127-65-1Relevant articles and documents
Kinetic and Mechanistic Studies of Indigocarmine Oxidation by Chloramine-T and Chlorine in Acidic Buffer Media
Venkatesha, B. M.,Ananda, S.,Mahadevappa, D. S.,Gowda, N. M. Made
, p. 663 - 674 (1995)
Oxidations of indigocarmine (IC) by chloramine-T (CAT) and aqueous chlorine (HOCl) in acidic buffer media, pH 2-6, have been kinetically studied at 30 deg C using spectrophotometry.The CAT reaction rate shows a first-order dependence on 0 and an inverse fractional order on .The effect of on the rate is strongly pH dependent with a variable order of 1-2 on 0 in the pH range 6-2.The chlorine reaction rate follows first-order in 0 and 0 each in the pH range 6-2.Addition of halide ions and variation of ionic strength of the medium have no influence on the reaction rate.There is a negative effect of dielectric constant of the solvent.The kinetics of the IC oxidation with CAT at pH 6 and of that with HOCl at pHs 2-6 are similar suggesting similarity in their rate determining steps.A two-pathway mechanism for the CAT reaction and a one-pathway mechanism for the HOCl reaction, consistent with the kinetic data, have been proposed.Activation parameters have been calculated using the Arrhenius and Erying plots.
Controlled Relay Process to Access N-Centered Radicals for Catalyst-free Amidation of Aldehydes under Visible Light
Chang, Sukbok,Jeon, Hyun Ji,Jung, Hoimin,Kim, Dongwook,Lee, Wongyu,Seo, Sangwon
supporting information, p. 495 - 508 (2021/01/28)
Nitrogen-centered radicals have attracted increasing attention as a versatile reactive intermediate for diverse C–N bond constructions. Despite the significant advances achieved in this realm, the controllable formation of such species under catalyst-free conditions remains highly challenging. Here, we report a new relay process involving the slow in situ generation of a photoactive N-chloro species via C–N bond formation, which subsequently enables mild and selective access to N-centered radicals under visible light conditions. The utility of this approach is demonstrated by the conversion of aldehydes to amides, employing N-chloro-N-sodio carbamates as a practical amidating source. This synthetic operation obviates the need for catalysts, external oxidants, and coupling reagents that are typically required in related processes, consequently allowing high functional group tolerance and excellent applicability for late-stage functionalization. Amides are an important class of structural motifs prevalently found in bioactive compounds and synthetic materials of great significance. Amidation of aldehydes has been established as an atom-efficient strategy for amide synthesis; however, current methods lack in applicability mainly due to the requirement of troublesome reagents. In this article, we describe an unconventional relay process to convert aldehydes to amides under catalyst-, oxidant-, and coupling-reagent-free conditions, which is enabled by the development of a new mechanistic platform that gives efficient and controllable access to N-centered radicals under visible light. A wide range of (hetero)aromatic and aliphatic aldehydes can be employed, including those derived from biologically relevant complex molecules. We anticipate that the accomplished methodological advances, combined with the unique mechanistic features, will lead to the widespread application of the present strategy in broad research fields. A catalyst-free approach for controlled access to N-centered radicals is described, which enables the conversion of aldehydes to amides via an unconventional relay process harnessing visible light. The key tactic relies on the use of photostable N-chloro-N-sodio-carbamate amidating reagent that leads to slow incorporations of a photoactive radical source via C–N formation and other involved intermediates thereafter. This methodology displays excellent applicability and sustainable chemistry credentials and, thus, holds a promise for finding broad applications.
Preparation of several active N-chloro compounds from trichloroisocyanuric acid
Shiri, Azam,Khoramabadi-Zad, Ahmad
experimental part, p. 2797 - 2801 (2010/01/21)
A very simple method for the preparation of several activeN-chloro compounds that have extensive applications in organic synthesis, industry, and medicine has been developed.Tetrachloroglycolurils, chloramine-T, N-chlorosaccharin, N-chlorosuccinimide, N-chlorophthalimide, N,N￠-dichlorophenobarbital,and N,N￠-dichlorobarbital were synthesized by chlorination with trichloroisocyanuric acid under mild reaction conditions at roomtemperature. This method is clean, fast, and efficient; the yields are also good to excellent. Georg Thieme Verlag Stuttgart.
