N-bromobutanimide → methyl 4-(4-bromo-1-methyl-1H-pyrazol-5-yl)-5-ethyl-2-thiophenecarboxylate
反応式
[CH2:1]([C:3]1[S:7][C:6]([C:8]([O:10][CH3:11])=[O:9])=[CH:5][C:4]=1[C:12]1[N:16]([CH3:17])[N:15]=[CH:14][CH:13]=1)[CH3:2].[Br:18]N1C(=O)CCC1=O>O1CCCC1>[Br:18][C:13]1[CH:14]=[N:15][N:16]([CH3:17])[C:12]=1[C:4]1[CH:5]=[C:6]([C:8]([O:10][CH3:11])=[O:9])[S:7][C:3]=1[CH2:1][CH3:2]参加物
4
実験手順
A solution of methyl 5-ethyl-4-(1-methyl-1H-pyrazol-5-yl)-2-thiophenecarboxylate (1 g, 3.99 mmol) [prepared in Example 98] and N-bromosuccinimide (0.711 g, 3.99 mmol) in tetrahydrofuran (8 ml) was stirred in a sealed tube for 1 h at 70° C. The reaction mixture was partitioned between H2O-DCM and the aqueous phase was washed several times with DCM. The combined organic fractions were dried over Na2SO4, concentrated and purified by column chromatography (10-50% EtOAc in hexanes yielding methyl 4-(4-bromo-1-methyl-1H-pyrazol-5-yl)-5-ethyl-2-thiophenecarboxylate (1.2 g, 3.54 mmol, 89% yield) as an orange oil: LCMS (ES) m/e 329, 331 (M, M+2)+.