Tag: M.W:100-200

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: 20859-23-8, is researched, SMILESS is O=C(O)[C@@H](Br)CC(O)=O, Molecular C4H5BrO4Journal, Chromatographia called Super/subcritical fluid chromatography separations with four synthetic polymeric chiral stationary phases, Author is Han, X.; Berthod, A.; Wang, C.; Huang, K.; Armstrong, D. W., the main research direction is supercritical fluid chromatog amide containing polymer silica chiral phase; subcritical fluid chromatog amide containing polymer silica chiral phase.Category: copper-catalyst.

New synthetic polymeric chiral selectors were developed recently as chiral stationary phases. They were tested with supercritical fluid mobile phases made of CO2 plus an alc. modifier and 0.2% volume/volume trifluoroacetic acid. The polymeric N,N’-(1S,2S)-1,2-cyclohexanediyl-bis-2-propenamide (P-CAP), the polymeric N,N’-[(1R,2R)-1,2-diphenyl-1,2-ethanediyl] bis-2-propenamide (P-CAP-DP), the polymeric trans-9,10-dihydro-9,10-ethanoanthracene-(11S,12S)-11,12-dicarboxylic acid bis-4-vinylphenylamide (DEABV) and the polymeric N,N’-[(1R,2R)-1,2-diphenyl-1,2-ethanediyl] bis-4-vinylbenzamide (DPEVB) were bonded to 5 μm silica particles and used to prepare four columns that were tested with a set of 88 chiral compounds with a wide variety of chem. functionalities. All 88 test compounds were separated on one or more of these related polymeric CSPs. Forty-three enantiomeric pairs were separated in SFC conditions by only one of the CSPs. Twenty pairs were separated by two CSPs and 18 and 7 enantiomeric pairs were separated by 3 and all 4 CSPs, resp. The three P-CAP, P-CAP-DP and DEABV CSPs have equivalent success being able to sep. 49 enantiomeric pairs of the studied set with resp. 12, 14 and 20 at baseline (Rs > 1.5). The DPEVB CSP was significantly less efficient separating only 18 chiral compounds with only one at baseline. The great advantage of the SFC mobile phases is the rapid separation, which most achieved in <5 min. 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”

Safety of 4-Hydroxyquinoline-2-carboxylic Acid. 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: 4-Hydroxyquinoline-2-carboxylic Acid, is researched, Molecular C10H7NO3, CAS is 492-27-3, about Visualising UV-A light-induced damage to plasma membranes of eye lens. Author is Sherin, Peter S.; Vysniauskas, Aurimas; Lopez-Duarte, Ismael; Ogilby, Peter R.; Kuimova, Marina K..

An eye lens is constantly exposed to the solar UV radiation, which is considered the most important external source of age-related changes to eye lens constituents. The accumulation of modifications of proteins and lipids with age can eventually lead to the development of progressive lens opacifications, such as cataracts. Though the impact of solar UV radiation on the structure and function of proteins is actively studied, little is known about the effect of photodamage on plasma membranes of lens cells. In this work we exploit Fluorescence Lifetime Imaging Microscopy (FLIM), together with viscosity-sensitive fluorophores termed mol. rotors, to study the changes in viscosity of plasma membranes of porcine eye lens resulting from two different types of photodamage: Type I (electron transfer) and Type II (singlet oxygen) reactions. We demonstrate that these two types of photodamage result in clearly distinct changes in viscosity – a decrease in the case of Type I damage and an increase in the case of Type II processes. Finally, to simulate age-related changes that occur in vivo, we expose an intact eye lens to UV-A light under anaerobic conditions. The observed decrease in viscosity within plasma membranes is consistent with the ability of eye lens constituents to sensitize Type I photodamage under natural irradiation conditions. These changes are likely to alter the transport of metabolites and predispose the whole tissue to the development of pathol. processes such as cataracts.

