[CH3:1][O:2][C:3](=[O:27])[C@H:4]([NH:16]C(OCC1C=CC=CC=1)=O)[CH2:5][C:6]1[CH:15]=[CH:14][C:9]2[NH:10][C:11](=[O:13])[O:12][C:8]=2[CH:7]=1.C(=O)(O)[O-].[Na+]>C(O)=O.CO.[Pd].C(OCC)(=O)C.C1(C)C=CC=CC=1.C(O)C>[CH3:1][O:2][C:3](=[O:27])[C@H:4]([NH2:16])[CH2:5][C:6]1[CH:15]=[CH:14][C:9]2[NH:10][C:11](=[O:13])[O:12][C:8]=2[CH:7]=1A solution of (R)-2-benzyloxycarbonylamino-3-(2-oxo-2,3-dihydro-benzooxazol-6-yl)-propionic acid methyl ester (310 mg) in 4.4% formic acid in methanol (20 ml, freshly prepared in degassed methanol) was added via cannula to a suspension of 10% palladium on charcoal in 4.4% formic acid in methanol (20 ml, freshly prepared in degassed methanol). The resulting mixture was stirred at room temperature for 4 h. After filtration through a pad of celite, the solvents were removed in vacuo giving a tan solid. The solid was dissolved in a mixture of ethyl acetate (50 mL), toluene (10 mL) and ethanol (40 ml), and solid sodium bicarbonate (3.1 g) was added. The mixture was stirred at room temperature for 2 h and filtered. Solvents were removed in vacuo to afford the title compound. 1H-NMR (CD3OD, 500 MHz) δ 8.41 (br s, 2H), 7.17 (s, 1H), 7.09 (br s, 2H), 4.32 (s, 1H), 3.83 (s, 3H), 3.33 (s, 1H), 3.30 (s, 1H), 3.22 (s, 1H). Mass spec.: 237.20 (MH)+.
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