Sulfuric Acid → 2-Amino-5-nitro-4-trifluoromethyl-benzoic acid

Participants

Reaction Conditions

Reaction Steps

A solution of 49.5 g (169 mmol) of 2-acetylamino-5-nitro-4-trifluoromethyl-benzoic acid in 600 ml of methanol and 100 ml of water is cooled to 0° C. and 71.1 ml (1.33 mol) of concentrated H2SO4 are added dropwise. Upon completion of the addition, the mixture is heated to reflux for 1 hour. The mixture is then cooled to 0° C., the pH is adjusted to 10 with a 30% aqueous NaOH-solution and it is stirred for 1 hour. The methanol is distilled off and the remaining aqueous solution is diluted with water and extracted with t-butyl methylether. The aqueous phase is acidified with concentrated HCl-solution and the resulting yellow suspension is filtered and washed with water. The solid is dried in vacuo at 100° C. to give 28.3 g (67%) of 2-amino-5-nitro-4-trifluoromethyl-benzoic acid, m.p. 237° C.

Provenance & Evidence