Tag: M.W:100-200

COA of Formula: C4H5BrO4. The protonation of heteroatoms in aromatic heterocycles can be divided into two categories: lone pairs of electrons are in the aromatic ring conjugated system; and lone pairs of electrons do not participate. Compound: (S)-2-Bromosuccinic acid, is researched, Molecular C4H5BrO4, CAS is 20859-23-8, about Modification of three active site lysine residues in the catalytic subunit of aspartate transcarbamylase by D- and L-bromosuccinate. Author is Lauritzen, Ann M.; Lipscomb, William N..

Treatment of the catalytic subunit of aspartate transcarbamylase from Escherichia coli with either D- or L-bromosuccinate at pH 8.5 resulted in a loss of catalytic activity. Succinate, an analog of the substrate, L-aspartate, afforded some protection against inactivation, whereas the putative transition state analog, N-(phosphonacetyl)-L-aspartate provided complete protection. The substrate, carbamyl phosphate, provided greater protection against inactivation by L-bromosuccinate than by D-bromosuccinate. Complete loss of activity was accompanied by incorporation of ∼1.3 succinate moieties per catalytic chain resulting from partial modification of 3 lysine residues, identified as numbers 83, 84, and 224 in the preliminary catalytic chain sequence. A significant number of catalytic chains were modified at both positions 83 and 84. In the absence of ligands, D-bromosuccinate reacted with lysine-83 to a greater extent than did the L-isomer. Bulky inhibitors, e.g. CTP and pyridoxal phosphate, provided varying degrees of protection against inactivation and overall modification without altering significantly the relative extent of alkylation of the 3 residues. However, carbamyl phosphate not only protected against inactivation and overall modification, but also selectively suppressed alkylation of lysine-83 and eliminated the production of catalytic chains modified at both lysine-83 and -84. Apparently, all 3 lysine residues are at or near the active site, modification of any one of them causes loss of catalytic activity, and lysine-83 is at or near the carbamyl phosphate-binding site.

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Reference:
Copper catalysis in organic synthesis – NCBI,
Special Issue “Fundamentals and Applications of Copper-Based Catalysts”

Application of 492-27-3. The fused heterocycle is formed by combining a benzene ring with a single heterocycle, or two or more single heterocycles. Compound: 4-Hydroxyquinoline-2-carboxylic Acid, is researched, Molecular C10H7NO3, CAS is 492-27-3, about Prenatal Kynurenine Elevation Elicits Sex-Dependent Changes in Sleep and Arousal During Adulthood: Implications for Psychotic Disorders.. Author is Rentschler, Katherine M; Baratta, Annalisa M; Ditty, Audrey L; Wagner, Nathan T J; Wright, Courtney J; Milosavljevic, Snezana; Mong, Jessica A; Pocivavsek, Ana.

Dysregulation of the kynurenine pathway (KP) of tryptophan catabolism has been implicated in psychotic disorders, including schizophrenia and bipolar disorder. Kynurenic acid (KYNA) is a KP metabolite synthesized by kynurenine aminotransferases (KATs) from its biological precursor kynurenine and acts as an endogenous antagonist of N-methyl-D-aspartate and α7-nicotinic acetylcholine receptors. Elevated KYNA levels found in postmortem brain tissue and cerebrospinal fluid of patients are hypothesized to play a key role in the etiology of cognitive symptoms observed in psychotic disorders. Sleep plays an important role in memory consolidation, and sleep disturbances are common among patients. Yet, little is known about the effect of altered KP metabolism on sleep-wake behavior. We presently utilized a well-established experimental paradigm of embryonic kynurenine (EKyn) exposure wherein pregnant dams are fed a diet laced with kynurenine the last week of gestation and hypothesized disrupted sleep-wake behavior in adult offspring. We examined sleep behavior in adult male and female offspring using electroencephalogram and electromyogram telemetry and determined sex differences in sleep and arousal in EKyn offspring. EKyn males displayed reduced rapid eye movement sleep, while female EKyn offspring were hyperaroused compared to controls. We determined that EKyn males maintain elevated brain KYNA levels, while KYNA levels were unchanged in EKyn females, yet the activity levels of KAT I and KAT II were reduced. Our findings indicate that elevated prenatal kynurenine exposure elicits sex-specific changes in sleep-wake behavior, arousal, and KP metabolism.

