Reaction Steps
To a solution of 3-(3-cyclopropylmethoxy-4-difluoromethoxy-phenyl)-3-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-propionic acid (1.1 g, 2.6 mmol) in tetrahydrofurane was added carbonyldiimidazole (0.73 g, 4.5 mmol) at room temperature. The solution was stirred for 2 hours at room temperature. To the mixture was added hydroxylamine HCl salt (0.4 g, 2.3 mmol). The resulted mixture was stirred at room temperature for 4 hours. Water (20 ml) was added to the reaction mixture. THF was removed in vacuo and the resulted mixture was taken up in ethyl acetate (30 ml). The mixture was washed with saturated sodium bicarbonate solution (3×20 ml), water (20 ml) and brine (20 ml). The organic layer was dried over magnesium sulfate, filtered and concentrated in vacuo. The resulted oil was purified by silica gel chromatography (ethyl acetate:hexane=2:1) to give 3-(3-cyclopropylmethoxy-4-difluoromethoxy-phenyl)-3-(1,3-dioxo-1,3-dihydro-isoindol-2-yl)-N-hydroxy-propionamide as a white solid (700 mg, 61%): mp 129–131° C.; 1HNMR (DMSO-d6): δ 0.33–0.35 (m, 2H), 0.54–0.57 (m, 2H), 1.15–1.30 (m, 1H), 3.11 (d, J=5 Hz, 2H), 3.87 (d, J=7.5 Hz, 2H), 5.71 (t, J=7.5 Hz, 1H), 6.95–6.98 (m, 1H), 7.03 (t, JH-F=75 Hz, 1H), 7.11–7.17 (m, 2H), 7.85 (s, 4H), 8.80 (s, 1H), 10.60 (s, 1H). 13C NMR (CDCl3): δ 0.7, 3.9, 3.9, 10.8, 35.7, 52.0, 74.6, 112.6, 114.9, 116.7, 120.8, 120.9, 123.6, 124.2, 132.3, 135.00, 137.7, 140.9, 151.3, 169.0; Anal. Calcd. for C22H20F2N2O6: C, 59.19; H, 4.52; N, 6.28. Found: C, 58.98; H, 4.41; N, 6.16.
