Hydrochloric Acid → 4-[2-(2,5-Dioxoimidazolidin-1-yl)ethoxy]-3-methoxy-2-nitrobenzaldehyde

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Reaction Steps

A solution of 2-(4-dimethoxymethyl-2-methoxy-3-nitrophenoxy)ethylamine (0.16 g, 0.56 mmol) obtained in Step 3 of Example 338 in THF (5.0 mL) was added with triethylamine (0.23 mL, 1.7 mmol) and ethyl isocyanoacetate (0.09 mL, 0.84 mmol), followed by stirring at room temperature for 1 hour. The reaction mixture was added with water and extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate and the solvent was evaporated under reduced pressure to obtain crude product. The product was added with a mixed solvent of acetone (2.0 mL) and 6 mol/L hydrochloric acid (1.0 ml) and heated under reflux for 2.5 hours. The reaction mixture was neutralized by 2 mol/L aqueous sodium hydroxide solution and then extracted with ethyl acetate. The organic layer was washed with saturated brine, dried over anhydrous magnesium sulfate and the solvent was evaporated under reduced pressure to obtain 4-[2-(2,5-dioxoimidazolidin-1-yl)ethoxy]-3-methoxy-2-nitrobenzaldehyde (0.08 g, 42%).

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