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Reference:
Copper catalysis in organic synthesis – NCBI,
Special Issue “Fundamentals and Applications of Copper-Based Catalysts”

So far, in addition to halogen atoms, other non-metallic atoms can become part of the aromatic heterocycle, and the target ring system is still aromatic.Zhang, Hesheng; Fletcher, Mary T.; Avery, James W.; Kitching, William researched the compound: (S)-2-Bromosuccinic acid( cas:20859-23-8 ).Category: copper-catalyst.They published the article 《A suite of odd and even carbon-numbered spiroacetals in Bactrocera latifrons. Synthesis and stereochemistry》 about this compound( cas:20859-23-8 ) in Tetrahedron Letters. Keywords: spiroacetal synthesis stereochem. We’ll tell you more about this compound (cas:20859-23-8).

Female abdominal tips from the pestiferous fruit-fly species, Bactrocera latifrons (Hendel) provide a suite of odd and even 2-alkyl-8-methyl-1,7-dioxaspiro[5.5]undecanes (alkyl = Me, Et, Pr, nbutyl) which are shown by synthesis and enantioselective gas chromatog. to possess the (2S, 6R, 8S) stereochem.

Compounds in my other articles are similar to this one((S)-2-Bromosuccinic acid)Category: copper-catalyst, you can compare them to see their pros and cons in some ways,such as convenient, effective and so on.

Reference:
Copper catalysis in organic synthesis – NCBI,
Special Issue “Fundamentals and Applications of Copper-Based Catalysts”

So far, in addition to halogen atoms, other non-metallic atoms can become part of the aromatic heterocycle, and the target ring system is still aromatic.Tercenio, Quentin D.; Alexanian, Erik J. researched the compound: (S)-2-Bromosuccinic acid( cas:20859-23-8 ).Application of 20859-23-8.They published the article 《Stereospecific Nickel-Catalyzed Reductive Cross-Coupling of Alkyl Tosylate and Allyl Alcohol Electrophiles》 about this compound( cas:20859-23-8 ) in Organic Letters. Keywords: alkyl tosylate allyl alc nickel reductive cross coupling allylation; allyl alkane preparation enantioselective. We’ll tell you more about this compound (cas:20859-23-8).

A nickel-catalyzed reductive coupling of allyl alcs. with chiral, nonracemic alkyl tosylates was reported. This cross-coupling delivered valuable allylation products with high levels of stereospecificity across a range of substrates. The catalytic system consisted of a simple nickel salt in conjunction with a com. available reductant and importantly represented a rare example of a cross-coupling involving the C-O bonds of two electrophiles.

Compounds in my other articles are similar to this one((S)-2-Bromosuccinic acid)Application of 20859-23-8, you can compare them to see their pros and cons in some ways,such as convenient, effective and so on.

Reference:
Copper catalysis in organic synthesis – NCBI,
Special Issue “Fundamentals and Applications of Copper-Based Catalysts”

The preparation of ester heterocycles mostly uses heteroatoms as nucleophilic sites, which are achieved by intramolecular substitution or addition reactions. Compound: (S)-2-Bromosuccinic acid( cas:20859-23-8 ) is researched.Synthetic Route of C4H5BrO4.Polec, Iwona; Legocki, Jan; Kobes, Stanislaw; Morytz, Boleslaw published the article 《Enantiomers of O,O-dialkyl malathion analogs. Synthesis and toxicological characteristics》 about this compound( cas:20859-23-8 ) in Organika. Keywords: malathion analog preparation pesticide; dialkyldithiophosphoric acid ammonium salt preparation pesticide. Let’s learn more about this compound (cas:20859-23-8).

