Sulfuric Acid → (2-[3-Cyclopentyl-2-(4-nitro-phenyl)-propionylamino]-thiazol-4-yl}-acetic acid methyl ester
反応式
[CH2:1]([O:3][C:4](=[O:30])[CH2:5][C:6]1[N:7]=[C:8]([NH:11][C:12](=[O:29])[CH:13]([C:20]2[CH:25]=[CH:24][C:23]([N+:26]([O-:28])=[O:27])=[CH:22][CH:21]=2)[CH2:14][CH:15]2[CH2:19][CH2:18][CH2:17][CH2:16]2)[S:9][CH:10]=1)C.S(=O)(=O)(O)O>CO>[CH3:1][O:3][C:4](=[O:30])[CH2:5][C:6]1[N:7]=[C:8]([NH:11][C:12](=[O:29])[CH:13]([C:20]2[CH:25]=[CH:24][C:23]([N+:26]([O-:28])=[O:27])=[CH:22][CH:21]=2)[CH2:14][CH:15]2[CH2:16][CH2:17][CH2:18][CH2:19]2)[S:9][CH:10]=1参加物
4
実験手順
A solution of {2-[3-cyclopentyl-2-(4-nitro-phenyl)-propionylamino]-thiazol-4-yl }-acetic acid ethyl ester (prepared as in Example 23, 160 mg, 0.37 mmol) in methanol (10 mL) was treated with a catalytic amount of sulfuric acid. The reaction mixture was heated under reflux for 68 h. The reaction was concentrated in vacuo. Flash chromatography (Merck Silica gel 60, 230-400 mesh, 75/25 hexanes/ethyl acetate) afforded {2-[3-cyclopentyl-2-(4-nitro-phenyl)-propionylamino]-thiazol-4-yl}-acetic acid methyl ester (82.3 mg, 53.3%) as a pale yellow oil: FAB-HRMS m/e calcd for C20H23N3O5S (M+H)+ 418.1436, found 418.1424.