- Effect of substituent on regioselectivity and reaction mechanism in aminolysis of 2,4-dinitrophenyl X-substituted benzenesulfonates
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(Chemical Equation Presented) We report on a kinetic study for the nucleophilic substitution reactions of 2,4-dinitrophenyl X-substituted benzensulfonates (X = 4-MeO, 1a, and X = 4-NO2, 1c) with a series of primary amines in 80 mol % H2O/20 mol % DMSO at 25.0 °C. The reactions proceed through S-O and C-O bond fission pathways competitively. The fraction of the S-O bond fission increases as the attaching amine becomes more basic and the substituent X changes from 4-MeO to 4-NO2, indicating that the regioselectivity is governed by the electronic nature of the substituent X as well as the basicity of amines. The S-O bond fission has been suggested to proceed through an addition intermediate with a change in the rate-determining step (RDS) at pK°a = 8.9 ± 0.1. The electronic nature of the substituent X influences kNS-O and k1 values, but not the k2/k-1 ratios and the pK°a value significantly. Stabilization of the ground state (GS) through resonance interaction between the electron-donating substituent and the electrophilic center has been suggested to be responsible for the decreased reactivity of 1a compared to 1c. The second-order rate constants for the C-O bond fission exhibit no correlation with the electronic nature of the substituent X. The distance effect and the nature of the reaction mechanism have been suggested to be responsible for the absence of the correlation.
- Um, Ik-Hwan,Hong, Jin-Young,Seok, Jin-Ah
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- Readily functionalizable phosphonium-tagged fluorescent coumarins for enhanced detection of conjugates by mass spectrometry
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Fluorescent coumarins are an important class of small-molecule organic fluorophores ubiquitous in different well-established and emerging fields of research including, among others, biochemistry and chemical biology. The present work aims at covering the poor detectability of coumarin-based conjugates by mass spectrometry while keeping important photophysical properties of the coumarin core. In this context, the synthesis of readily functionalizable phosphonium-tagged coumarin derivatives enabling a dual mass-tag and fluorescence labelling of analytes or (bio)molecules of interest through a single-step protocol, is reported. The utility of these coumarins is illustrated through the preparation of fluorogenic substrates that facilitated identification of the peptide fragment released by specific proteolytic cleavages.
- Lizzul-Jurse, Antoine,Bailly, Laetitia,Hubert-Roux, Marie,Afonso, Carlos,Renard, Pierre-Yves,Sabot, Cyrille
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- Properties of 2,4-dinitrophenyl derivatives of amino acids as analytical forms for high-performance liquid chromatography
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Dissociation constants of 2,4-dinitrophenyl derivatives of α-amino acids in micellar solutions of sodium dodecyl sulfate used as a micellar mobile phase in reversed-phase liquid chromatography were determined. The method of micellar liquid chromatography was used to determine the composition of polypeptide fractions of animal origin.
- Boichenko,Chernyshova,Kulikov,Loginova
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- A general approach for the development of fluorogenic probes suitable for no-wash imaging of kinases in live cells
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A general approach is presented for developing small molecule-based fluorogenic probes suitable for no-wash imaging of endogenous kinases in live cells. Probe 1, including a fluorophore-quencher system, was only turned on upon reacting with its target kinase Btk, and disclosed Btk's cellular location in live cells without any washing.
- Zhang, Qing,Liu, Hui,Pan, Zhengying
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- Efficient nucleophilic substitution reaction of aryl halides with amino acids under focused microwave irradiation
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The nucleophilic substitution reaction of 2,4-dinitrofluorobenzene with amino acids was complete, under microwave iradiation, within 40 s with yields up to 93%, which are far superior to those obtained under conventional heating. (C) 2000 Elsevier Science Ltd.
- Cherng, Yie-Jia
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- COVALENT IMMUNE RECRUITER COMPOUNDS FOR IMMUNE CELL RECOGNITION AND ASSOCIATED USES
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The present application relates to compounds of Formula I comprising an antibody binding domain (ABD) comprising a hapten that binds to an antibody in a subject, the antibody comprising a hapten binding site, an antibody labelling domain (ALD) comprising a functional group that forms a covalent bond with an amino acid in the antibody that is proximal to the hapten binding site and the formation of the covalent bond results in elimination of the ABD and either a target binding domain (TBD) or a detection moiety domain (DMD), each domain being optionally connected with independently selected linkers. The present application also includes methods and uses of the compounds, for example, for immune recognition of target cells by recruited labelled antibodies. [in-line-formulae]ABD?(L1)n-ALD-(L2)m-R[/in-line-formulae]
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Paragraph 0268; 0273; 0276-0277
(2021/09/10)
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- RETRACTED ARTICLE: Sanger's Reagent Sensitized Photocleavage of Amide Bond for Constructing Photocages and Regulation of Biological Functions
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Photolabile groups offer promising tools to study biological processes with high spatial and temporal control. In the investigation, we designed and prepared several new glycine amide derivatives of Sanger's reagent and demonstrated that they serve as a new class of photocages for Zn2+ and an acetylcholinesterase (AChE) inhibitor. We showed that the mechanism for photocleavage of these substances involves initial light-driven cyclization between the 2,4-dinitrophenyl and glycine methylene groups to form acyl benzimidazole N-oxides, which undergo secondary photoinduced decarboxylation in association with rupture of an amide bond. The cleavage reactions proceed with modest to high quantum yields. We demonstrated that these derivatives can be used in targeted intracellular delivery of Zn2+, fluorescent imaging by light-triggered Zn2+ release, and regulation of biological processes including the enzymatic activity of carbonic anhydrase (CA), negative regulation of N-methyl-d-aspartate receptors (NMDARs), and pulse rate of cardiomyocytes. The successful proof-of-concept examples described above open a new avenue for using Sanger's reagent-based glycine amides as photocages for the exploration of complex cellular functions and signaling pathways.