The title compounds [(RS), (R) or (S)-I; R = alkyl, cycloalkyl] were prepared by nucleophilic substitution of enantiomers or racemate of di-Et 2-bromosuccinate with O,O-dialkyldithiophosphoryl anions. Physicochem. properties of compounds I, and toxicol. characteristics of (R)-enantiomer of each I (LD50 i.p. for mouse, and LD50 for housefly), were given. Physicochem. characteristics of prepared ammonium salts of O,O-dialkyldithiophosphoric acids II, were also presented.

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Reference:
Copper catalysis in organic synthesis – NCBI,
Special Issue “Fundamentals and Applications of Copper-Based Catalysts”

Most of the natural products isolated at present are heterocyclic compounds, so heterocyclic compounds occupy an important position in the research of organic chemistry. A compound: 492-27-3, is researched, SMILESS is O=C(C1=NC2=CC=CC=C2C(O)=C1)O, Molecular C10H7NO3Journal, Article, Journal of neuroimmune pharmacology : the official journal of the Society on NeuroImmune Pharmacology called Kynurenic Acid Protects Against Reactive Glial-associated Reductions in the Complexity of Primary Cortical Neurons., Author is O’Reilly, Kate; O’Farrell, Katherine; Midttun, Oivind; Rakovets, Yuliia; David-Bercholz, Jennifer; Harkin, Andrew, the main research direction is Glia; Kynurenic acid; Kynurenine pathway; Primary cortical neurons.Reference of 4-Hydroxyquinoline-2-carboxylic Acid.

Brain glia produce neuroactive metabolites via tryptophan-kynurenine catabolism. A role for kynurenine pathway (KP) metabolites is proposed in reactive glial associated neurodegeneration. The aim of this investigation was to assess the role of KP induction and KP metabolites in driving reactive glial associated neuronal atrophy. Rat primary mixed glia, and enriched microglial and astroglial cultures were stimulated with IFNγ (10 ng/ml) for 24 hours. KP induction in mixed glial cells was confirmed by raised expression of the rate limiting KP enzyme indoleamine 2,3 dioxygenase (IDO) and raised concentrations of KP metabolites kynurenic acid (KYNA) and quinolinic acid (QUIN) in the conditioned media. Conditioned media was transferred onto immature (3 days) and mature (21 days) primary cortical neurons in vitro for 24 hours. IFNγ-stimulated mixed glial conditioned media reduced neurite outgrowth and complexity of both immature and mature neurons and co-localised expression of synaptic markers determined by immunocytochemistry. Pre-treatment of mixed glial cells with the IDO inhibitor, 1-methyltryptophan (1-MT) (L) prevented these effects of IFNγ-stimulated mixed glial conditioned media. KYNA increased complexity and synapse formation in mature cortical neurons and protected against reduced neuronal complexity and co-localised expression of synaptic markers induced by conditioned media from IFNγ-stimulated mixed glia and by treatment of neuronal cells with QUIN (1 µM). Overall, this study supports a role for the KP in driving neuronal atrophy associated with reactive glia and indicates that inhibition of the KP in glia, or raising the concentration of the astrocytic metabolite KYNA, protects against reactive microglial and QUIN-associated neuronal atrophy.

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Reference:
Copper catalysis in organic synthesis – NCBI,
Special Issue “Fundamentals and Applications of Copper-Based Catalysts”

The chemical properties of alicyclic heterocycles are similar to those of the corresponding chain compounds. Compound: 4-Hydroxyquinoline-2-carboxylic Acid, is researched, Molecular C10H7NO3, CAS is 492-27-3, about Kynurenic acid protects against mastitis in mice by ameliorating inflammatory responses and enhancing blood-milk barrier integrity, the main research direction is kynurenic acid mastitis inflammation blood milk barrier; Blood-milk barrier; Kynurenic acid (KYNA); Mastitis; NF-κB; Nrf2.Reference of 4-Hydroxyquinoline-2-carboxylic Acid.

