Hydrochloric Acid → 2-Amino-5-(trifluoromethyl)benzoic acid hydrochloride

Participants

Reaction Steps

Preparation D3, Step 1: A suspension of 2-(tert-butoxycarbonylamino)-5-(trifluoromethyl)benzoic acid (56.34 g, 185 mmol, see: S. Takagishi, et al., Synlett 1992) in dioxane (100 mL) was treated with the dropwise addition of 4 N hydrochloric acid solution in dioxane (250 mL, 1.0 mol), and the mixture was stirred for 4 h. Analysis by LC/MS indicated that the reaction was not complete, so additional 4 N hydrochloric acid solution in dioxane (250 mL, 1.0 mol) was added, and the mixture was stirred overnight. Analysis by LC/MS indicated that the reaction still contained c. 5% of the starting material, so additional 4 N hydrochloric acid solution in dioxane (100 mL, 0.4 mol) was added, and the mixture was stirred for 4 h. Analysis by LC/MS indicated that the reaction was now complete. The mixture was concentrated in-vacuo, and the residue was stripped 2× from methylene chloride to remove any remaining HCl. The 2-amino-5-(trifluoromethyl)benzoic acid, hydrochloride thus obtained was used immediately in the next step. MS (ES+)=206 (M+H+).

Provenance & Evidence