Use of N-chloro-N-methyl-p-toluenesulfonamide in N-chlorination reactions
摘要:
Second-order rate constants (k2) were determined for the addition of ten nitrogenous organic compounds (benzylamine, 2,2,2-trifluoethylamine chlorhidrate, methylamine chlorhidrate, glycine ethyl ester chlorhidrate, glycine, glycylglycine chlorhidrate, morpholine, pyperidine, pyperazine and dimethylamine) to the N-chloro-N-methyl-p-toluenesulfonamide (NCNMPT) in the formation reaction of N-chloramines in aqueous solution at 25 degrees C and ionic strength 0.5M. The series of nucleophiles considered is structurally very varied and covers five pKa units. The kinetic behaviour is similar for all compounds, being the elementary step the transfer of chlorine from the NCNMPT molecule to the nitrogen of the free amino group. These reactions were found first order in both reagents. The values of the rate constants indicate that the more basic amines produce N-chloramines more readily. Rate constants for the nucleophilic attack are shown to correlate with literature data for some of these nitrogenous organic compounds in their reaction with N-methyl-N-nitroso-p-toluenesulfonamide. Both reactions involve that the rate determining step is the attack of nitrogenous compounds upon electrophilic centre (Cl or else NO group). NCNMPT is a particularly interesting substrate, for which has not hitherto been published kinetic information, that allows us to assess the efficiency and the competitiveness of this reaction and compare it with other agents with a Cl+ atom. Copyright (c) 2013 John Wiley & Sons, Ltd.
Studies relating to the ferredoxins. Part 3. The synthesis of some cysteine–glycine peptides for iron–sulphur complexing studies
作者:Ambikaipakan Balasubramaniam、Roger J. Burt、George Christou、Brian Ridge、H. N. Rydon
DOI:10.1039/p19810000310
日期:——
Three peptides with the general structure Ac-Gly2.(Cys.Glym)n.Cys.Gly3.Cys.Gly2.NH2(1; m= 2 or 3; n= 0 or 1), four with the general structure Ac.Gly2.Cysn.Gly2.NH2(2; n= 1–4), and three with the general structure HS.CH2.CH2.CO.Gly2.(Cys.Gly2)n.NH.CH2.CH2.SH (3; n= 0–2) have been synthesised for iron-sulphurcomplexingstudies.
三种具有通用结构Ac-Gly 2(Cys.Gly m)n .Cys.Gly 3 .Cys.Gly 2 .NH 2(1; m = 2或3; n = 0或1)的肽,其中四个具有通用结构Ac.Gly 2 .Cys n .Gly 2 .NH 2(2; n = 1-4),三个具有通用结构HS.CH 2 .CH 2 .CO.Gly 2(Cys.Gly 2)n .NH.CH 2 .CH 2 .SH(3; n= 0–2)已被合成用于铁硫络合研究。
Photochemically Induced Electron Transfer (PET) Catalyzed Radical Cyclization: A Practical Method for Inducing Structural Changes in Peptides by Formation of Cyclic Amino Acid Derivatives
A new radical cyclization reaction of unsaturated amino acid derivatives is presented. The reaction is induced by photoelectron transfer (PET) catalysis and proceeds, in comparison to commonly applied methods, under mild, nonoxidizing, and nontoxic conditions in neutral medium. This type of radical cyclization reaction can be used in peptide chemistry for inducing structural changes in peptides.
Synthesis and structural characterization of amino acid and peptide derivatives featuring N-(p-bromobenzoyl) substituents as promising connection unit for bio-inspired hybrid compounds
作者:Frank Eißmann、Edwin Weber
DOI:10.1016/j.molstruc.2011.03.058
日期:2011.5
Abstract Using a sequence of activation, blocking and peptide coupling procedures, a series of ten amino acid and peptide derivatives 1–6 (a, b, respectively) featuring a p-bromobenzoyl substituent attached to the amino group of the parent compound has been synthesized. X-ray crystal structures of two corresponding amino acid (1a, 1b), two amino acid ester (3a, 3b) and three peptide ester derivatives
Synthesis of new lipophilic phosphine oxide derivatives of natural amino acids and their membrane transport properties toward carboxylic acids
作者:S. A. Koshkin、A. R. Garifzyanov、N. V. Davletshina、O. N. Kataeva、D. R. Islamov、R. A. Cherkasov
DOI:10.1134/s1070428015090031
日期:2015.9
One-pot procedures were developed for the synthesis of lipophilic N-(dialkylphosphorylmethyl) derivatives of natural amino acids with high yields from dioctyl- or didecylphosphine oxide, formaldehyde, and amino acid in the presence of amino acid hydrochloride. The reactions with some amino acids were also effective under catalysis by crownether. The structure of the isolated N-(dialkylphosphorylmethyl)
开发了一锅法,用于在氨基酸盐酸盐的存在下,从二辛基或二癸基氧化膦,甲醛和氨基酸以高收率合成天然氨基酸的亲脂性N-(二烷基磷酰基甲基)衍生物。与某些氨基酸的反应在冠醚的催化下也是有效的。分离的N-(二烷基磷酰基甲基)和N,N-双(二烷基磷酰基甲基)氨基酸的结构是根据1 H,13 C和31 P NMR和质谱确定的。(S)-N的结构通过X射线分析证实了-[[(二环己基磷酰基)甲基]-α-丙氨酸,并表征了其分子在晶体中的分子间缔合。研究了新型磷酸化氨基酸相对于多官能团羧酸的膜传输特性,并估算了影响酸性底物膜传输效率和选择性的因素。揭示了通过含有N,N-双[(二辛基磷酰基)甲基]-β-丙氨酸的液膜选择性提取戊二酸。
The α-Effect in S<sub>N</sub>Ar Reaction of Y-Substituted-Phenoxy-2,4-Dinitrobenzenes with Amines: Reaction Mechanism and Origin of the α-Effect
作者:Hyo-Jin Cho、Min-Young Kim、Ik-Hwan Um
DOI:10.5012/bkcs.2014.35.8.2448
日期:2014.8.20
The α-Effect in SNAr Reaction of Aryloxy-2,4-dinitrobenzenes Bull. Korean Chem. Soc. 2014, Vol. 35, No. 8 2449stituted-phenoxy-2,4-dinitrobenzenes (1a-1g) with hydra-zine and glycylglycine as an α-nucleophile and a referencenormal-nucleophile, respectively to obtained further infor-mation on the origin of the α-effect in the S