Hydrochloric Acid → 4-Isothiocyanato-2-chlorobenzoic acid

Participants

Reaction Steps

A methylene chloride solution (235 mL) of triethylamine (30.6 mL, 219.5 mmol) and thiocarbonyldiimidazole (23.01 g, 129.14 mmol) was dropped to a methylene chloride solution (130 mL) of 4-amino-2-chlorobenzoic acid (18.84 g, 109.82 mmol) under cooling with ice, followed by stirring for one hour while an internal temperature of at most 10° C. was maintained. 4M hydrochloric acid (120 mL, 480 mmol) was dropped so that the internal temperature became at most 10° C., followed by stirring under cooling with ice for one hour. Water (10 mL) was added, and the formed pink solid was collected by filtration, washed with water (100 mL) five times and dried under reduced pressure to obtain 4-isothiocyanato-2-chlorobenzoic acid as a colorless solid (21.36 g, yield: 91%, HPLC purity: 98.2%).

Provenance & Evidence