Sodium hydride → Methyl{[(4-ethoxyphenyl)sulfonyl]-4-methylanilino}acetate

The crude N-aryl-benzenesulfonamide building block XIII, e.g. 4-ethoxy-N-(4-methylphenyl)benzenesulfonamide (3.087 g, 10.6 mmol), was dissolved in DMF (10 mL) and was added to a suspention of NaH (13.6 mmol, 0.593 mg of NaH 55-65% in oil) in DMF (30 mL). The mixture was stirred 45 min at room temperature. 2-Bromoacetic acid methyl ester (1.45 mL, 15.9 mmol) was added dropwise. The resulting mixture was stirred at room temperature overnight. The solvents were evaporated, affording the desired product, e.g. methyl{[(4-ethoxyphenyl)sulfonyl]-4-methylanilino}acetate (3.816 g, quantitative crude yield) as a light yellow solid, in 96.1% purity by HPLC (MaxPlot detection between 230 and 400 nm).