84713-95-1Relevant academic research and scientific papers
Triaziridines. Ring Openings of Triaziridines
Hipert, Hans,Dreiding, Andre S.
, p. 277 - 291 (2007/10/02)
Eleven triaziridine derivatives were heated at 60 deg C in CDCl3 to obtain information on the tendency towards, resp. the resistance to, ring opening of the N3-homocycle by thermolysis.Among these triaziridines, there are three which contain, as one of the substituents, a methoxycarbonyl group (ester derivatives 1, 5, and 16), three a methyl group (methyl derivatives 18, 24, and 26), three an H-atom (14, 27, and 30), and two a negative charge (31 and 32).The other two substituents in each of these four classes of triaziridines are trans-located i-Pr groups (1, 18, 27, and 31), cis-located i-Pr groups (5, 24, 14, and 32), and a 1,3-cis-cyclopentylidene group (16, 26, and 30).As major products of these mild thermolyses, we isolated: from the trans-ester 1 and from the annellated ester derivative 16, the 1-acyl-azimines 2 and 17, respectively, from the cis-ester 5, the 3-acyl-triazene 4, from the trans-methyl derivative 18, the (E)-diazene 19 and hexamine 21, from the cis-methyl derivative 24 the 2-methylazimine 25, both from the trans- and cis-H-derivatives 27 and 14, respectively, the H-triazene 13 and, finally, both from the trans- and cis-anion 31 and 32, respectively - after protonation - the H-triazene 13 and - after methylation - the methyl-triazene 33.The same thermolysis of the annelated methyl and H-derivatives 26 and 30, respectively, resulted only in decomposition.These results can be uniformly interpreted with a primary opening of the triaziridine ring by rupture of one of the two types of N-N bonds leading to azimines or triazenide anions.Some of the azimines were isolable, namely 2, 17, and 25, and one was spectroscopically observable as an intermediate, namely 11 on the way to the triazene 4.The other azimines are plausible intermediates to the isolated products, namely 15 on the way to 13, and 22 on the way to 19 and 21.The triazenide anion 28 is the evident intermediate on the way to 13 or to 33.The annelated azimines are assumed not be formed from 26 and 30, or then to be decomposed under the conditions of their formation.We conclude that the triaziridine derivatives 1, 16, and 18 underwent thermal ring opening between N(1) and N(2), while the derivatives 5, 14, 24, 27, 31, and 32 were ruptured between N(2) and N(3); no conclusion was possible on the ring opening of the derivatives 26 and 30.The predominant formation of the (Z)-azimine 2 from the trans-triaziridine 1, and of the (E)-isomer 3 - among the two azimines - from the cis-triaziridine 5 suggests a stereospecificity in the triaziridine ring openings.This would, however, not be expected to be observable in the products from the other triaziridines, since both N-N bonds of the azimine 25 and of the anion 28 probably rotate rapidly and since the secondary transformations of the other primary products are not able to retain configurational information.
Decomposition of 1,3-Dialkyltriazenes in Aqueous Buffers: Kinetic and Mechanistic Studies
Smith, Richard H.,Denlinger, Cheryl L.,Kupper, Robert,Mehl, Andrew F.,Michejda, Christopher J.
, p. 3726 - 3730 (2007/10/02)
1,3-Dialkyltriazenes, prepared by the reaction of alkyl azides with alkyllithiums, are stable as pure liquids or in aprotic solutions.The kinetics of decomposition of 1,3-dimethyltriazene (DMT) were investigated in buffered, aqueous solutions over the pH range of 9-12.The reaction is acid-catalyzed since the rate is inversely proportional to pH.The invariance of the rate with (cyclohexylamino)propanesulfonic acid (CAPS) buffer concentration at pH 9.5 and the finding of an inverse solvent isotope effect of 0.35 suggest that the reaction follows simple specific acid catalysis in that buffer.Decomposition of DMT in phosphate and carbonate buffers, however, indicated dependence of rate on buffer concentration, although the solvent isotope effects were still less than 1.These data suggested that the reaction in those buffers is catalyzed by specific acid, followed by general base.The kinetics of decomposition of 1,3-diethyltriazene (DET) and 1,3-diisopropyltriazene (DIT) were also studied.DET decomposed slightly more rapidly than DMT in phosphate and carbonate buffers but showed a similar dependence of the rate on the buffer concentration.This triazene also exhibited an inverse solvent isotope effect.DIT, on the other hand, showed a rate that was invariant with phosphate buffer concentration and exhibited a biphasic profile of rate vs. carbonate buffer concentration.The rate of decomposition of DIT was also invariant with the pKa of various buffers and showed an inverse solvent isotope effect.Decomposition of DMT in buffered deuterium oxide resulted in incorporation of deuterium into the product methanol, which indicated that an intermediate product of the reaction was the methyldiazonium ion.The dependence of the rate of decomposition on buffer concentration of DMT and DET is explained in terms of nucleophilic attack of buffer anions on N-2 of the protonated triazenes.The proponated DIT, on the other hand, is seen as dissociating directly to the isopropyl carbonium ion in phosphate buffer and in low concentrations of carbonate buffer.
1,3-Dialkyltriazenyl Radicals: Their Electron Spin Resonance Spectra, Electronic Configuration, and Addition to Trialkyl Phosphites
Brand, John C.,Roberts, Brian P.
, p. 1549 - 1558 (2007/10/02)
The 1,3-dialkyltriazenyl radicals , in which R = CH3, CD3, Pri, or But, have been generated in solution from the parent triazenes and studied by e.s.r. spectroscopy.The trazenyl radicals exhibit large hyperfine splitting from the central nitrogen, smaller splitting from two equivalent alkylated nitrogens, and characteristically low g factors of ca. 2.0020.These spectroscopic parameters are as expected for a ?-radical, in which the SOMO is in the NNN plane, and this electronic configuration is supported by the results of semiempirical molecular orbital calculations.Dialkyltriazenyl radicals add to trialkyl phosphites to give the cyclic triazyl radicals (A), which may be regarded as 'spin-labelled' phosphoranes.The same radicals are produced by cyclisation of dialkyltriazeno(trialkoxy)phosphoranyl radicals (R2O)3PN(R1)N=NR1.The e.s.r. spectra of the spin-labelled phosphoranes exhibit temperature-dependent lineshape effects which are attributed to exchange of apical and equatorial nitrogen ligands, and an activation energy of 22 kJ mol-1 for this exchange was obtained by computer simulation of the spectra for (A; R1 = But, R2 = Me).
