Skraup Synthesis

Skraup synthesis

[skrau̇p ′sin·thə·səs]
(organic chemistry)
A method for the preparation of commercial synthetic quinoline by heating aniline and glycerol in the presence of sulfuric acid and an oxidizing agent to form pyridine unsubstituted quinolines.

Skraup Synthesis

 

the synthesis of quinoline and quinoline analogues and derivatives by the reaction of aniline (I) (or aniline’s corresponding analogues and derivatives) with glycerine in the presence of a dehydrating agent (usually sulfuric or phosphoric acid) and an oxidizing agent (usually nitrobenzene or a derivative of nitrobenzene corresponding to a particular aniline derivative). Under the action of the dehydrating agent, glycerine is converted to acrolein (II), which then participates in the main reaction:

where X designates an organic radical, a halogen, or a group such as—NO2.

The reaction was discovered in 1880 by Z. H. Skraup. It is used in the laboratory and in industry for the synthesis of pharmaceutical preparations and photosensitizers.