Diisopropylethylamine → Methyl 4-[(5-bromo-2-methyl-benzoyl)amino]-3,5-dimethyl-benzoate

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Reaction Steps

To a solution of 5-bromo-2-methylbenzoic acid (2.0 g, 0.008 mol) in CH2Cl2 (20 mL) at 0° C. are added methyl 4-amino-3,5-dimethylbenzoate (1.28 g, 0.0072, see preparation 12) and N,N-diisopropylethylamine (4.12 g, 0.032 mol). After stirring the reaction mixture for 10 minutes, 1-propanephosphonic acid cyclic anhydride (50% solution in ethyl acetate, 7.63 g, 0.024 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 12% ethyl acetate in hexane to give the title compound as a white solid (2.9 g, 97%). Mass spectrum (m/z): 376.0 (M+1).

Provenance & Evidence