What Is Skatole?
Skatole, also known as 3-methylindole, is a heterocyclic aromatic compound with the chemical formula C9H9N. It is found in elm and camphor tree trunks, beetroots, excrement, and coal tar. In the human body, it is produced from the metabolism of tryptophan by intestinal bacteria and contributes to the odor of feces.
Skatole is a white crystal that turns brown over time, with a melting point of 95°C and a boiling point of 265°C. It is insoluble in water but soluble in alcohols, benzene, and ether. When it reacts with potassium ferricyanide and sulfuric acid, it turns purple.
Uses of Skatole
Skatole is used at low concentrations in cosmetic fragrances, where it imparts a floral scent. Notably, it is a component of the jasmine fragrance. In higher concentrations, it has an unpleasant odor but is perceived as a sweet, soft scent at lower levels. It is also used as a flavoring and additive in cigarettes.
Properties and Synthesis of Skatole
The molar mass of Skatole is 131.17 g/mol. It is synthesized through Fischer indole synthesis, which involves heating phenylhydrazone with an acid catalyst. This process can utilize sulfuric or hydrochloric acid, as well as Lewis acids like boron trifluoride diethyl ether complex and zinc chloride.
Related compounds to Skatole include various methylated indoles, such as 1-methylindole, 2-methylindole, and others, each with distinct chemical properties and applications.
Safety and Handling
Due to its strong odor and potential toxicity, Skatole should be handled with appropriate protective equipment in a well-ventilated laboratory environment. It is also a flammable substance and should be stored away from light to prevent decomposition.