Skatole


Skatole or 3-methylindole is an organic compound belonging to the indole family. Occurring in high concentrations, it is the primary odor of feces. In low concentrations, it has a flowery smell and is found in several flowers and essential oils, including those of orange blossoms, jasmine, and Ziziphus mauritiana.
It is used as a fragrance and fixative in many perfumes and as an aroma compound. Its name derives from the Greek root skato-, meaning "feces". Skatole was discovered in 1877 by the German physician Ludwig Brieger.

Biosynthesis, chemical synthesis, and reactions

Skatole is derived from the amino acid tryptophan in the mammalian digestive tract. Tryptophan is converted to indoleacetic acid, which decarboxylates to give the methylindole.
Skatole can be synthesized via the Fischer indole synthesis.
It gives a violet color upon treatment with potassium ferrocyanide.

Insect attractant

Skatole is one of many compounds that are attractive to males of various species of orchid bees, which apparently gather the chemical to synthesize pheromones; it is commonly used as bait for these bees for study. It is also known for being an attractant for the Tasmanian grass grub beetle.
Skatole has been shown to be an attractant to mosquitoes in both field and laboratory conditions. Because this compound is present in feces, it is found in combined sewage overflows as streams and lakes containing CSO water have untreated human and industrial waste. CSO sites are thus of particular interest when studying mosquito-borne diseases such as West Nile virus.

Animal studies

Skatole has been shown to cause pulmonary edema in goats, sheep, rats, and some strains of mice. It appears to selectively target club cells, which are the major site of cytochrome P450 enzymes in the lungs. These enzymes convert skatole to a reactive intermediate, 3-methyleneindolenine, which damages cells by forming protein adducts.
With the testicular steroid androstenone, skatole is regarded as a principal determinant of boar taint.
It contributes to bad breath.

Application

Skatole is the starting material in the synthesis of atiprosin.