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

Narala, Siva Ganesh; Nagalatha, G.; Venkat Narsaiah, A. published the article 《Stereoselective total synthesis of C2-symmetric natural products pyrenophorol and its derivatives》. Keywords: pyrenophorol stereoselective synthesis regioselective epoxide opening reduction Pinnick oxidation; Mitsunobu dilactonization pyrenophorol stereoselective synthesis; CBS reduction; Macrodiolide; Pinnick oxidation; antimicrobiol agent; dilactonization.They researched the compound: (S)-2-Bromosuccinic acid( cas:20859-23-8 ).Recommanded Product: 20859-23-8. Aromatic heterocyclic compounds can be divided into two categories: single heterocyclic and fused heterocyclic. In addition, there is a lot of other information about this compound (cas:20859-23-8) here.

A stereoselective total synthesis of 16-membered C2-sym. macrodiolide pyrenophorol (I, R = H), tetrahydropyrenophorol (II) and 4,4-diacetylpyrenophorol I (R = COMe) have been accomplished. The synthesis started from com. available L-Aspartic acid and the key reactions involved are regioselective epoxide opening, CBS reduction, Pinnick oxidation and Mitsunobu dilactonization.

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

The reaction of an aromatic heterocycle with a proton is called a protonation. One of articles about this theory is 《Stereochemical studies. XXIV. Stereoisomeric (benzoylmercapto)succinic and (benzoylmercapto)succinamic acids》. Authors are Holmberg, Bror.The article about the compound:(S)-2-Bromosuccinic acidcas:20859-23-8,SMILESS:O=C(O)[C@@H](Br)CC(O)=O).HPLC of Formula: 20859-23-8. Through the article, more information about this compound (cas:20859-23-8) is conveyed.

cf. C.A. 35, 5465.3. BzSH (6.9 g.) and 5.8 g. maleic acid in hot AcOH yield 7.6 g. DL-HCO2CH(SBz)CH2CO2H (I), m. 177-82°. L(-)-HCO2CH(SBz)CH2CO2H, sintering 175° and m. 182-3°, [α]D20 -6°, [α]D20 -123° (c 0.5028, Me2CO), [M]D20 -315°, was prepared from BzSH, Na2CO3, and L(-)-CHBr(CO2H)CH2CO2H (II) in H2O, while the D(+)-isomer (III), m. 176-80°, [α]D20 6°, [α]D20 124° (c 0.5028, Me2CO), [M]D20 315°, results from the same starting materials when alc.-H2O, and no Na2CO3 is used. III with concentrated NH4OH yields BzNH2 and some dithiodimalic acid, m. 164-6°, [α]D20 257° (Me2CO). PhCSNH2 and II in EtOAc yield PhC(NH2Br)SCH(CO2H)CH2CO2H, m. 205°, with foaming; this in turn is converted by heating in H2O to S.CPh:N.CO.CHCH2CO2H, m. 195-7°. From DL-NH2COCHICH2CO2H with Na2CO3 and BzSH in H2O was prepared DL-BzSCH(CO2H)CH2CONH2, m. 174-5°, while the D(+)-isomer (IV), m. 164-5°, [α]D20 105°, [M]D20 266°, was prepared from L(-)-NH2COCHBrCH2CO2H and BzSK in Na2CO3 solution The free acid, HSCH(CO2H)CH2CONH2 m. 115-16°, [α]D20 84° (c 0.4, Me2CO), was prepared by treating IV with concentrated NH4OH, distilling in vacuo, and acidifying with H2SO4. The course of these reactions may be explained by the mechanisms proposed by Fredga (The Svedberg-Buch 1944, p. 261).

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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, International Journal of Molecular Sciences called Effective activation by kynurenic acid and its aminoalkylated derivatives on M-type K+ current, Author is Lo, Yi-Ching; Lin, Chih-Lung; Fang, Wei-Yu; Lorinczi, Balint; Szatmari, Istvan; Chang, Wan-Hsuan; Fulop, Ferenc; Wu, Sheng-Nan, the main research direction is kynurenic acid potassium membrane potential aminoalkylation hippocampus; M-type K+ current; action potential; hippocampal neuron; kynurenic acid; kynurenic acid derivative; pituitary cell.Category: copper-catalyst.

