Sodium Hydroxide → 5-((2'-oxo-6H-spiro[benzofuro[6,5-d][1,3]dioxole-7,3'-indoline]-1'-yl)methyl)-2-(trifluoromethyl)furan-3-carboxylic acid

Participants

Reaction Steps

To a solution of ethyl 5-[(2′-oxospiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-1′(2′H)-yl)methyl]-2-(trifluoromethyl)furan-3-carboxylate (1.30 g, 2.59 mmol) in ethanol (8 mL) and water (1.7 mL) was added sodium hydroxide (0.12 g, 3.00 mmol). The reaction mixture was heated at reflux for 45 min, concentrated in vacuo to remove ethanol. To the residue was added water (15 mL) and the mixture was acidified to pH˜3 by 10% hydrochloric acid at 0° C. The resulting mixture was extracted with ethyl acetate (3×50 mL). The organic layer was washed with water and brine, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated in vacuo to give 5-((2′-oxo-6H-spiro[benzofuro[6,5-d][1,3]dioxole-7,3′-indoline]-1′-yl)methyl)-2-(trifluoromethyl)furan-3-carboxylic acid (1.03 g, 84%): mp 195-197° C.; 1H NMR (300 MHz, DMSO-d6) δ 7.13-7.26 (m, 1H), 7.17-7.15 (m, 2H), 7.05-7.00 (m, 2H), 6.67 (s, 1H), 6.09 (s, 1H), 5.90-5.88 (m, 2H), 5.11-4.96 (m, 2H), 4.80-4.66 (m, 2H); 13C NMR (75 MHz, DMSO-d6) δ 177.0, 161.9, 155.8, 152.3, 148.9, 142.2, 141.9, 141.5, 132.1, 129.3, 124.1, 123.8, 122.2, 120.6, 120.1, 117.0, 111.8, 109.7, 103.1, 101.9, 93.8, 80.1, 57.9, 36.7; MS (ES−) m/z 472.0 (M−1).

Provenance & Evidence