[O:1]1[C:5]2[CH:6]=[CH:7][C:8]([CH:10]([C:33]3[CH:41]=[CH:40][C:36]4[O:37][CH2:38][O:39][C:35]=4[CH:34]=3)[CH:11]([NH:17][C:18](=[O:32])[CH:19]([C:26]3[CH:31]=[CH:30][CH:29]=[CH:28][CH:27]=3)[C:20]3[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=3)[C:12]([O:14]CC)=[O:13])=[CH:9][C:4]=2[O:3][CH2:2]1.[OH-].[Na+]>CO>[O:1]1[C:5]2[CH:6]=[CH:7][C:8]([CH:10]([C:33]3[CH:41]=[CH:40][C:36]4[O:37][CH2:38][O:39][C:35]=4[CH:34]=3)[CH:11]([NH:17][C:18](=[O:32])[CH:19]([C:20]3[CH:25]=[CH:24][CH:23]=[CH:22][CH:21]=3)[C:26]3[CH:27]=[CH:28][CH:29]=[CH:30][CH:31]=3)[C:12]([OH:14])=[O:13])=[CH:9][C:4]=2[O:3][CH2:2]1The ester of Example 20 (0.470 g, 0.85 mmol) is dissolved in 100 mL of methanol. The solution is treated with 4.5 mL of 1N aqueous sodium hydroxide and stirred under reflux for 6 hours. Another 4.5 mL of 1N sodium hydroxide is added and reflux is continued for 24 hours. The methanol is evaporated in vacuo and the residue is dissolved in water. The solution is washed with ether, acidified with 3N hydrochloric acid and extracted with ethyl acetate (3×50 mL). The organic phase is dried (magnesium sulfate), filtered, and evaporated to give 0.407 g (91%) of product as a white solid;
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