反应详情

To a suspension of 8-hydroxy-6-oxo-5,6-dihydro-pyrido[2,3-b]pyrazine-7-carboxylic acid methyl ester (Example 7.1) in 1,2-dichloro-ethane (9 ml) was added powdered molecular sieves (4A) followed by dropwise addition of isobutyryl chloride (0.048 ml). The reaction mixture was heated to reflux for 5 hours, cooled to ambient temperature and filtered. The filtrate was concentrated to give 8-isobutyryloxy-6-oxo-5,6-dihydro-pyrido[2,3-b]pyrazine-7-carboxylic acid methyl ester as a light brown solid (0.166 g) which was used without further purification.

1. additionwas added
2. temperatureThe reaction mixture was heated
3. temperatureto reflux for 5 hours
4. filtrationfiltered
5. concentrationThe filtrate was concentrated