Phenyl isocyanate → 4-Chloro-2-[[(phenylamino)carbonyl]amino]benzoic acid

Participants

Reaction Steps

2-Amino-4-chloro-benzoic acid (515 mg, 3.0 mmol) was suspended in dry THF (5 ml) and phenylisocyanate (429 mg, 3.6 mmol) was added. Triethylamine (303 mg, 3.0 mmol) was added and the mixture was stirred for 2 hours. The mixture was diluted with 75 ml ethyl acetate and extracted into 150 ml 1 M aqueous NaOH, and washed once with 50 ml ethyl acetate. The aqueous phase was then acidified with 4 M aqueous HCl and the product extracted with 2×100 ml ethyl acetate. The organic solvent was dried (Na2SO4) and reduced under vacuum, and the product recrystallised from acetone/water to yield 680 mg (78%) of off-white crystals (m.p. 186-188° C.).

Provenance & Evidence