired product from silica gel with a gradient of 10-90% ethyl acteate in hexanes