[NH2:1][C:2]1[CH:11]=[CH:10][C:5]([C:6]([O:8][CH3:9])=[O:7])=[CH:4][C:3]=1[I:12].[C:13]1(=O)[CH2:17][CH2:16][CH2:15][CH2:14]1.S([O-])([O-])(=O)=O.[Na+].[Na+].C(O[BH-](OC(=O)C)OC(=O)C)(=O)C.[Na+].C(=O)(O)[O-].[Na+]>C(O)(=O)C>[CH:13]1([NH:1][C:2]2[CH:11]=[CH:10][C:5]([C:6]([O:8][CH3:9])=[O:7])=[CH:4][C:3]=2[I:12])[CH2:17][CH2:16][CH2:15][CH2:14]1
A mixture of methyl 4-amino-3-iodobenzoate from above (27.69 g, 100 mmol), cyclopentanone (52.8 mL, 600 mmol), and anhydrous sodium sulfate (1000 g, 142 mmol) in 500 mL of glacial acetic acid was stirred for two hours. Solid sodium triacetoxyborohydride (76.92, 345 mmol) was added in portions and stirred for 16 hrs at room temperature. The mixture was poured on to cool 900 mL of saturated aqueous sodium bicarbonate solution carefully and extracted with 150 mL (3×) of ethyl acetate. The ethyl acetate fraction was dried and evaporated. Purification with silica gel and 0.5% ethyl acetate in hexane gave 24 g (70%).
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