Kynurenic acid (KYNA, 4-oxoquinoline-2-carboxylic acid), an intermediate of the tryptophan metabolism, has been recognized to exert different neuroactive actions; however, the need of how it or its aminoalkylated amide derivative N-(2-(dimethylamino)ethyl)-3-(morpholinomethyl)-4-oxo-1,4-dihydroquinoline-2-carboxamide (KYNA-A4) exerts any effects on ion currents in excitable cells remains largely unmet. In this study, the investigations of how KYNA and other structurally similar KYNA derivatives have any adjustments on different ionic currents in pituitary GH3 cells and hippocampal mHippoE-14 neurons were performed by patch-clamp technique. KYNA or KYNA-A4 increased the amplitude of M-type K+ current (IK(M)) and concomitantly enhanced the activation time course of the current. The EC50 value required for KYNA- or KYNA-A4 -stimulated IK(M) was yielded to be 18.1 or 6.4μM, resp. The presence of KYNA or KYNA-A4 shifted the relationship of normalized IK(M)-conductance vs. membrane potential to more depolarized potential with no change in the gating charge of the current. The voltage-dependent hysteretic area of IK(M) elicited by long-lasting triangular ramp pulse was observed in GH3 cells and that was increased during exposure to KYNA or KYNA-A4. In cell-attached current recordings, addition of KYNA raised the open probability of M-type K+ channels, along with increased mean open time of the channel. Cell exposure to KYNA or KYNA-A4 mildly inhibited delayed-rectifying K+ current; however, neither erg-mediated K+ current, hyperpolarization-activated cation current, nor voltage-gated Na+ current in GH3 cells was changed by KYNA or KYNA-A4. Under whole-cell, current-clamp recordings, exposure to KYNA or KYNA-A4 diminished the frequency of spontaneous action potentials; moreover, their reduction in firing frequency was attenuated by linopirdine, yet not by iberiotoxin or apamin. In hippocampal mHippoE-14 neurons, the addition of KYNA also increased the IK(M) amplitude effectively. Taken together, the actions presented herein would be one of the noticeable mechanisms through which they modulate functional activities of excitable cells occurring in vivo.

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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.Touet, Joel; Ruault, Thierry; Brown, Eric researched the compound: (S)-2-Bromosuccinic acid( cas:20859-23-8 ).Synthetic Route of C4H5BrO4.They published the article 《Resolving agents. Part 1. (R)-(-)-2-Amino-1-benzyloxybutane, a new base for the resolution of racemic acids》 about this compound( cas:20859-23-8 ) in Synthetic Communications. Keywords: aminobenzyloxybutane resolution carboxylic acid. We’ll tell you more about this compound (cas:20859-23-8).

Treatment of the readily available (R)-(-) enantiomer of 2-aminobutan-1-ol with sodium hydride followed by benzyl chloride afforded (R)-(-)-H2NCHEtCH2OCH2Ph. The latter was successfully used for the resolution of racemic HO2CCHRCH2CO2H (R = Ph, Me, Br) as well as racemic I (Y = H, OMe).

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

Related Products of 492-27-3. 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: 4-Hydroxyquinoline-2-carboxylic Acid, is researched, Molecular C10H7NO3, CAS is 492-27-3, about A comprehensive study on the relieving effect of Lilium brownii on the intestinal flora and metabolic disorder in p-chlorphenylalanine induced insomnia rats. Author is Si, Yanpo; Wei, Wenjun; Chen, Xiaohui; Xie, Xiaolong; Guo, Tao; Sasaki, Yohei; Zhang, Youbo; Wang, Lili; Zhang, Fei; Feng, Shuying.

