5-Hexynoic Acid TCI H0882

5-Hexynoic Acid, CAS number 53293-00-8, is a six-carbon carboxylic acid carrying a terminal alkyne group at the end of its chain. The combination of these two functional groups makes it one of the most frequently encountered non-heterocyclic building blocks in organic synthesis and bioconjugate chemistry laboratories. The carboxylic acid group provides an attachment point for amide or ester formation, while the terminal alkyne serves as a handle for click reactions. In a single simple molecule, researchers obtain a highly flexible bidirectional linker for assembling complex molecular architectures.

The main appeal of this compound lies in the orthogonality of its two functional groups. The terminal alkyne is relatively inert under ordinary amide-formation conditions, so researchers can first couple the carboxylic acid to a target amine using standard coupling reagents, leaving the alkyne fully intact for a copper-catalysed azide-alkyne cycloaddition in a subsequent step. The methylene chain between the two groups supplies sufficient spacer length to minimise steric interaction between the molecules being joined. This property is what makes the compound a standard choice for linker design, rather than a specialty reagent reserved for unusual routes.

In Indonesian laboratories, 5-Hexynoic Acid is routinely used in university and institutional research groups working on organic synthesis, medicinal chemistry, and bioconjugation. It appears in projects that require labelled probes, modified peptides, or functionalised polymer and surface materials, where a reliable two-ended linker shortens the synthetic route. Because it belongs to the widely used non-heterocyclic building block family, it is typically kept as a general-purpose stock item in synthesis laboratories rather than ordered for a single experiment.

• Copper-catalysed azide-alkyne cycloaddition (click chemistry): the terminal alkyne acts as a ready-made reaction handle, letting researchers join azide-bearing partners under mild conditions without additional derivatisation of the molecule.
• Bioconjugate linker construction: the carboxylic acid end couples to amines on peptides, proteins, or other biomolecules while the alkyne remains free for a later, fully orthogonal ligation step.
• Amide and ester formation in organic synthesis: standard coupling reagents activate the carboxylic acid group, allowing the compound to be attached to a wide range of nucleophilic partners in routine sequences.
• Spacer and linker design for complex molecules: the intervening methylene chain provides separation between the two joined fragments, reducing steric interference that would otherwise complicate the coupling outcome.
• General non-heterocyclic building block work: as a bifunctional starting material, it shortens multi-step routes in medicinal chemistry and materials projects that need both an acid and an alkyne functionality.

• Product code: H0882
• Chemical name: 5-Hexynoic Acid

Store 5-Hexynoic Acid in a tightly closed original container, kept in a cool, dry, well-ventilated chemical store away from direct sunlight and incompatible materials, and follow the specific storage temperature stated on the manufacturer's label and safety data sheet. As a carboxylic acid, it should be kept separated from strong bases and strong oxidising agents. Handle the material inside a fume hood using appropriate personal protective equipment, including safety goggles, chemical-resistant gloves, and a laboratory coat. Avoid inhalation of vapour and any contact with skin or eyes, keep containers closed when not in use, and consult the manufacturer's safety data sheet before first use and before disposal of any residues.

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