[CH3:1][O:2][N:3]=[C:4]([CH3:15])[CH2:5][C:6]1[C:11]([Cl:12])=[CH:10][C:9]([Cl:13])=[CH:8][C:7]=1[Cl:14].Cl.O.[OH-].[Na+]>CO>[CH3:1][O:2][NH:3][CH:4]([CH3:15])[CH2:5][C:6]1[C:7]([Cl:14])=[CH:8][C:9]([Cl:13])=[CH:10][C:11]=1[Cl:12]To 1-(2,4,6-trichloro-phenyl)-propan-2-one O-methyl-oxime prepared as described in example P4 (53.9 g; assay 99%; 0.20 mol) in methanol (100 g) was added hydrogen chloride gas (22.0 g; 0.60 mol), whereas internal temperature in maintained at 20-30° C. by external cooling. A colourless suspension was obtained. The reaction mixture was cooled to 15° C. and triethylamino borane (borane triethylamine complex; 27.6 g; assay 96%; 0.23 mol) was dosed in during 60 min maintaining internal temperature at 15° C. The reaction mass was stirred for another 2 hours allowing the mixture to warm to ambient temperature. Thereafter almost no starting material can be detected by HPLC. The reaction mixture was then added to preheated (85° C.) water (126 g) during 30 min. A steady stream of gas was evolved; at the same time solvent was distilled. Heating was continued and the temperature maintained at 85-90° C. for another 1 hour. Finally gas was no longer produced. The resulting mixture was cooled to 20-25° C. Sodium hydroxide (30% aqueous solution; 56.5 g; 0.42 mol) was carefully added in order to bring pH to 7.2-7.7. The resulting mixture was extracted with tert-butyl methyl ether (125 ml). Phases were allowed to separate. The (lower) aqueous phase was split of. The (upper) organic phase was washed with water (2×100 g) and evaporated. Crude O-Methyl-N-[1-methyl-2-(2,4,6-trichloro-phenyl)-ethyl]-hydroxylamine (53.9 g; assay 97.8%; yield 98.0%) was obtained as clear oil.
読み込み中…
