50635-35-3Relevant academic research and scientific papers
New free-radical halogenations of alkanes, catalysed by N-hydroxyphthalimide. Polar and enthalpic effects on the chemo- and regioselectivity
Minisci, Francesco,Porta, Ombretta,Recupero, Francesco,Gambarotti, Cristian,Paganelli, Roberto,Pedulli, Gian Franco,Fontana, Francesca
, p. 1607 - 1609 (2007/10/03)
Reactions of alkanes with different halogenating systems are compared in order to explore the reactivity of phthalimido-N-oxyl radical in hydrogen abstraction; the importance of polar effects is emphasised.
MECHANISMS OF FREE-RADICAL REACTIONS. XXIV. QUANTITATIVE DESCRIPTION OF THE POLAR EFFECTS OF SUBSTITUENTS ON THE KINETICS OF THE FREE-RADICAL CHLORINATION OF ALIPHATIC COMPOUNDS BY N-CHLOROPIPERIDINE
Dneprovskii, A. S.,Mil'tsov, S. A.,Arbuzov, P. V.
, p. 1826 - 1835 (2007/10/02)
The free-radical chlorination of 1-substituted alkanes with electron-withdrawing substituents by N-chloropiperidine in trifluoroacetic acid was studied by the method of competing reactions, and the relative rate constants were obtained for all positions of the substrates.The data on the position selectivity can be described satisfactorily by means of an electrostatic model of the polar effect of the substituent, calculated according to the Kirkwood-Westheimer equation.The obtained characteristics of the electrostatic effect can be successfully applied to calculation of the substrate selectivity and the intermolecular relative rate constants for all the positions, beginning with the third.The Taft equation is unsuitable for description of the effect of substituents on the reaction rate.
THE LONG-RANGE ACTION OF THE POLAR EFFECT OF SUBSTITUENTS ON THE ABSTRACTION OF HYDROGEN IN FREE-RADICAL CHLORINATION PROCESSES
Aver'yanov, V. A.,Ruban, S. G.,Klykova, M. B.,Golubev, V. E.
, p. 435 - 439 (2007/10/02)
The free-radical chlorination of 1-chloroalkanes between C3 and C6 at 263 deg K was studied under conditions with wide variation in the concentrations of the substrates in benzene.By analysis of the products from chlorination of the pure substrates it was shown that the deactivating effect of the polar substituent does not extend beyond the third carbon atom and is mainly determined by the inductive effect.In the transition to an aromatic solvent the deactivating effect on the substituent extends to the fourth carbon atom.The results are substantiated in terms of a contribution from dipole-dipole interaction between the substituent and the polar form of the transition state to the polar effect of the substituents.
MECHANISMS OF FREE-RADICAL REACTIONS. XIX. SELECTIVITY OF THE FREE-RADICAL CHLORINATION OF 1-CHLOROALKANES BY N-CHLOROPIPERIDINE
Dneprovskii, A. S.,Mil'tsov, S. A.
, p. 265 - 269 (2007/10/02)
The free-radical chlorination of 1-chloroalkanes ClH2l+1Cl (l = 4-7) by N-chloropiperidine was studied by the method of competing reactions, and the relative constants for all the positions of the investigated substrates were determined.The chlorination is a highly electrophilic process, and the effect of the substituents is transmitted through at least six C-C bonds.The results can be described satisfactorily by means of an electrostatic model of the polar effect of the substituents according to the Kirkwood-Westheimer equation.At the same time an attempt to describe the obtained data by means of the Taft equation led to unsatisfactory results.
