反应详情

3.2 g (10 millimole) of 1-ethyl-6-fluoro-7-(1-piperazinyl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid was dissolved in 30 ml of acetic acid, and 1.4 g (20 millimole) of sodium nitrite was added slowly thereto at room temperature under stirring. After stirring for 30 minutes at room temperature, 50 ml of water was added. The precipitated crystals were collected by filtration, washed successively with water, ethanol and dichloromethane and dried. 3.5 g (quantitative) of 1-ethyl-6-fluoro-7-(4-nitroso-1-piperazinyl)-4-oxo-1,4-dihydroquinoline-3-carboxylic acid was obtained as grayish colorless powders.

1. stirringAfter stirring for 30 minutes at room temperature
2. filtrationThe precipitated crystals were collected by filtration
3. washwashed successively with water, ethanol and dichloromethane
4. customdried