Willgerodt reaction scope

The Willgerodt reaction is usually carried out under high pressure, thus requiring special laboratory equipment, while with the Kindler variant this is not necessary. The Kindler variant is of wider scope, and yields are generally better. In addition aromatic compounds with vinyl substituents may be employed as substrates instead of the ketone, e.g. styrene 7 ... 

Many other nitrogen- and sulfur-containing rings are available from reactions of the Willgerodt-Kindler type. Benzo- and pyridino-fused thia-zoles, for example, are formed from anilines (benzeneamines) and amino-pyridines, respectively.25 Asinger26 has reviewed the scope of these reactions in heterocyclic synthesis. 

Carlson, R. and Lundstedt, T. Scope of Organic Synthetic Reactions. Multivariate Methods for Exploring the Reaction Space. An example by the Willgerodt-Kindler Reaction. Acta Chem. Scand., 1987, B41, 164-173. 

Example Scope of the Willgerodt-Kindler reaction with regard to... 

This is not an example of solvent selection. It is given to show a selection of co-substrates from subgroups in the determination of the scope of a reaction, viz, amine variation in the Willgerodt-Kindler reaction. The general features of this reaction were discussed in Chapter 6. 

Reichardt (2003, p. 504) presents a table of solvents recommended as replacements for more hazardous ones. Total avoidance of solvent is sometimes a possibility. An example was mentioned in Chapter 1. Scott (2003) discusses the scope of solvent-free methods and considerations of mutual solubility of reactants and of control, including exothermic reactions. A recent application is the solvent-free synthesis by Valdez-Rojas et al. (2012) of thioamides and alpha-ketothioamides through the Willgerodt-Kindler reaction. Scheme B. 

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