Water → HCID 22452954, compound

Participants

Reaction Steps

Homophthalic acid (1.00 g, 5.55 mmol) dissolved in trifluoroacetic anhydride (7.8 ml) was heated in a sealed tube for 24 h at 110° followed by a further 24 h at 140°. The reaction was poured into water (100 ml), left for 1 h and the resulting precipitate extracted into EtOAc (3×50 ml). The EtOAc solution was dried (MgSO4) and the solvent removed under reduced pressure to give a pale brown solid. LCMS showed these to be a 9:1 mixture of −1-oxo-3-(trifluoromethyl)-1H-isochromene-4-carboxylic acid. m/z (ES+, 70V) 259 (MH+) and 3-Trifluoromethyl)-1H-isochrom-1-one m/z (ES+, 70V) 215 (MH+). The solids were dissolved in concentrated ammonium hydroxide (70 ml) and heated for 4 days at 100°, an additional 10 ml of concentrated ammonium hydroxide added after 24 h. The solution was allowed to cool to room temperature, the precipitate removed by filtration and the filtrate extracted with EtOAc (1×50 ml). The EtOAc was dried (MgSO4). the solvent removed under reduced pressure, and the resulting yellow solids combined with the precipitated material, to give the title compound 825 mg, 70%. δH (CDCl3) 8.48 (1H, d, J 7.5 Hz), 7.77 (1H, t), 7.68 (2H, m), 6.95 (1H, s); m/z (ES+, 70V), 215 (MH+).

Provenance & Evidence