Mastitis is one of the most serious diseases in humans and animals, especially in the modern dairy industry. Seeking safe and effective mastitis prevention strategies is urgent since food safety and drug residues in milk remain an enormous concern, despite the contribution of antibiotics to control mastitis. Kynurenic acid (KYNA), derived from the kynurenine pathway of tryptophan metabolism, has been shown to exhibit anti-inflammatory and immunomodulatory effects in many diseases. Recently, it was reported that impaired KYNA levels were associated with mastitis. However, the physiol. role of KYNA in mastitis has not yet been elucidated. Therefore, the aim of this study was to investigate the protective role of KYNA in pathogen-induced mastitis in mice, as well as the underlying mechanism of this effect. We first evaluated the effects of KYNA on LPS-induced mastitis in mice. Addnl., the underlying anti-inflammatory mechanism of KYNA was investigated in mammary epithelial cells (MMECs). Furthermore, we examined the effects of KYNA on S. aureus and E. coli induced mastitis in mice. Our results demonstrated that KYNA alleviated LPS-induced mastitis by reducing inflammatory responses and enhancing blood-milk barrier integrity. The fundamental mechanisms involved the inhibition of NF-κB and activation of Nrf2/Ho-1, which is probably mediated by G protein-coupled receptor 35 but not aryl hydrocarbon receptor. Notably, KYNA also protected against S. aureus and E. coli induced mastitis in mice. In conclusion, our results highlight the role of KYNA in mastitis and serve as a basis for using endogenous metabolite as a novel preventative or therapeutic strategy for disease intervention.

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Reference:
Copper catalysis in organic synthesis – NCBI,
Special Issue “Fundamentals and Applications of Copper-Based Catalysts”

Electric Literature of C10H7NO3. Aromatic compounds can be divided into two categories: single heterocycles and fused heterocycles. Compound: 4-Hydroxyquinoline-2-carboxylic Acid, is researched, Molecular C10H7NO3, CAS is 492-27-3, about Adenosine and kynurenic acid interactions: possible relevance for schizophrenia treatment?. Author is Beggiato, Sarah; Zuccarini, Mariachiara; Cassano, Tommaso; Borroto-Escuela, Dasiel Oscar; Di Iorio, Patrizia; Schwarcz, Robert; Fuxe, Kjell; Ferraro, Luca.

A review. In this article the considerations outlined indicate a possible relevance of adenosine and KYNA interactions in the pathophysiol. and treatment of schizophrenia. The present opinion paper was conceived to critically review possible interactions between adenosine and kynurenic acid (KYNA) in this context.

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Reference:
Copper catalysis in organic synthesis – NCBI,
Special Issue “Fundamentals and Applications of Copper-Based Catalysts”

The preparation of ester heterocycles mostly uses heteroatoms as nucleophilic sites, which are achieved by intramolecular substitution or addition reactions. Compound: 4-Hydroxyquinoline-2-carboxylic Acid( cas:492-27-3 ) is researched.Application of 492-27-3.Li, Hui; Cui, Lanchong; Zhang, Guolei; Zhang, Mengmeng; Jiao, Lili; Wu, Wei published the article 《[Quantitative analysis of tryptophan and its metabolites in urine by ultra performance liquid chromatography-tandem mass spectrometry].》 about this compound( cas:492-27-3 ) in Se pu = Chinese journal of chromatography. Keywords: pre-column derivation; tryptophan-kynurenine pathway; ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS); urine. Let’s learn more about this compound (cas:492-27-3).