Kinetics and mechanism of oxidation of D-fructose and D-glucose by sodium salts of N-(chloro)-mono/di-substituted benzenesulfonamides in aqueous alkaline medium
Gowda, B. Thimme,Damodara,Jyothi
, p. 572 - 582 (2007/10/03)
In an effort to introduce N-chloroarylsulfonamides of different oxidizing strengths, nine sodium salts of mono- and di-substituted N- chloroarylsulfonamides are employed as oxidants for studying the kinetics of oxidation of D-fructose and D-glucose in aqueous alkaline medium. The results are analyzed along with those by the sodium salts of N-chlorobenzenesulfonamide and N-chloro-4-methylbenzenesulfonamide. The reactions show first-order kinetics each in [oxidant], [Fru/Glu], and [OH-]. The rates slightly increase with increase in ionic strength of the medium. Further, the rate of oxidation of fructose is higher by 4 to 5 times than that of the glucose oxidation, by the same oxidant. Similarly, Ea values for glucose oxidations are higher by about 1.5 times the Ea values for fructose oxidations. The results have been explained by a plausible mechanism, and the related rate law deduced. The significant changes in the kinetics and thermodynamic data are observed with change of substituent in the benzene ring. It is because Cl + is the effective oxidizing species in the reactions of N-chloroarylsulfonamides. The oxidative strengths of the latter therefore depend on the ease with which Cl+ is released from them. The ease with which Cl+ is released from N-chloroarylsulfonamides depends on the electron density of the nitrogen atom of the sulfonamide group, which in turn depends on the nature of the substituent in the benzene ring. The following Hammett equations are valid for the oxidation of fructose and glucose, log kobs = -3.13 + 0.54 σ ρ and log kobs = -3.81 + 0.28 σ ρ, respectively. The enthalpies and entropies of activations for oxidations by all the N-chloroarylsulfonamides correlate well with isokinetic temperatures of 301 K and 299 K, for fructose and glucose oxidations, respectively. The effect of substitution in the oxidants on the Ea and log A for the oxidations is also considered.
A Study of Substituent Effect on the Oxidative Strengths of N-Chloroarenesulphonamides: Kinetics of Oxidation of Leucine and Isoleucine in Aqueous Acid Medium
Shetty, Mahesha,Gowda, B. Thimme
, p. 63 - 72 (2007/10/03)
To study the variation of oxidative strengths of N-chloro- arenesulphonamides with substitution in the benzene ring, six mono- and five di-substituted N-chloro-arenesulphonamides are employed as oxidants for studying the kinetics of oxidation of two neutral amino acids, L-leucine and L-isoleucine in aqueous acid medium. The N-chloro-arenesulphonamides studied are of the constitution: ArSO2NaNCl·H2O (where Ar = C6H5, 4-CH3C6H4, 4-C2H5C6H4, 4-FC6H 4, 4-ClC6H4, 4-BrC6H4, 2,3-(CH3)2C6H3, 2,4-(CH 3)2C6H3, 2-CH3-4-Cl 2C6H3, 2,4-Cl2C6H 3, and 3,4-Cl2C6H3). The reactions show second order kinetics in [oxidant], fractional order in [amino acid] and inverse dependence on [H+]. Addition of the reduced product of the oxidants or variation in ionic strength of the medium has no significant effect on the rates of oxidations. A two-pathway mechanism is considered to explain the experimental results. Effective oxidizing species of the oxidants is Cl + in different forms. Therefore the oxidising strengths of N-chloro-arenesulphonamides depend on the ease with which Cl+ is released from them. The study reveals that the introduction of substituent in the benzene ring of the oxidant affects both the kinetic and thermodynamic data for the oxidations The electron releasing groups such as CH3 generally inhibit the rates, while electron-withdrawing groups such as Cl enhance this ability, as the electron withdrawing groups ease the release of Cl+ from the reagents and hence increase the oxidising strengths. The on Ea and log A and validity of the Hammett and isokinetic relationships for the oxidations are also analysed.
Process for the production of radioiodinated neuroreceptor agents
-
, (2008/06/13)
The present invention is related to process for producing radioiodinate neuroreceptor agents with improves yields. In said process the trialkyltin group of the precursor of the neuroreceptor agent is replaced by radioiodine in the presence of an oxidation agent, preferably chloramine T in a pH adjusted by a buffering system comprising inorganic or organic acids and their salts. The end-products are subsequently separated from the by-products using chromatographic separation methods such as high performance liquid chromatography (HPLC), wherein the mobile solvent phase comprises a mixture of ethanol and water having a pH of 1-6. The improved yield are obtainable by preventing the formation of volatile radioactive by-products and by using a non-toxic solvent system in the chromatographic separation process, which simplifies the down stream processing of the end product.
