Willgerodt rearrangement

Willgerodt-Kindler Reaction

The Willgerodt-Kindler Reaction is a chemical reaction that involves the transformation of aryl alkyl ketones into corresponding amides through the rearrangement process. This reaction is significant in organic chemistry for the synthesis of various amides, which are pivotal in the development of pharmaceuticals and other organic compounds. The reaction is named after the German chemists Curt Willgerodt and Max Kindler, who first reported it in the late 19th and early 20th centuries, respectively.

Reaction Mechanism

The Willgerodt-Kindler Reaction proceeds through the reaction of an aryl alkyl ketone with sulfur and an amine, typically morpholine or piperidine, under heating. The process involves the formation of a thioamide intermediate, which then undergoes rearrangement to produce the corresponding amide. The exact mechanism can vary depending on the substrates and conditions used, but it generally involves the formation of a carbon-sulfur bond followed by migration and hydrolysis steps.

Applications

The Willgerodt-Kindler Reaction has found applications in the synthesis of various amides, which are crucial in the pharmaceutical industry for the development of drugs. It is also used in the synthesis of heterocycles and other organic compounds that are of interest in material science and as intermediates in organic synthesis.

Variations

Several variations of the Willgerodt-Kindler Reaction have been developed to improve its efficiency, selectivity, and scope. These include modifications of the reaction conditions, such as the use of different solvents or catalysts, as well as the use of alternative sulfur sources. These variations have expanded the utility of the reaction in organic synthesis.

Limitations

Despite its utility, the Willgerodt-Kindler Reaction has some limitations. The reaction conditions can be harsh, and the yields may vary depending on the substrates used. Additionally, the reaction may not be suitable for substrates that are sensitive to the reaction conditions.

See Also

• Chemical reaction
• Organic synthesis
• Amide
• Aryl alkyl ketone
• Sulfur
• Morpholine
• Piperidine