The general procedure for the synthesis of bis(2,4,6-trichlorophenyl) malonate from malonic acid and 2,4,6-trichlorophenol was as follows: 2,4,6-trichlorophenol (15.8 g, 80 mmol) and malonic acid (4.1 g, 40 mmol) were added to phosphorus triclosamide (100 mL, 1.05 mol) according to the literature method. The reaction mixture was stirred under reflux conditions for 4 hours until the cessation of the escape of hydrogen chloride gas was confirmed by litmus test. The warm crystalline suspension was slowly poured into ice water (500 g) and stirred continuously for 30 minutes. Off-white crystals were collected by filtration and subsequently transferred to a mixture containing water (100 mL) and saturated aqueous sodium bicarbonate (50 mL). After stirring for 30 min, the crystals were filtered again, washed thoroughly with distilled water (3 x 40 mL) and finally dried under vacuum to afford the target product bis(2,4,6-trichlorophenyl) malonate (18.5 g, 95% yield) as a white fine solid. The structure of the product was confirmed by 1H NMR (400 MHz, CDCl3): δ 7.39 (4H, s, Ar-H), 4.05 (2H, s, CH2).
