CS([Cl:5])(=O)=O.[Cl-].[Li+].[CH3:8][C:9]1[CH:14]=[C:13]([CH3:15])[CH:12]=[C:11]([CH3:16])[C:10]=1[S:17]([O:20][C:21]1[C:26]([CH2:27][C:28]2[CH:33]=[CH:32][C:31]([CH2:34]O)=[CH:30][C:29]=2[O:36][CH3:37])=[C:25]([CH3:38])[N:24]=[C:23]([NH2:39])[N:22]=1)(=[O:19])=[O:18]>C1COCC1.O>[CH3:8][C:9]1[CH:14]=[C:13]([CH3:15])[CH:12]=[C:11]([CH3:16])[C:10]=1[S:17]([O:20][C:21]1[C:26]([CH2:27][C:28]2[CH:33]=[CH:32][C:31]([CH2:34][Cl:5])=[CH:30][C:29]=2[O:36][CH3:37])=[C:25]([CH3:38])[N:24]=[C:23]([NH2:39])[N:22]=1)(=[O:19])=[O:18]Methanesulfonyl chloride (1.4 mL) was added to a mixture of lithium chloride (0.74 g) and the product from step (iv) (4.0 g) in THF (45 mL). The mixture was stirred at RT for 1.5 h, diluted with water and extracted with EtOAc. The combined organic layer was washed with brine, dried and concentrated under reduced pressure to afford the crude product as a pale yellow oil, which was used for next reaction without further purification; 1H NMR (300 MHz, CDCl3); 6.91 (2H, s), 6.83 (1H, s), 6.81-6.74 (2H, m), 4.69 (2H, br s), 4.54 (2H, s), 3.82 (3H, s), 3.80 (2H, s), 2.54 (6H, s), 2.29 (3H, s), 2.24 (3H, s).
Loading…