Doebner–Miller reaction

Doebner–Miller reaction refers to an organic chemical reaction that involves the condensation of quinolines with aldehydes in the presence of a strong acid to produce substituted quinolines. This reaction is named after the German chemists Oskar Doebner (1850–1907) and A. W. Miller who first reported it in 1883. The Doebner–Miller reaction is an important method for the synthesis of quinoline derivatives, which are valuable compounds in the pharmaceutical and dye industries.

Reaction Mechanism

The Doebner–Miller reaction mechanism involves the formation of an intermediate adduct between the quinoline and the aldehyde, facilitated by the acid catalyst. This adduct then undergoes a series of rearrangements and dehydration steps to yield the substituted quinoline. The choice of acid catalyst, typically a strong acid like sulfuric acid or hydrochloric acid, is crucial for the success of the reaction.

Applications

Substituted quinolines produced through the Doebner–Miller reaction have found extensive applications in various fields. In the pharmaceutical industry, these compounds are used in the synthesis of drugs with antimalarial, antibacterial, and antifungal properties. Additionally, quinoline derivatives are also employed in the manufacture of dyes, agrochemicals, and organic light-emitting diodes (OLEDs).

Variations

Several variations of the Doebner–Miller reaction have been developed to improve its efficiency and broaden its applicability. These include modifications in the choice of catalysts, reaction conditions, and starting materials. For instance, the use of Lewis acids as catalysts has been explored to facilitate the reaction under milder conditions.

See Also

• Quinoline
• Aldehyde
• Sulfuric acid
• Hydrochloric acid
• Lewis acids and bases