[CH2:1]([O:4][C:5]1[CH:10]=[CH:9][C:8]([C:11]2[C:15]([C:16]([O:18]CC)=[O:17])=[C:14]([CH3:21])[O:13][N:12]=2)=[CH:7][CH:6]=1)[CH:2]=[CH2:3].C1COCC1.O.[Li+].[OH-]>C(OCC)(=O)C>[CH2:1]([O:4][C:5]1[CH:10]=[CH:9][C:8]([C:11]2[C:15]([C:16]([OH:18])=[O:17])=[C:14]([CH3:21])[O:13][N:12]=2)=[CH:7][CH:6]=1)[CH:2]=[CH2:3]
To the crude ethyl 3-(4-(allyloxy)phenyl)-5-methylisoxazole-4-carboxylate (Preparation D) (0.66 g) was added 10 ml of THF, 0.5 mL of water, and 0.240 g of LiOH. The resulted reaction mixture was stirred at room temperature overnight. Water (150 mL) and ethyl acetate (150 mL) were added to the reaction mixture. Layers were separated and the aqueous solution was acidified by addition of 20 mL of 1.4 N HCl. The product was then extracted from the acidic aqueous solution with ethyl acetate (2×150 mL). The combined extract was dried over anhydrous sodium sulfate. Solvent was evaporated to give 0.600 g of product. LCMS (method B) RT 3.00 min., MH+260. 1H NMR (500 MHz, CD3OD) δ 7.57 (d, J=8.5Hz, 2H), 6.99 (d, J=8.5Hz, 2H), 6.16-6.01 (m, 1H), 5.45-5.24 (m, 2H), 4.60 (d, J=4.9Hz, 2H), 2.70 (s, 3H).
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