The trihydroxybenzenes (or benzenetriols) are organic compounds with the formula C6H3(OH)3. Also classified as polyphenols, they feature three hydroxyl groups substituted onto a benzene ring. They are white solids with modest solubility in water. The trihydroxybenzenes (or benzenetriols) are organic compounds with the formula C6H3(OH)3. Also classified as polyphenols, they feature three hydroxyl groups substituted onto a benzene ring. They are white solids with modest solubility in water. The enzyme pyrogallol hydroxytransferase uses 1,2,3,5-tetrahydroxybenzene and 1,2,3-trihydroxybenzene (pyrogallol), whereas its two products are 1,3,5-trihydroxybenzene (phloroglucinol) and 1,2,3,5-tetrahydroxybenzene. This enzyme can be found in Pelobacter acidigallici.