反应详情

To a solution of 5-bromo-2-methylbenzoic acid (2.0 g, 0.0093 mol) in CH2Cl2 (20 mL) at 0° C. are added methyl 3-amino-2,4-dimethylbenzoate (1.49 g, 0.0084 mol, see preparation 10) and N,N-diisopropylethylamine (4.79 g, 0.0372 mol). After stirring the reaction mixture for 10 minutes, 1-propanephosphonic acid cyclic anhydride (50% solution in ethyl acetate, 8.87 g, 0.028 mol) is added via syringe and stirred at 50° C. After 16 hours, the solvent is removed under reduced pressure and the residue is diluted with water and extracted twice with ethyl acetate. The organic layers are combined and dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The resulting residue is purified by flash chromatography (silica gel) using 10% ethyl acetate in hexane to give the title compound as a white solid (2.80 g, 80%). Mass spectrum (m/z): 376.1 (M+1).

1. stirringstirred at 50° C
2. waitAfter 16 hours
3. customthe solvent is removed under reduced pressure
4. additionthe residue is diluted with water
5. extractionextracted twice with ethyl acetate
6. dry with materialdried over anhydrous Na2SO4
7. filtrationfiltered
8. concentrationconcentrated under reduced pressure
9. customThe resulting residue is purified by flash chromatography (silica gel)