What are the three methods for refining and purifying quinolinone pharmaceutical intermediates? What are their characteristics?

The purification methods of quinolinone pharmaceutical intermediates generally include quinoline sulfonation and alkali melting, chloroquinoline hydrolysis, aminoquinoline hydrolysis and so on. Sulfonation and alkali melting of quinoline are mainly obtained by sulfonation and alkali melting of quinoline as raw material. However, the raw materials for chloroquinoline hydrolysis and aminoquinoline hydrolysis are difficult to obtain.