Phosgene → 4-Chloro-3-methylphenyl isocyanate

Participants

Reaction Steps

To the stirred mixture of 4-chloro-3-methylaniline (F1, 1.01 g, 7.13 mmol) and triethylamine (866 mg, 8.56 mmol) in methylene chloride (20 mL) at −20° C. under nitrogen was added phosgene solution (0.15 weight/weight in toluene, 6.15 g, 9.13 mmol) dropwise over 5 min. After addition, the reaction mixture was warmed up to room temperature over 2 h, and then stirred at room temperature for another 2 h. After this time, the reaction mixture was cooled to 0° C., and slowly quenched with saturated aqueous sodium bicarbonate (30 mL). The mixture was extracted with ethyl acetate (100 mL). The organic extract was washed with 2 M hydrochloric acid (50 mL), brine (30 mL), dried over anhydrous sodium sulfate, and filtered. The filtrate was concentrated under reduced pressure. The resulting residue was triturated with methylene chloride (40 mL) and filtered. The filtrate was concentrated under reduced pressure to provide compound F2 as a light brown liquid (1.08 g, 90%): 1H NMR (300 MHz, CDCl3) δ 7.27 (d, J=8.4 Hz, 1H), 6.97 (d, J=2.4 Hz, 1H), 6.88-6.84 (m, 1H), 2.34 (s, 3H).

Provenance & Evidence