S(=O)(=O)(O)O.[CH3:6][O:7][C:8]([C:10]1[S:14][C:13]([CH2:15][CH:16]([C:18]2[C:19]([CH2:24][CH2:25][CH2:26][CH3:27])=[N:20][O:21][C:22]=2[CH3:23])O)=[N:12][C:11]=1[CH3:28])=[O:9].[OH-].[Na+]>C(OCC)(=O)C>[CH3:6][O:7][C:8]([C:10]1[S:14][C:13](/[CH:15]=[CH:16]/[C:18]2[C:19]([CH2:24][CH2:25][CH2:26][CH3:27])=[N:20][O:21][C:22]=2[CH3:23])=[N:12][C:11]=1[CH3:28])=[O:9]Concentrated sulfuric acid (85 mL) was added to 2-[2-(3-butyl-5-methyl-isoxazol-4-yl)-2-hydroxy-ethyl]-4-methyl-thiazole-5-carboxylic acid methyl ester (9.0 g, 26.6 mmol) then the mixture was heated at 90° C. for 2 h. The solution was carefully dropped into 2N sodium hydroxide (1580 mL) and ethyl acetate (100 mL) saturated sodium bicarbonate was added until pH 10 was reached. The reaction mixture was extracted with ethyl acetate then the combined organic extracts were dried, filtered and concentrated, to give the title compound (8.02 g, 94%) as a yellow oil that was used directly without further purification. MS: m/e=321.2 [M+H]+.
読み込み中…