- Wei, Tingwen,Lu, Sheng,Sun, Jiahui,Xu, Zhijun,Yang, Xiao,Wang, Fang,Ma, Yang,Shi, Yun Stone,Chen, Xiaoqiang
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supporting information
p. 3806 - 3813
(2020/03/10)
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- Specific nucleophile-electrophile interactions in nucleophilic aromatic substitutions
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We herein report results obtained from an integrated experimental and theoretical study on aromatic nucleophilic substitution (SNAr) reactions of a series of amines towards 1-fluoro-2,4-dinitrobenzene in water. Specific nucleophile-electrophile interactions in the title reactions have been kinetically evaluated. The whole series undergoes SNAr reactions where the formation of the Meisenheimer complex is rate determining. Theoretical studies concerning specific interactions are discussed in detail. It is found that H-bonding effects along the intrinsic reaction coordinate profile promote the activation of both the electrophile and the nucleophile. Using these results, it is possible to establish a hierarchy of reactivity that is in agreement with the experimental data. Second order energy perturbation energy analysis highlights the strong interaction between the ortho-nitro group and the acidic hydrogen atom of the amine. The present study strongly suggests that any theoretical analysis must be performed at the activated transition state structure, because the static model developed around the reactant states hides most of the relevant specific interactions that characterize the aromatic substitution process.
- Ormazábal-Toledo, Rodrigo,Contreras, Renato,Tapia, Ricardo A.,Campodónico, Paola R.
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supporting information
p. 2302 - 2309
(2013/04/10)
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- Pyrrolylquinoxalinediones: A new class of AMPA receptor antagonists
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Pyrrolylquinoxalinediones were synthesized and their affinities for the AMPA receptor were determined. Most compounds showed moderate to good affinities. The acetic acid derivative 8b exhibited a K(i) value of 70 nM and was equipotent to NBQX 1. Structure activity relationships are discussed. Selected compounds were tested for their potency to inhibit AMPA induced lethal convulsions in mice. In this in vivo model the compounds showed improved potency compared with NBQX.
- Lubisch,Behl,Hofmann
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p. 2887 - 2892
(2007/10/03)
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- Structure of Amino Acids Isolated from Hydrolyzed HV-Toxin M, a Host-soecific Toxin-related Compound Produced by Helminthosporium victoriae
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The chemistry of several of the specific toxins isolated from a culture medium of the phytopathogenic fungus Helminthosporium victoriae, a causal agent of Victoria blight disease of oat, was studied.The structures of the amino acid components of the isolated HV-toxin M were identified, and the absolute configurations of the asymmetric α-carbons were elucidated as (S) (I - V, Fig. 1), (S) for C-3 of 3-OH-leucine (II), (R) for C-3 of 3-OH-lysine (V) and (Z) for 3-chlorodehydroalanine (VII).The structure of the other toxin simultaneously isolated, HV-toxin H, was found to be identical with victorin C.
- Kono, Yoshiki,Kinoshita, Takeshi,Takeuchi, Setsuo,Daly, J. M.
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p. 505 - 512
(2007/10/02)
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- Kinetic study and analytical application of the hexadecyltrimethylammonium bromide-catalyzed reaction of 1-fluoro-2,4-dinitrobenzene with amines
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Arylation of amines by reaction with 1-fluoro-2,4-dinitrobenzene is catalyzed by micelles of cetrimonium bromide. This catalysis has been exploited to reduce the analysis time in the spectrophotometric determination of amines as their dinitrophenyl derivatives. The kinetics of the catalysis were studied for the five amines: alanine, phenylalanine, aniline, 4-methylaniline, and 4-methoxyaniline. The dependence of rate constant on surfactant concentration can be quantitatively accounted for by Berezin's model, in which uptake of the amine and the 1-fluoro-2,4-dinitrobenzene by the micelle is described as a partitioning phenomenon for both species. An alternative model is developed in which one reactant partitions into the micellar phase and the other binds to the micelle with 1:1 stoichiometry; the two models are formally equivalent. Intrinsic catalytic rate constants and binding constants were evaluated. About one-third to one-half of the maximum observed micellar acceleration is attributed to a true micellar catalysis, the remainder being ascribed to an increase in local reactant concentrations in the micelle.
- Wong,Connors
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p. 146 - 150
(2007/10/02)
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