反应详情

Into a solution of 9.57 g (44.18 mmol) of 2-chloro-3,5-dimethoxy-benzoic acid and 4.78 g (47.3 mmol) of triethylamine in 250 mL of toluene was added 13.57 g (49.3 mmol) diphenylphosphoryl azide. The reaction was refluxed for 4 hours. To the reaction was added 3.63 g (49.0 mmol) of tert-butanol. The reaction was refluxed overnight then concentrated in vacuo. The residue was partitioned between a cold 1N solution of citric acid and ethyl acetate. The ethyl acetate layer was washed twice with each of the following: cold IN citric acid solution, water, and then saturated sodium bicarbonate solution. The ethyl acetate layer was dried with magnesium sulfate and concentrated in vacuo. The residue was dissolved in tetrahydrofuran, added silica gel and concentrated to dryness. The residue was chromatographed on silica gel, eluting with hexane/diethyl ether (9:1 v/v), to give 8.14 g (64%) of the title compound: mp 94.5-95.5° C.

1. temperatureThe reaction was refluxed for 4 hours
2. temperatureThe reaction was refluxed overnight
3. concentrationthen concentrated in vacuo
4. customThe residue was partitioned between a cold 1N solution of citric acid and ethyl acetate
5. washThe ethyl acetate layer was washed twice with each of the following: cold IN citric acid solution, water
6. dry with materialThe ethyl acetate layer was dried with magnesium sulfate
7. concentrationconcentrated in vacuo
8. dissolutionThe residue was dissolved in tetrahydrofuran
9. additionadded silica gel
10. concentrationconcentrated to dryness
11. customThe residue was chromatographed on silica gel
12. washeluting with hexane/diethyl ether (9:1 v/v)