5hydroksylaatio

5-hydroksylaatio is a chemical transformation in which a hydroxyl group is introduced at the fifth position of a substrate. The term is commonly used in biochemistry and medicinal chemistry to describe regioselective hydroxylation at C-5 of aromatic rings or heterocycles, and may occur as part of drug metabolism or natural product biosynthesis.

In biological systems, 5-hydroksylaatio is typically carried out by monooxygenases, especially cytochrome P450 enzymes. These enzymes activate molecular oxygen and insert one oxygen atom into a C–H bond at the target position, yielding a C–OH group. Other enzymes, such as flavin-dependent monooxygenases, can also perform similar 5-position hydroxylations depending on the substrate.

A well-known example is the enzymatic conversion of tryptophan to 5-hydroxytryptophan by tryptophan hydroxylase, the first step in serotonin biosynthesis. In pharmacology, hydroxylation at the 5-position occurs on drugs and endogenous compounds, influencing activity, solubility, and clearance.

5-hydroksylaatio is exploited in drug development and metabolic studies to generate hydroxy metabolites, which can be further processed or studied for activity. In synthetic chemistry, it provides access to 5-hydroxy derivatives that serve as intermediates for natural products or pharmaceuticals. In microbial biosynthesis, engineered pathways can introduce hydroxyl groups at the 5-position of aromatic substrates.

See also: Hydroxylation, P450 enzymes, serotonin synthesis, 5-hydroxytryptophan.