反应详情

温度

20 °C

Dimethylformamide (2 drops) is added to a solution, at 20° C., of 2-methoxyimino-3-oxo-butyric acid, syn isomer (4.08 g) in diethyl ether (50 cc), after which oxalyl chloride (2 cc) dissolved in diethyl ether (5 cc) is added dropwise in the course of 15 minutes. The mixture is stirred for 1 hour at 20° C., dimethylformamide (1 drop) is added again and the reaction is continued for 15 minutes. The mixture is 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 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 then concentrated to dryness at 20° C. under 20 mm Hg (2.7 kPa), and a brown oil (5.42 g) consisting principally of 4-bromo-2-methoxyimino-3-oxo-butyryl chloride, syn isomer, is obtained.

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