O[Li].O.C([O:6][C:7](=[O:25])[CH2:8][CH2:9][CH2:10][CH2:11][C:12]1[CH:16]=[C:15]([C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][C:18]=2[O:23][CH3:24])[O:14][N:13]=1)C.Cl>O.O1CCOCC1>[CH3:24][O:23][C:18]1[CH:19]=[CH:20][CH:21]=[CH:22][C:17]=1[C:15]1[O:14][N:13]=[C:12]([CH2:11][CH2:10][CH2:9][CH2:8][C:7]([OH:25])=[O:6])[CH:16]=1Add a solution of LiOH.H2O (1.83 g, 43.5 mmol) in water (30 mL) to a rapidly stirred solution of 5-[5-(2-methoxy-phenyl)-isoxazol-3-yl]-pentanoic acid ethyl ester (2.64 g, 8.7 mmol) in dioxane (60 mL) and stir overnight at room temperature. After 1 hour, acidify to pH 1 with 5N HCl solution and concentrate to remove the majority of the dioxane. Partition residue between 20% i-PrOH/CHCl3 and 1N HCl solution and separate layers. Backextract from aqueous layer with 20% i-PrOH/CHCl3 and dry combined organic layers over MgSO4, and concentrate to get 2.5 grams of a yellow oil. Recrystallize from EtOAc/hexanes to afford the title compound (1.96 g, 82%). MS (IS) 276 (M+1)+.
読み込み中…
