C[O:2][C:3](=[O:21])[CH2:4][CH2:5][CH2:6][CH2:7][C:8]1[O:9][C:10]([C:13]2[CH:18]=[CH:17][CH:16]=[CH:15][C:14]=2[O:19][CH3:20])=[CH:11][N:12]=1.[Li+].[OH-].Cl>O1CCOCC1.O>[CH3:20][O:19][C:14]1[CH:15]=[CH:16][CH:17]=[CH:18][C:13]=1[C:10]1[O:9][C:8]([CH2:7][CH2:6][CH2:5][CH2:4][C:3]([OH:21])=[O:2])=[N:12][CH:11]=1Dissolve 5-[5-(2-methoxy-phenyl)-oxazol-2-yl]-pentanoic acid methyl ester (2.47 g, 8.54 mmol) in 40 mL of dioxane and add a solution of LiOH (1.0344 g, 43.19 mmol) in 20 mL of water to the solution. Allow the reaction to stir at ambient temperature for 21 hours. Acidify the reaction with 5N HCl and concentrate the reaction mixture in vacuo to remove the dioxane. Extract the aqueous residue with EtOAc (3×). Dry the combined organic layers with MgSO4. Filter off the drying agent and concentrate in vacuo to afford a crude residue. Recrystallize the residue in EtOAc/hexanes to afford 1.7692 g of the titled product (75%): mass spectrum: m/z=276.1 (M+H).
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