[CH3:1][O:2][C:3](=[O:16])[NH:4][C:5]1[O:6][C:7]2[CH:13]=[CH:12][CH:11]=[C:10]([O:14][CH3:15])[C:8]=2[N:9]=1.C([O-])(=O)C.[Na+].[I:22]Cl>C(O)(=O)C>[CH3:1][O:2][C:3](=[O:16])[NH:4][C:5]1[O:6][C:7]2[C:13]([I:22])=[CH:12][CH:11]=[C:10]([O:14][CH3:15])[C:8]=2[N:9]=1To a stirred solution of 40 g (18 mmol) (4-methoxy-benzooxazol-2-yl)-carbamic acid methyl ester and 4.4 g (54 mmol) sodium acetate in 20 ml acetic acid at room temperature was added dropwise 8.8 g (54 mmol) iodine monochloride and stirring continued for 30 h. The mixture was then poured onto water and extracted three times with ethyl acetate. The combined organic phases were washed with 1 M aqueous sodium thiosulphate solution, then dried over sodium sulfate and concentrated in vacuo. Trituration in ether afforded 4.1 g (65%) (7-iodo-4-methoxy-benzooxazol-2-yl)-carbamic acid methyl ester as a white crystalline solid. ES-MS m/e (%): 349 (M+H+, 100).
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