Tryptophan (Trp), also known as α-amino β-indolepropionic acid, is an essential amino acid, which is involved in various physiological processes. Studies have shown that tumors, infectious diseases, and neurological diseases are accompanied by Trp-related metabolic disorders. Understanding the excretion of Trp and its metabolites in normal individuals is of great significance for treating Trp-related diseases and monitoring the health. A rapid quantitative method was developed based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Further, this method was applied to the simultaneous determination of Trp and its metabolites, including kynurenine (Kyn), kynurenic acid (KA), 3-hydroxykynurenine (3-OH-Kyn), 3-hydroxyanthranilic acid (3-OH-AA), xanthurenic acid (XA), 5-hydroxytryptamine (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA). The excretion and amount of target compounds in random urine samples collected from healthy participants were studied using this method. Urine samples were collected from healthy male volunteers (between 20-22 years old) without any diet and exercise restrictions. Urine samples were collected between 11∶00-13∶00 daily for 10 d. Thereafter, the urine samples were diluted, centrifuged, and subjected to pre-column derivatization with dansyl chloride (DNS-Cl). Caffeic acid (CA) was used as the internal control. Later, the derivatives were detected using triple quadrupole mass spectrometry with electron pray ionization (ESI) in positive and multi reaction monitoring (MRM) modes. The samples were separated using a Thermo C18 column (50 mm×3 mm, 2.7 μm) with 0.1% aqueous formic acid aqueous solution and methanol as mobile phases at a flow rate of 0.2 mL/min. The three most abundant ions for each derivative were selected for downstream analysis, and the internal control was used for quantification. The polarity and molecular weight of the compounds were found to be altered effectively after DNS-Cl derivatization treatment. The dansyl group effectively altered the polarities of the derivatives, such that their retention behaviors in the reverse elution system were similar and they were well separated. The interference due to impurities was effectively eliminated using the MRM mode. The results showed significant linear correlation, since the correlation coefficients were greater than 0.9740. The recoveries were between 93.24%-107.65%, and the LODs were 0.005-0.5 ng/mL for the eight compounds. Trp prototype and the seven target metabolites, including 3-OH-Kyn, 3-OH-AA, XA, Kyn, KA, 5-HIAA, and 5-HT generated through Trp-5-HT and Trp-Kyn pathways were detected in the urine samples. These results indicated that Trp was excreted in a prototypic form or after being metabolized. The level of the target compounds in random urine samples of individuals were 0.99-3.72 (3-OH-Kyn), 2.51-21.11 (3-OH-AA), 0.25-1.12 (XA), 0.15-1.53 (Kyn), 0.24-2.58 (KA), 0-0.31 (5-HT), and 2.2-17.94 (5-HIAA) μg/mL. For the same individual, in the state of physical health, the fluctuations of Trp and its metabolites in urine were large. Due to these large fluctuations in the absolute content, the difference between individuals was not significant. The data generated using 70 urine samples revealed that the amount of excreted Trp being metabolized was 124%-268% of prototype, which further indicated that the excretion after metabolism was the major underlying mechanism. Upon comparing the levels of metabolites in the Trp-5-HT and Trp-Kyn pathways, the results indicated that the levels of 3-OH-AA and 3-OH-Kyn generated upon Trp degradation through the Kyn pathway was higher than those of the other products. Trp was degraded via Kyn pathway to produce 3-OH-AA, which was the main metabolite of Trp found to be present in the body. This manuscript detected the levels of Trp and its metabolites, as well as summarized the characteristics of excretion using random urine samples, which could provide valuable information for clinical practice.

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Reference:
Copper catalysis in organic synthesis – NCBI,
Special Issue “Fundamentals and Applications of Copper-Based Catalysts”

SDS of cas: 20859-23-8. The reaction of aromatic heterocyclic molecules with protons is called protonation. Aromatic heterocycles are more basic than benzene due to the participation of heteroatoms. Compound: (S)-2-Bromosuccinic acid, is researched, Molecular C4H5BrO4, CAS is 20859-23-8, about A versatile ternary ion pair complex of 2′-amino-1,1′-binaphthalen-2-ol for sensing enantiomers and assignment of absolute configuration. Author is Lakshmipriya, Anamalagundam; Sumana, Gaonkar; Suryaprakash, Nagaraja Rao.

2′-Amino-1,1′-binaphthalen-2-ol (NOBIN) serves as a versatile chiral solvating agent (CSA) in the presence of trifluoromethanesulfonic acid (TFMS). The formation of a ternary complex was established by NMR, UV-visible, fluorescence and IR studies. The mechanism of interactions among the three components in the ternary complex is proposed and the ternary complex structures of different diastereomers were established by DFT based theor. calculations The present protocol has its ubiquity not only in the anal. of the enantiomeric composition of mols. possessing diverse functionalities, but also in determining the stereospecific assignment of hydroxy acids.

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Reference:
Copper catalysis in organic synthesis – NCBI,
Special Issue “Fundamentals and Applications of Copper-Based Catalysts”