[OH:1][C:2]1[C:7]2[O:8][C:9]3[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=3[C:6]=2[C:5]([CH:15]=[O:16])=[CH:4][CH:3]=1.C(=O)([O-])[O-].[K+].[K+].[CH2:23](Br)[C:24]1[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1>CN(C=O)C.O>[CH2:23]([O:1][C:2]1[C:7]2[O:8][C:9]3[CH:14]=[CH:13][CH:12]=[CH:11][C:10]=3[C:6]=2[C:5]([CH:15]=[O:16])=[CH:4][CH:3]=1)[C:24]1[CH:29]=[CH:28][CH:27]=[CH:26][CH:25]=1Intermediate 19 (1 gm, 5.10 mmol) was dissolved in dry DMF (10 ml). Anhydrous potassium carbonate (1.05 gm, 7.65 mmol) was added to the above solution and was stirred for 10 min. at 80° C. To this was added benzyl bromide (0.87 gm, 5.10 mmol) and the reaction mixture was stirred for 2 h. The reaction mixture was cooled to room temperature and diluted with water (100 ml) and extracted with ethyl acetate (3×50 ml). The organic extract was washed with water (50 ml) and brine solution (25 ml) and dried over anhydrous sodium sulfate. Removal of solvent gave the product as a brown solid (1.4 gm).
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