[C:1]([O:4][CH2:5][CH2:6][O:7][N:8]=[C:9]1[C:13](=O)[C:12]2[CH:15]=[CH:16][CH:17]=[CH:18][C:11]=2[O:10]1)(=[O:3])[CH3:2].Cl.[CH3:20][O:21][NH2:22].O>CN1CCCC1=O>[C:1]([O:4][CH2:5][CH2:6][O:7][N:8]=[C:9]1[C:13](=[N:22][O:21][CH3:20])[C:12]2[CH:15]=[CH:16][CH:17]=[CH:18][C:11]=2[O:10]1)(=[O:3])[CH3:2]10 g (0.04 mol) of 2-(3-oxo-3H-benzofuran-2-ylideneaminooxy)-ethyl acetate (XIV-1) and 4.18 g (0.05 mol) of O-methylhydroxylamine hydrochloride are dissolved in 40 ml of N-methyl-2-pyrrolidinone and stirred at 80° C. for 1 hour. The reaction mixture is poured into water and the resulting mixture is extracted with ethyl acetate. The organic phase is dried over sodium sulphate and the solvent is distilled off under reduced pressure. 10.6 g of crude 2-(3-methoxyimino-3H-benzofuran-2-ylideneaminooxy)-ethyl acetate (XIII-1) are obtained, which are chromatographed over silica gel using a mixture of tert-butyl methyl ether and petroleum ether (1:1). 6.9 g (59.1% of theory) of 2-(3-methoxyimino-3H-benzofuran-2-ylideneaminooxy)-ethyl acetate (XIII-1) having a content of 82.15% of stereoisomer A and 13.38% of stereoisomer B are obtained.
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