Скачать или смотреть Skraup’s Synthesis of Quinoline

Definition: The Skraup Synthesis is a classic chemical reaction used to synthesize quinoline by heating an aniline (or substituted aniline) with glycerol in the presence of sulfuric acid and an oxidizing agent.
Key Reagents:Aniline: The primary aromatic amine starting material. Glycerol: Dehydrates to form acrolein, the key intermediate. Sulfuric Acid (\: Acts as both a dehydrating agent and a catalyst. Oxidizing Agent: Typically nitrobenzene, arsenic pentoxide, or ferric oxide to aromatize the intermediate. Moderating Agent: Ferrous sulfate is often added to control the otherwise violent and exothermic nature of the reaction
Step-by-Step Mechanism
Dehydration: Glycerol is dehydrated by sulfuric acid to produce acrolein (2-propenal).
Michael Addition: Aniline performs a nucleophilic conjugate addition to the acrolein.
Cyclization: The intermediate undergoes acid-catalyzed cyclization via electrophilic aromatic substitution.
Dehydration & Oxidation: The resulting cyclic intermediate is dehydrated and then oxidized by nitrobenzene to yield the final quinoline product.
Safety: The reaction is famously violent; use of a condenser and moderating agents like FeSO4 is critical in a lab setting.