Factors affecting the rates of thermal decomposition of azidothiophenes

Synthesis and Leishmanicidal Activity of Molecular Hybrids 1,2,3-Triazole-Chalcones

“…Mp: 31.8-33.0 °C (lit. [13], 34 °C); 1 H NMR (60 MHz, CDCl3): δ 3.79 (s, 3H, OCH3), 6.92 (m, 4H, Ar); 13 C-NMR (15 MHz, CDCl3): δ 55.7, 115.4, 120.2, 132.6, 157.3.…”

Demethylation of the SMe 2 substituent in cationic metallacarboranes. Halide anion influence

“…Geometry optimization and transition state search were performed using PBE [15] and BPBE [16] exchange-correlation functionals, the scalar-relativistic Hamiltonian [17], atomic basis sets of generally contracted Gaussian functions [18], and a density-fitting technique [19] as implemented in a recent version of Priroda code [20]. The all-electron triple-z basis set L2 (close to cc-pVTZ) [21] augmented by two polarization functions was used.…”

Rates of thermolysis of azidobenzenes in solution: large stabilizations of transition states by charge transfer from electron-donor substituents

“…Azidobenzene and 4-methoxyazidobenzene were each synthesized by diazotizing the corresponding amine and adding the diazonium solution to sodium azide in a sodium acetate buffer, following our published method. 9 The crude azides were purified by chromatography over silica gel with dichloromethane or chloroform elution.…”

“…One can calculate from published rate constants that, at 80 ЊC, the relative rates for azidobenzene, 5 the azidopyrazole 1 6 and 2-azidothiophene 7 are 1, 3600 and 69 000, respectively. (There is unfortunately no common solvent for these rate measurements, which were made in decalin, p-xylene and p-chlorotoluene respectively, but data already published 8,9 indicate that solvent change would cause only about a two-fold alteration in the figures). Whereas simple azidobenzenes are believed to thermolyse to a singlet nitrene in the rate-determining step, 1,2 the very high reaction rates observed for the azidoheterocycles have suggested 3,4,7,10 that the ring-opening shown in Scheme 1 is concerted with nitrogen loss.…”