Showing papers on "Triazene published in 1975"
TL;DR: In this paper, the first synthesis of 4-methyl-2-t-butyl-and 2 methyl-4,6-di-t -butylindole is described.
Abstract: The first syntheses of 4-methyl-2-t-butyl- and 2 methyl-4,6-di-t-butyl-indole are described. Rates of diazo-coupling at the 3-position of both these compounds together with those for 2-methyl- and 2-t-butyl-indole are reported for various para-substituted arenediazonium ions in mixed aqueous and some aprotic solvents at 25°. The kinetic behaviour of 2-methylindole is examined in detail and it is shown that 3-coupling may proceed through either the neutral compound or the 2-methylindolyl anion depending on the pH, with the anion being ca. 108-fold more reactive. For neutral 2-methylindole coupling, rates increase with increasing reactivity of the diazonium ion giving p 3.3 for the Hammett (ρσ+) plot, and for coupling with p-toluenediazonium ion ΔH‡= 38 kJ mol–1 and ΔS‡= 138 J K–1 mol–1. Kinetic isotope effects for coupling to [3-2H1]- and [3-3H1]-2-methylindole and 3-deuteriated 2-t-butyl-and 4-methyl-2-t-butyl-indole are not apparent in aqueous dioxan. Coupling to 2-methyl-4,6-di-t-butylindole is also shown to proceed via both the neutral substrate and its conjugate base, but these reactions show significant primary hydrogne isotope effects (KH/KDca. 7). The results are interpreted in terms of a classical A–SE2 mechanism for both neutral indoles and indolyl anions in which direct electrophilic attack by the arene diazonium ion at the 3-position is normally rate limiting. The change in the rate limiting step observed for the A–SE2 mechanism with 2-methyl-4,6-di-t-butylindole is attributed to steric hindrance acting only on proton explusion in a very reactant-like transition state and not on attack of the electrophilic diazonium ion. There is no evidence for coupling to indole nitrogen and triazene intermediates are therefore not significant in any of these reactions.
23 citations
TL;DR: None of the triazenylimidazole-4-carbonitriles were active against lymphatic leukemia L-1210 im mice, and like the analogous carboxamide, the bis(2-chloroethyl) triazene readily cyclizes to the 1, 2, 3-triazolinium chloride.
6 citations
TL;DR: In this article, 3,3-(14C)-Dimethyl-1-phenyltriazene was prepared from recrystallized benzenediazonium fluoroborate which was coupled with 14C-dimethylamine in excess aqueous sodium carbonate at 0°.
Abstract: 3,3-(14C)-Dimethyl-1-phenyltriazene was prepared from recrystallized benzenediazonium fluoroborate which was coupled with 14C-dimethylamine in excess aqueous sodium carbonate at 0°. The crude product was extracted with ether and purified by distillation. Redistilled 14C-labelled triazene was obtained in good yield (70.4 and 73.5%) and in high radiochemical purity (better than 99.9% by scan of thin-layer chromatograms). The specific activities of two preparations, determined by liquid scintillation counting and corrected for quenching, were 244 and 296 μCi/mmole. The determined activities were in close agreement with values computed from the specific activity of 14C-dimethylamine hydrochloride used in the synthesis.
5 citations
Patent•
13 Feb 1975
TL;DR: Triazene derivatives of the formula "STR1" have been used as photographic toners and additives to photographic developers and as antimycotic agents in animal therapy as discussed by the authors.
Abstract: Triazene derivatives of the formula ##STR1## wherein X is = CH-- or nitrogen, Y is --CH = or nitrogen, R and R' are substituted or unsubstituted alkyl, aryl, arakyl or cycloarkyl. The compounds are effective as photographic toners and additives to photographic developers and as antimycotic agents in animal therapy.