Reaction detail

A solution of 1.8 g (5.9 mmol) of 3-amino-4-methylaminobenzoic acid-N-(n-propyl)-N-(2-ethoxycarbonylethyl)amide [prepared analogously to 3-amino-4-ethylaminobenzoic acid-N-phenyl-N-(2-ethoxycarbonylethyl)amide], 1.1 g (6.8 mmol) of N,N′-carbonyldiimidazole, and 0.65 g (6.9 mmol) of chloroacetic acid in 75 mL tetrahydrofuran was stirred for 1 hour at room temperature. Then the solvent was distilled off in vacuo, and the crude product was purified by flash chromatography (silica gel; methylene chloride/ethanol=49:1). Yield: 1.7 g (77% of theory) yellow oil; Rf value: 0.58 (silica gel; ethyl acetate/ethanol/ammonia=90:10:1).

1. distillationThen the solvent was distilled off in vacuo
2. customthe crude product was purified by flash chromatography (silica gel; methylene chloride/ethanol=49:1)