2666-74-2Relevant academic research and scientific papers
Lifetimes of imidinium ions in aqueous solution
Dalby, Kevin N.,Jencks, William P.
, p. 7271 - 7280 (2007/10/03)
Imidinium ions, ArN=CNR2+, were generated in aqueous solution from the solvolysis of fluoro and chloro formamidines at pH 9.3 and 25°C. Rate constants for the hydration of five imidinium ions were determined from a kinetic analysis of their trapping by thiolacetate anion, CH3COS-, in the presence of a pool of competing fluoride anion, and a rate constant of k(AcS)- = 5 x 109 M-1 S-1 for diffusion-controlled trapping of the carbocations with thiolacetate anion. The rate constants, k(s), for hydration of the imidinium ions, XArN=CNC4H8O+ are 3.6 x 105, 5.8 x 105, 1.5 x 106, 1.6 x 106, and 1.8 x 106 s-1 for X = H, 4-Cl, 3-CN, 4-CN, and 3-NO2, respectively. In a similar experiment a rate constant of k(s) = 3.3 x 107 s-1 was obtained for hydration of the imidinium ion 4-NO2-ArN=CNCH3(OCH3)+, by using azide anion to trap the cation and a rate constant of k(az) = 5 x 109 M-1 s-1 for diffusion-controlled trapping of the imidinium ion with azide ion. The partitioning rate constant ratio k(AcS)-/k(s) for 4-ClArN=CNC4H8O+ decreases by approximately 6-fold in 45% v/v glycerol/water in contrast to k(az)/k(s), which remains almost constant, showing that thiolacetate, but not azide anion, combines with the imidinium ion at a diffusion-limited rate. The reactivity of the imidinium ions deviate from behavior predicted by the N+ scale in a manner that may be explained by a difference in the selectivity of the cation when compared to the more stable N+ carbocations.
Improved preparation of 5-chloro-1-phenyl-1H-tetrazole and other 5- chlorotetrazoles
Alves, Jose A.C.,Johnstone, Robert A.W.
, p. 2645 - 2650 (2007/10/03)
Reaction of aryldichloroisocyanides 1a-e with sodium azide and a phase transfer agent has provided 5-chloro-1-aryl-1H-tetrazoles 2a-e in good yield. In particular, the widely-used intermediate, 5-chloro-1-phenyl-1H-tetrazole 2a, can be produced conveniently and safely in yields approaching 100%.
POLYFLUOROARYLCARBONIMIDOYL DICHLORIDES AND CHLORIDES. A NEW METHOD OF OBTAINING SUCH COMPOUNDS FROM POLYFLUOROAROMATIC AMINES AND COMPOUNDS OF THE CCl3R TYPE IN THE PRESENCE OF AlCl3
Savchenko, T. I.,Kolesnikova, I. V.,Petrova, T. D.,Platonov, V. E.
, p. 439 - 458 (2007/10/02)
Reactions of some polyfluorinated amines of the benzene, diphenyl, naphtalene and pyridine series with CCl4 in the presence of AlCl3 have been investigated.A new method is proposed for producing polyfluoroarylcarbonimidoyl dichlorides ArfN=CCl2.The reaction is shown to be sufficiently general and applicable in the series of polychlorinated anilines and low-base anilines of the hydrocarbon series as well.The possibility of involving other compounds of the type CCl3R and other Lewis acids in the reaction has been studied.The factors influencing the course of the reaction and the mechanism of formation of polyfluoroarylcarbonimidoyl dichlorides are discussed.
