Paal-Knorr pyrrole synthesis

What is Paal-Knorr pyrrole synthesis?

Paal-Knorr synthesis is a group of organic chemical reactions in which a 1,4-diketone is converted into a pyrrole through the condensation of the diketone with an amine in the presence of an acid catalyst. The reactions were discovered by the Hungarian chemists Julius Paal and Wilhelm Knorr in the late 19th century and are named after them..

Paal-Knorr pyrrole synthesis
Paal-Knorr pyrrole synthesis

There are several different variations of the Paal-Knorr synthesis, including the Paal-Knorr pyrrole synthesis, the Paal-Knorr furan synthesis, and the Paal-Knorr thiophene synthesis, which are used to synthesize pyrroles, furans, and thiophenes, respectively..

One of the key features of the Paal-Knorr synthesis is that it allows for the synthesis of aromatic compounds, which are important intermediates in a wide range of chemical reactions. Aromatic compounds are also useful as starting materials for the synthesis of other compounds, such as dyes and pharmaceuticals..

Paal-Knorr synthesis can be performed under a variety of conditions, including both acidic and basic conditions. The choice of conditions depends on the specific reactants and desired product, and can be influenced by factors such as the stability of the intermediate and the ability to control the regiochemistry of the reaction..


Paal-Knorr synthesis is a useful tool for synthesizing aromatic compounds and has a wide range of applications in the field of organic chemistry..


  • Paal, C. (1885), Synthese von Thiophen- und Pyrrolderivaten. [Synthesis of thiophene and pyrrole derivatives.] Ber. Dtsch. Chem. Ges., 18: 367-371.
  • Knorr, L. (1885), Einwirkung des Diacetbernsteinsäureesters auf Ammoniak und primäre Aminbasen. [Action of the diacetate succinic acid ester on ammonia and primary amine bases.] Ber. Dtsch. Chem. Ges., 18: 299-311.