Triazenes
Organic compounds with a diazoamino group
From Wikipedia, the free encyclopedia
Triazenes are organic compounds that contain the functional group R1−N=N−NR2R3, where the R are each any of various types of substituent groups.[2] Some medications and dyes are triazenes.[3] Formally, the triazenes are related to the unstable chemical triazene, H2N−N=NH.
Production
Triazenes are prepared from the N-coupling reaction between diazonium salts and primary or secondary amines.[4] The coupling reactions are typically mild, using a base such as sodium acetate,[5] sodium carbonate,[5] or sodium bicarbonate.[4]
The diazonium reagents are themselves available starting from amines. For symmetrical triazenes derived from primary amines, partial diazotization gives a mixture of the original amine and its diazo derivative that then couple with each other. For example, 1,3-diphenyltriazene (PhN=N−NHPh) can be made from aniline in a one-pot reaction.[5][6] For asymmetrical triazenes, for example (phenyldiazenyl)pyrrolidine (PhN=N−NC4H8), the phenyldiazonium salt must be pre-made.
Analogues of Tröger's base containing a symmetric pair of asymmetric triazene side-chains have been obtained similarly.[7]
Reactions and applications
Polymeric triazenes are applied as conductive and absorbent materials.[8]
Triazenes are bidentate ligands, reacting to form either a four-membered ring or a dinuclear 8-membered ring.[9] They have been used in the synthesis of cinnoline, functionalized lactams, and coumarins.[10][11]
In the presence of protonating or alkylating agents, triazenes decompose into ammonium and diazonium salts.[11] For example, triazenes have been used as in situ diazonium in thiophenol synthesis:[5]
A strategy for the protection and deprotection of sensitive secondary amines is also based on this principle.[10]
Triazenes derived from primary amines engage in tautomerism:
(The tautomers are identical for symmetric triazenes.)
Oxidation generates the highly electrophilic azidium intermediate cation:[12]