[O:1]=[S:2]1(=[O:32])[C:6]2[CH:7]=[CH:8][CH:9]=[CH:10][C:5]=2[C:4]([S:11][CH:12]([CH2:17][C:18]2[CH:23]=[CH:22][C:21]([O:24][CH2:25][C:26]3[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=3)=[CH:20][CH:19]=2)[C:13]([O:15]C)=[O:14])=[N:3]1.[OH-].[K+].Cl.O>CO.O>[O:32]=[S:2]1(=[O:1])[C:6]2[CH:7]=[CH:8][CH:9]=[CH:10][C:5]=2[C:4]([S:11][CH:12]([CH2:17][C:18]2[CH:23]=[CH:22][C:21]([O:24][CH2:25][C:26]3[CH:27]=[CH:28][CH:29]=[CH:30][CH:31]=3)=[CH:20][CH:19]=2)[C:13]([OH:15])=[O:14])=[N:3]1The crude product from Step A was dissolved in a MeOH/H2O mixture (2:1, 4 ml). 0.7 g KOH was added to the solution and heated at reflux for 1.5 h. Then the reaction mixture was neutralized with 1M HCl, a small amount of water was added and the mixture extracted with ethyl acetate. The solvent was evaporated. The product was purified by chromatography (SiO2; ethyl acetate). The yield was 40%.
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