4-(5-Methoxy-benzofuran-2-yl)-3-methyl-phenol → 2-(4-Hydroxy-2-methyl-phenyl)-benzofuran-5-ol
Reaktionsgleichung
C[O:2][C:3]1[CH:4]=[CH:5][C:6]2[O:10][C:9]([C:11]3[CH:16]=[CH:15][C:14]([OH:17])=[CH:13][C:12]=3[CH3:18])=[CH:8][C:7]=2[CH:19]=1.N1C(=O)CC[C@H]1C(O)=O.Cl>>[OH:17][C:14]1[CH:15]=[CH:16][C:11]([C:9]2[O:10][C:6]3[CH:5]=[CH:4][C:3]([OH:2])=[CH:19][C:7]=3[CH:8]=2)=[C:12]([CH3:18])[CH:13]=1Komponenten
3
Reaktionsbedingungen
- Temperatur
- 180 °C
Versuchsvorschrift
A mixture of the monomethyl ether 79 (0.27 g, 1.1 mmol) and Pyr-HCl was heated at 180° C. for 30–45 minutes. The reaction mixture was allowed to cool and partitioned between EtOAc and 2 N HCl aq and the EtOAc was washed with brine and dried over MgSO4. The solution was filtered, concentrated and chromatographed on silica gel (EtOAc/hexanes 1:3): Mp=167–169° C.; 1H NMR (DMSO-d6) δ 8.61 (s, 1 H), 8.11 (s, 1 H), 7.67 (d, 1 H, J=8.9 Hz), 7.33 (d, 1 H, J=8.7 Hz), 7.02 (d, 1 H, J=2.4 Hz), 6.82–6.78 (m, 4H (overlapping protons)), 2.50 (s, 3 H); MS 239 (M−H)−.