Diphenyl (2,3-Dihydro-2-thioxo-3-benzoxazolyl)phosphonate

Experimental procedure²⁾: Diphenyl (2,3-dihydro-2-thioxo-3-benzoxazolyl)phosphonate (3.38 g, 8.8 mmol) is added to a solution of 1 (2.56 g, 8 mmol) and triethylamine (1.12 mL, 8 mmol) in 10 mL of NMP. After stirring for 30 min at room temperature, 3-iodoaniline (1.75 g, 8 mmol) is added. The solution is stirred for 2 h and poured into 1% aqueous sodium hydrogen carbonate. Then EtOH is added to the mixture. The precipitate is filtered off washed with EtOH/water (200 mL/300 mL). The product is dissolved in boiling EtOH (600 mL) and cooled to recrystallize. The product is further purified by recrystallization to afford 2 as a white powder (3.14 g, 6.02 mmol, 75%).