[CH2:1]([O:3][C:4]1[CH:5]=[C:6]([C:13]2[O:17][N:16]=[C:15]([C:18]3[CH:19]=[CH:20][C:21]4[O:25][C:24]([CH2:26][OH:27])=[CH:23][C:22]=4[CH:28]=3)[N:14]=2)[CH:7]=[CH:8][C:9]=1[O:10][CH2:11][CH3:12])[CH3:2]>O1CCOCC1.O=[Mn]=O>[CH2:1]([O:3][C:4]1[CH:5]=[C:6]([C:13]2[O:17][N:16]=[C:15]([C:18]3[CH:19]=[CH:20][C:21]4[O:25][C:24]([CH:26]=[O:27])=[CH:23][C:22]=4[CH:28]=3)[N:14]=2)[CH:7]=[CH:8][C:9]=1[O:10][CH2:11][CH3:12])[CH3:2]A suspension of the product of Step D (0.13 g; 0.34 mmol) and MnO2 (0.15 g; 1.7 mmol) in dioxane (4 ml) was refluxed for 1 h with stirring. After cooling to room temperature, the insoluble material was removed by filtration, washed with EtOAc (20 ml) and combined filtrates were evaporated to dryness to give the title compound (0.13 g; 100%), as greyish solid. 1H-NMR (CDCl3) 9.91 (s, 1H); 8.59 (s, 1H); 8.33 (dd, 1H, J=2, 9 Hz); 7.63-7.82 (m, 4H); 6.99 (d, 1H, J=9 Hz); 4.14-4.26 (m, 4H); 1.4-1.57 (m, 6H+H2O).
Wird geladen…