1: With phthalic anhydride; urea hydrogen peroxide addition compound in dichloromethane T=23°C; 2: With p-toluenesulfonyl chloride in dichloromethane 3: With ammonium chloride; triethylamine T=23°C;

1.1: urea hydrogen peroxide addition compound; phthalic anhydride / dichloromethane / 12 h / 20 - 25 °C / |Inert atmosphere 2.1: p-toluenesulfonyl chloride / dichloromethane / |Inert atmosphere 2.2: |Inert atmosphere View Scheme