Kinetic study of the chlorine transfer fromN-chlorosuccinimide to amino compounds

Abstract

A kinetic study of the reactions of N-chlorosuccinimide (NCS) with glycine (Gly), sarcosine (Sar), 2-methylalanine (2MA), proline (Pro) and pyrrolidine (Pyr) was carried out. The reactions were found to be first order with respect to both NCS and the amine or amino acid and order ؊ 1 in proton concentration. In order to calculate the experimental activation parameters, the effect of temperature on the reaction rates was studied. The ionic strength and buffer concentration were found to have no effect on the rate constant. A reaction mechanism involving Cl + transfer from NCS to the amine or amino acid to form an N-chloro compound is proposed. ©

Kinetic study of the formation of N‐chloro compounds using N‐chlorosuccinimide

“…The N-chloro compounds present a typical band at 250 nm. [9,[40][41][42] The wavelengths chosen were 240 and 250 nm for the N-chlorobenzylamine and the N-chloro-2,2,2-trifluoroethylamine, respectively.…”

“…The inverse process could also occur, but this process does not affect the calculation of the rate constants of formation of the N-chloro-2,2,2-trifluoroethylamine and of the N-chlorobenzylamine under these experimental conditions. [9,22] Free-energy relationships Despite the fact that NCS is a compound whose power of chlorination has been known for many years, in the literature, we have found very few kinetic studies of the chlorination of nitrogenous compounds possessing an amino group, either primary (R 1 NH 2 ) or secondary (R 1 R 2 NH). The values found along with the values obtained in the present work for both amines are included in Table 2.…”

“…Rate constants and structural parameters for the reaction of nitrogenous compounds with N-chlorosuccinimide Nitrogenous compound pK a k NCS /M À1 s À1 Σσ* [68,69] n N + Ref. [11] Glycine 9.68 6.3Â10 5 0.92 5.11 6.51 [9] Methylethanolamine 9.9 3.9Â10 6 0.69 5.38 7.40 [11] [10] 4.1Â10 7 0.49 5.83 7.95 [11] Diethylamine 11.02 4.6Â10 7 0.29 5.20 6.85 [11] Piperidine 11.12 4.3Â10 7 0.35 5.67 7.92 [10] Pyrrolidine 11.22 1.55Â10 7 0.23 5.02 8.11 [9] a Calculated by Hall's equations: pK a = 13.23 À 3.14 Σσ * and pK a = 12.13 -3.23 Σσ *, for primary and secondary amines, respectively. [70] b Calculated by the linear relation: N + = (-6 ± 1) + (2.5 ± 0.2)n. c Obtained in this work.…”

“…[1][2][3][4][5][6][7] Sodium hypochlorite, N-chlorosuccinimide (NCS), chloramine-T, chloramine-B, and tert-butyl hypochlorite are some of the most common reagents used to obtain N-chloro compounds. [8][9][10][11][12][13][14][15] All of them contain one electrophile chlorine atom, positive chlorine, able to react with amino acids, amines, amides, and other nitrogenous compounds to form the corresponding N-chloro compound. These reactions occur by the rupture of the N-H bond and formation of the N-Cl bond.…”

Modification of IκBα by taurine bromamine inhibits tumor necrosis factor α-induced NF-κB activation

“…In addition, it may be worth mentioning the following. The reactivity order as oxidizing agents of N-halide compounds is generally N-Br > N-Cl [46,47]. Therefore, once TauCl and TauBr enter a cell in equal amounts, it is conceivable that TauBr is more reactive than TauCl.…”