Triazenes
Triazenes or also diazoamines are chemical compounds with the general structure R 1 R 2 N-N = N R 3 , the name also being used for the corresponding functional group . They should not be confused with the triazines . Triazenes consist of an amino group which is directly linked to an azo group and is therefore also referred to as a diazoamino group (= triazene group). ( Diazo compounds are compounds in which two nitrogen atoms are directly connected to one another.) They can be produced, for example, by azo coupling of anilines . Triazenes can tautomerize.
Triazene formation
Triazene formation is a mostly undesirable side reaction in the azo coupling to aromatic amines ( coupling component ). The diazo component is produced by reacting an aromatic amine with nitrous acid (diazotization).
The diazonium cation then reacts with the most nucleophilic site of the so-called coupling component, the amine nitrogen, instead of the electrophilic substitution of an aryl hydrogen.
Triazene disintegration
The triazene formation is reversible. In a strongly acidic environment, they break down again into their starting components when heated, or after tautomerization into other compounds capable of coupling (the former diazo component is reformed as an amine, the former coupling component now carries the diazo group).
Triazene rearrangement
The starting compounds can "rearrange" to the desired azo compound. If the triazene breaks down in such a way that the former diazocation and the coupling component are regressed, the desired product is obtained in the subsequent azo coupling. However, the triazene can (after tautomerization) also decompose in such a way that the former diazo and the diazotized coupling component are formed, so the diazo group is located in the “wrong” molecule. Their by-products are undesirable and in the best case only reduce the yield.
links
The simplest compound of this group of substances with the formula NH 2 N = NH is named as the name giver triazene . Another known compound of group is the di phenyl derivative of the triazene, the Diphenyltriazen also diazoaminobenzene called (Ph-NH-N = N-Ph). In the compounds, R 1 is often aryl groups and R 3 is often alkyl , allyl or benzyl compounds . By heating in an acidic solution, triazene compounds can be converted into the thermodynamically more stable aminoazo compounds R 1 R 2 N = NR 3 -NH 2 .
use
Triazenes are used to produce other organic compounds (e.g. resins and drugs such as dacarbazine , diminazen, etc.).
See also
Web links
- Entry to triazenes . In: IUPAC Compendium of Chemical Terminology (the “Gold Book”) . doi : 10.1351 / goldbook.T06498 Version: 2.3.1.
- University of Karlsruhe: Solid phase synthesis with triazenes
Individual evidence
- ↑ Hartman, WW; Dickey, JB: Diazoaminobenzene In: Organic Syntheses . 14, 1934, p. 24, doi : 10.15227 / orgsyn.014.0024 ; Coll. Vol. 2, 1943, p. 163 ( PDF ).
- ^ Chemgapedia: Azo coupling