Knorr Quinoline Synthesis

The synthesis of 2‐hydroxyquinolines via the cyclization and dehydration of an anilide intermediate condensed from β‐ketoesters and anilines at a relatively high temperature is generally known as Knorr quinoline synthesis. In contrast, a similar reaction between anilines and β‐ketoesters but at low temperatures has also been reported. The study finds that the formation of an alkyl crotonate and anilide intermediate during the reaction is temperature dependent.