反应详情

温度

20 °C

2 drops of dimethylformamide are added to a solution, at 20° C., of 2-methoxyimino-3-oxo-butyric acid (syn isomer) (4.08 g) in diethyl ether (50 cc), and oxalyl chloride (2 cc) dissolved in ethyl ether (5 cc) is then added dropwise in the course of 15 minutes. The mixture is stirred for 1 hour at 20° C., a further drop of dimethylformamide is added, and the reaction is continued for 15 minutes. The mixture is then concentrated to dryness at 20° C. under 20 mm Hg (2.7 kPa) and the residue is taken up in petroleum ether (2×30 cc), the solvent being evaporated off, each time, at 20° C. under 20 mm Hg (2.7 kPa). The 2-methoxyimino-3-oxo-butanoyl chloride (syn isomer) thus obtained is dissolved in methylene chloride (50 cc), and a 5.4 N solution of hydrogen chloride in ether (0.2 cc), and bromine (1.14 cc) are added to this solution at 20° C. The mixture is stirred for 20 hours at 20° C. and is then concentrated to dryness at 20° C. under 20 mm Hg (2.7 kPa), and a brown oil consisting principally of 4-bromo-2-methoxyimino-3-oxo-butyryl chloride (syn isomer) (5.42 g) is obtained.

1. additionis then added dropwise in the course of 15 minutes
2. waitthe reaction is continued for 15 minutes
3. concentrationThe mixture is then concentrated to dryness at 20° C. under 20 mm Hg (2.7 kPa)
4. customthe solvent being evaporated off
5. customat 20° C.