C([O:8][C:9]1[CH:10]=[C:11]([O:16][S:17]([C:20]2[CH:25]=[CH:24][CH:23]=[CH:22][C:21]=2[Cl:26])(=[O:19])=[O:18])[CH:12]=[C:13]([CH3:15])[CH:14]=1)C1C=CC=CC=1>[Pd].O1CCCC1>[OH:8][C:9]1[CH:10]=[C:11]([O:16][S:17]([C:20]2[CH:25]=[CH:24][CH:23]=[CH:22][C:21]=2[Cl:26])(=[O:19])=[O:18])[CH:12]=[C:13]([CH3:15])[CH:14]=1A mixture of 2-chlorobenzenesulfonic acid 3-benzyloxy-5-methylphenyl ester (4.66 g, 12 mmol), as prepared in the preceding step, and 10% palladium on carbon (500 mg) in tetrahydrofuran (80 mL) was hydrogenated (balloon) for 3 h. The catalyst was removed by filtration through diatomaceous earth (tetrahydrofuran washes) and the filtrate was concentrated in vacuo. The residue was purified by flash column chromatography (methylene chloride) to give the title compound as a pale-yellow solid (3.20 g, 89%, 1 H-NMR (300 MHz, CDCl3) δ 2.22 (s, 3H), 5.24 (s, 1H), 6.44 (t, 1H), 6.53 (d, 2H), 7.38 (dt, 1H), 7.60 (m, 2H), 7.96 (dd, 1H).
Wird geladen…