Acetic Anhydride → (2-Acetylamino-4-trifluoromethylphenyl)-acetic acid methyl ester

Participants

Reaction Steps

Hydrogenation and acetylation of (2-nitro-4-trifluoromethylphenyl)-acetic acid methyl ester (25 g, 0.095 mol) in the presence of 5% Pd—C (2.5 g, 50% wet) and acetic anhydride (38 g, 0.37 mol) in toluene (200 mL) was carried out under vigorous stirring at room temperature and atmospheric pressure for about 4-5 h (reaction monitored by TLC). The catalyst was removed by filtration and washed with toluene two times. The combined organics were evaporated in vacuo to yield the product (24.8 g, 95%), which was used without further purification in the next step. A small sample was crystallized from hexane to yield the product as a yellow solid, mp 92-94° C. 1H NMR (CDCl3) 8.86 (s, 1H), 8.21 (s, 1H), 7.36 (d, J=8.1 Hz, 1H), 7.31 (d, J=8.1 Hz, 1H), 3.74 (s, 3H), 3.68 (s, 2H), 2.23 (s, 3H).

Provenance & Evidence