The Azide-Alkyne Huisgen Cycloaddition is a 1,3-dipolar cycloaddition between an azide and a terminal or internal alkyne to give a 1,2,3-triazole. Huisgen ^[1] was the first to understand the scope of this organic reaction. This cycloaddition is considered the cream of the crop of click chemistry. The 1,3-dipolar cycloaddition is an organic chemical reaction (specifically, a cycloaddition) between a 1,3-dipole and a dipolarophile mostly a substituted alkene to form a substituted five-membered ring. ... An azide is the N3- anion, the anion of hydrazoic acid or a reactive group in organic chemistry where a carbon substituent is attached as RN3. ... Alkynes are hydrocarbons that have at least one triple bond between two carbon atoms. ... 1,2,3-Triazole is one of a pair of isomeric chemical compounds with molecular formula C2H3N3, called triazoles, which have a five-membered ring of two carbon atoms and three nitrogen atoms. ... Organic reactions are chemical reactions between organic compounds. ... A Cycloaddition is a pericyclic reaction in which the net result is loss of two pi bonds and gain of two sigma bonds. ... Click chemistry is a concept introduced by K. Barry Sharpless in 2001 and describes chemistry tailored to generate substances quickly and reliably by joining small units together as nature does. ...

In the reaction above ^[2] azide 2 reacts neatly with alkyne 1 to afford the triazole 3 as a mixture of 1,4-adduct and 1,5-adduct at 98 °C in 18 hours. Image File history File links Huisgen cycloaddition File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... The degree Celsius (°C) is a unit of temperature named after the Swedish astronomer Anders Celsius (1701–1744), who first proposed a similar system in 1742. ...

Variants of the Huisgen reaction

A notable variant of the Huisgen 1,3-dipolar cycloaddition is the copper(I) catalyzed variant, in which organic azides and terminal alkynes are united to afford 1,4-regioisomers of 1,2,3-triazoles as sole products. The copper(I)-catalyzed variant was first reported by Morten Meldal and co-workers at the Carlsberg Laboratory in Denmark. While the copper(I) catalyzed variant gives rise to a triazole from a terminal alkyne and an azide, formally it is not a 1,3-dipolar cycloaddition and thus should not be termed a Huisgen cycloaddition. This reaction is better termed the Copper(I)-catalyzed Azide-Alkyne Cycloaddition (CuAAC). But it is certainly a click reaction. While the reaction can be performed using commerical sources of copper(I) such as cuprous bromide or iodide, the reaction works much better using a mixture of copper(II) (e.g. copper(II) sulfate) and a reducing agent (e.g. sodium ascorbate) to produce Cu(I) in situ. As Cu(I) is unstable in aqueous solvents, stabilizing ligands are effective for improving the reaction outcome, especially if Tim's Ligand (TBTA) is used. Those organic chemists serious about success in running these reactions will prepare their own TBTA ligand. The reaction can be run in a variety of solvents, and mixtures of water and a variety of (partially) miscible organic solvents including alcohols, DMSO, DMF, tBuOH and acetone work well. Owing to the powerful coordinating ability of nitriles towards Cu(I) it is best to avoid acetonitrile as the solvent. Tims ligand, or TBTA (tris-benzyl-triazolyl-amine) is a ligand which when attached to Copper (I) allows for quantitative, regioselective Huisgen 1,3-dipolar cycloadditions between alkynes and azides, in aqueous solutions. ...

NH-1,2,3-triazoles are also prepared from alkynes in a sequence called the Banert cascade. The Banert cascade is an organic reaction in which a NH-1,2,3-triazole is prepared from a propargyl halide or sulphate and sodium azide in a dioxane- water mixture at elevated temperatures. ...

The utility of the Cu(I) catalyzed click reaction has also been demonstrated in the polymerization reaction of a bis-azide and a bis-alkyne with copper(I) and Tim's Ligand (TBTA) to a conjugated fluorene based polymer ^[3]. The degree of polymerization easily exceeds 50 and with a stopper molecule such as phenyl azide well defined phenyl end-groups are obtained. This is the article about the process. ... Tims ligand, or TBTA (tris-benzyl-triazolyl-amine) is a ligand which when attached to Copper (I) allows for quantitative, regioselective Huisgen 1,3-dipolar cycloadditions between alkynes and azides, in aqueous solutions. ... A chemically conjugated system, is a system of atoms covalently bonded with alternating single and double bonds (e. ... Fluorene Fluorene, or 9H-fluorene, is a polycyclic aromatic hydrocarbon. ... A polymer is a substance composed of molecules with large molecular mass consisting of repeating structural units, or monomers, connected by covalent chemical bonds. ... The degree of polymerization, or DP, is the number of repeat units in an average polymer chain at time t in a polymerization reaction. ... Phenylazide is an organic compound with the formula C6H5N3. ... In chemistry, the phenyl group or phenyl ring (often abbreviated as -Ph) is the functional group with the formula -C6H5 Picture where the six carbon atoms are arranged in a cyclic manner. ... An end-group in polymer chemistry is a constitutional unit that is an extremity of a macromolecule or oligomer molecule. ...

The CuAAC click reaction also effectively couples polystyrene and bovine serum albumin (BSA) ^[4]. The result is an amphiphilic biohybrid. BSA contains a thiol group at Cys-34 which is functionalized with an alkyne group. Polystyrene has an azido end-group and the coupling takes place in a THF / phosphate buffer solution with Copper(II) sulfate and ascorbic acid. In water the biohybrid micelles with a diameter of 30 to 70 nanometer form aggregates. Image File history File links Clickpolymer. ... Polystyrene is a polymer made from the monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum by the chemical industry. ... Bovine serum albumin, Bovine Albumin, BSA: A serum albumin protein that can be used as a diluent or a blocking agent in numerous applications including ELISAs (Enzyme-Linked Immunosorbent Assay), blots and immunohistochemistry. ... An amphipathic (a. ... Sulfhydryl // In organic chemistry, a thiol is a compound that contains the functional group composed of a sulfur atom and a hydrogen atom (-SH). ... Cysteine is a naturally occurring amino acid which has a thiol group and is found in most proteins, though only in small quantities. ... Alkynes are hydrocarbons that have at least one triple bond between two carbon atoms. ... An azide is a N3- anion, or a reactive group in organic chemistry where a carbon substituent is attached as RN3. ... An end-group in polymer chemistry is a constitutional unit that is an extremity of a macromolecule or oligomer molecule. ... Tetrahydrofuran, also known as THF, hydrofuran, oxolane, oxacyclopentane, or furanidine, is a heterocyclic organic compound. ... Above is a ball-and-stick model of the inorganic hydrogenphosphate anion (HPO42−). Colour coding: P (orange); O (red); H (white). ... Acids and bases: Acid-base reaction theories pH Self-ionization of water Buffer solutions Systematic naming Electrochemistry Acid-base extraction Acids: Strong acids Weak acids Superacids Lewis acids Mineral acids Organic acids Bases: Strong bases Weak bases Superbases Lewis bases Organic bases edit Buffer solutions are solutions which resist change... Copper(II) sulfate, the chemical compound with the formula CuSO4, is a common salt of copper. ... This article deals with the molecular aspects of ascorbic acid. ... Schematic of a micelle. ... DIAMETER is an AAA protocol (Authentication, Authorization and Accounting) succeeding its predecessor RADIUS. // The name is a pun on the RADIUS protocol, which is the predecessor (a diameter is twice the radius). ... A nanometre (American spelling: nanometer) is 1. ...

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