Triazene

About: Triazene is a research topic. Over the lifetime, 759 publications have been published within this topic receiving 8714 citations. The topic is also known as: Triazene cleavage & 1-triazene.

Triazene drug metabolites. Part 10. Metal-ion catalysed decomposition of monoalkyltriazenes in ethanol solutions

Abstract: The metal ions Fe2+, Zn2+ and Cu2+ bring about the rapid decomposition of 1-aryl-3-alkyltriazenes to the corresponding anilines. For Fe2+, a linear dependence of the pseudo-first-order rate constant, k0 on [Fe2+] was observed, while for Zn2+ and Cu2+ plots of k0versus[metal ion] were curved and indicative of complex formation. For Fe2+, second-order rate constants k2Fe2+ for substituted 1-aryl-3-methyltriazenes follow a Hammett relationship giving rise to a ρ value of –3.0. For Zn2+ and Cu2+, the data were analysed in terms of an equilibrium constant, KM2+, for the dissociation of a metal-ion-triazene complex and the first-order rate constant for the collapse of this complex to products, k2M2+. Hammett ρ values of 1.0 for both KZn2+ and KCu2+ are found, and the corresponding ρ values for k2Zn2+ and K2Cu2+ are –1.3 and –1.9. There is reasonable correlation between the Taft Es parameter for the alkyl group and KCu2+, giving a δ value of –1.6. The dependence of k2Cu2+ on the alkyl group is not simple: k2Cu2+ decreases in the order Pr > Et ≠ PhCH2ca. 4-MeOC6H4CH2 > CD3ca. Me. The reactions catalysed by Cu2+ are inhibited by added nucleophilies e.g. Br– and N-methylimidazole.A mechanism is proposed in which the triazene complexes to the metal ion via the N(1) nitrogen atom of the E–cis conformer, then undergoes a fast proton transfer to form a complex involving the unconjugated tautomer which subsequently decomposes via unimolecular scission of the N(2)–N(3) bond to form an alkyldiazonium ion and an aniline–metal complex. The observed products then arise from rapid solvolysis of the metal–aniline complex and the alkyl diazomum ion.

Triazene Derivatives of Cytisine

Abstract: Die Aryldiazoniumsalze (I) reagieren mit Cytisin (II) im alkalischen pH-Bereich zu den Triazenen (III ).

Formation of 1,3-diaryltriazene 1-oxides by oxidation of diazoamino-benzenes with peroxybenzoic acid: isomer ratios, kinetics, and mechanism

Abstract: The oxidation of diazoaminobenzenes with peroxybenzoic acid in ether gives diaryltriazene 1-oxides in good yield. An electron-releasing substituent on one of the benzene nuclei directs the oxygen to the nearest nitrogen atom. With diazoaminobenzenes carrying substituents of similar polarity on the two benzene nuclei the two possible isomers are formed in comparable amounts. The plot of logarithms of isomer ratios against the difference between Brown and Okamoto's σ+ values for the two substituents in a triazene is a straight line (ρ–1·3). Kinetic studies show that the bimolecular rate constants obey the Hammett law for the sum of the Hammett σ values for the substituents in both benzene rings (ρ–0·87). Analysis of the effect of substituents on the rate and the isomer ratio suggests a mechanism which involves the rate-determining formation of a metastable intermediate, in which the oxygen atom from peroxybenzoic acid is tentatively regarded as bonded to both nitrogen atoms 1 and 3, and which rapidly collapses to isomeric N-oxides in a ratio determined by the nature of the substituents.