3-Azidocoumarin is an

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

that is used in the area of bioconjugation. It is a derivative of

coumarin Coumarin () or 2''H''-chromen-2-one is an aromatic organic chemical compound with formula . Its molecule can be described as a benzene molecule with two adjacent hydrogen atoms replaced by an unsaturated lactone ring , forming a second six-me ...

, a natural product and precursor for the widely used Coumadin. Azidocoumarin has emerged as a widely applicable labeling agent in diverse biological systems. In particular, it participates in the aptly named '' click reaction'' with

alkynes \ce \ce Acetylene \ce \ce \ce Propyne \ce \ce \ce \ce 1-Butyne In organic chemistry, an alkyne is an unsaturated hydrocarbon containing at least one carbon—carbon triple bond. The simplest acyclic alkynes with only one triple bond and no ...

. Bioconjugation involves the labeling of certain cellular components and is applicable to fields such a

proteomics Proteomics is the large-scale study of proteins. Proteins are vital macromolecules of all living organisms, with many functions such as the formation of structural fibers of muscle tissue, enzymatic digestion of food, or synthesis and replicatio ...

and functional genomics with a detachable, fluorescent tag.

Synthesis

A common way to produce the 3-azidocoumarin is by condensation of

salicylaldehyde Salicylic aldehyde (2-hydroxybenzaldehyde) is an organic compound with the formula . Along with 3-hydroxybenzaldehyde and 4-hydroxybenzaldehyde, it is one of the three isomers of hydroxybenzaldehyde. This colorless oily liquid has a bitter almo ...

and ''N''-acetylglycine or nitroacetate. The intermediate is trapped with

sodium azide Sodium azide is an inorganic compound with the formula . This colorless salt is the gas-forming component in some car airbag systems. It is used for the preparation of other azide compounds. It is highly soluble in water and is acutely poisonou ...

to produce the 3-azidocoumarin. The isomeric 4-azidocoumarin (CAS# 42373-56-8) product can also be prepared from

4-hydroxycoumarin 4-Hydroxycoumarin is a coumarin derivative with a hydroxy group at the 4-position. Occurrence 4-Hydroxycoumarin is an important fungal metabolite from the precursor coumarin, and its production leads to further fermentative production of the n ...

via the 4-chloro derivative, which reacts with sodium azide.

Uses

This compound is used for bioconjugation. The target, which contains a terminal alkyne functional group, is treated with the

organic azide Organic may refer to: * Organic, of or relating to an organism, a living entity * Organic, of or relating to an anatomical organ (anatomy), organ Chemistry * Organic matter, matter that has come from a once-living organism, is capable of decay or ...

in the presence of a Cu(I)

catalyst Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...

. The resulting

1,2,3-triazole 1,2,3-Triazole is one of a pair of isomeric chemical compounds with molecular formula CHN, called triazoles, which have a five-membered ring of two carbon atoms and three nitrogen atoms. 1,2,3-Triazole is a basic aromatic heterocycle. Synthesis ...

is fluorescent. The coumarin backbone is chosen to be used as the profluorophore due to its small size, biocompatibility, and its ability to be easily manipulated synthetically. Illustrative of this is the labeling of biological compounds such as the protein

calmodulin Calmodulin (CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all Eukaryote, eukaryotic cells. It is an intracellular target of the Second messenger system, sec ...

. Neither the azidocoumarin nor the alkyne substrate fluoresce. Azidocoumarin is also inert in biological systems and insensitive to pH and solvent. A variety of azidocoumarin compounds have been evaluated.

References

{{DEFAULTSORT:Azidocoumarin, 3- Organoazides Coumarins Reagents for biochemistry