ContextThe bulb of Lilium brownii F. E. Brown (Liliaceae) (LB) is a common Chinese medicine to relieve insomnia. ObjectiveTo investigate the mol. mechanism of LB relieving insomnia. Materials and methodsInsomnia model was induced by i.p. injection p-chlorophenylalanine (PCPA) in Wistar rats. Rats were divided into three groups: Control, PCPA (400 mg/kg, i.p. 2 days), LB (598.64 mg/kg, oral 7 days). The levels of 5-hydroxytryptamine (5-HT), norepinephrine (NE), melatonin (MT), and the expression of GABAA, 5-HT1A and MT receptors, as well as pathol. changes in hypothalamus, were evaluated. 16S rDNA sequencing and UPLC-MS/MS were used to reveal the change of the intestinal flora and metabolic profile. ResultsThe adverse changes in the abundance and diversity of intestinal flora and faecal metabolic phenotype altered by PCPA in rats were reversed after LB treatment, accompanied by the up-regulated levels of 5-HT as 8.14 ng/mL, MT as 16.16 pg/mL, 5-HT1A R and GABAA R, down-regulated level of NE as 0.47 ng/mL, and the improvement of pathol. phenomena of cells in the hypothalamus. And the arachidonic acid metabolism and tryptophan metabolism pathway most significantly altered by PCPA were markedly regulated by LB. Besides, it was also found that LB reduced the levels of kynurenic acid related to psychiatric disorders and trimethylamine-N-oxide associated with cardiovascular disease. ConclusionThe mechanism of LB relieving insomnia involves regulating flora and metabolites to resemble the control group. As a medicinal and edible herb, LB could be considered for development as a health-care food to relieve increasing insomniacs in the future.

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

Recommanded Product: (S)-2-Bromosuccinic acid. The fused heterocycle is formed by combining a benzene ring with a single heterocycle, or two or more single heterocycles. Compound: (S)-2-Bromosuccinic acid, is researched, Molecular C4H5BrO4, CAS is 20859-23-8, about The divergent asymmetric synthesis of kalafungin, 5-epi-frenolicin B and related pyranonaphthoquinone antibiotics. Author is Donner, Christopher D..

A divergent, asym. method for the synthesis of pyranonaphthoquinones is reported. The synthetic strategy applies a Staunton-Weinreb annulation between substituted ortho-toluates and the (R)-pyran-2-one I to construct the key naphthopyranone intermediates, e.g., II. Stereoselective introduction of either a Me or Pr C5 alkyl substituent by use of Grignard addition/silane-mediated reduction and a sequence of oxidations gave a series of pyranonaphthoquinones including kalafungin (III), 5-epi-frenolicin B (IV; R1 = Pr-n, R2 = H), and 5-epi-9-methoxykalafungin (IV; R1 = Me, R2 = OMe).

In some applications, this compound(20859-23-8)Recommanded Product: (S)-2-Bromosuccinic acid is unique.If you want to know more details about this compound, you can contact with the author or consult more relevant literature.

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

Joshi, Priyanka; Perni, Michele; Limbocker, Ryan; Mannini, Benedetta; Casford, Sam; Chia, Sean; Habchi, Johnny; Labbadia, Johnathan; Dobson, Christopher M.; Vendruscolo, Michele published the article 《Two human metabolites rescue a C. elegans model of Alzheimer’s disease via a cytosolic unfolded protein response》. Keywords: cytosolic unfolded protein response metabolite Caenorhabditis Alzheimers disease.They researched the compound: 4-Hydroxyquinoline-2-carboxylic Acid( cas:492-27-3 ).COA of Formula: C10H7NO3. Aromatic heterocyclic compounds can be divided into two categories: single heterocyclic and fused heterocyclic. In addition, there is a lot of other information about this compound (cas:492-27-3) here.

Age-related changes in cellular metabolism can affect brain homeostasis, creating conditions that are permissive to the onset and progression of neurodegenerative disorders such as Alzheimer’s and Parkinson’s diseases. Although the roles of metabolites have been extensively studied with regard to cellular signaling pathways, their effects on protein aggregation remain relatively unexplored. By computationally analyzing the Human Metabolome Database, we identified two endogenous metabolites, carnosine and kynurenic acid, that inhibit the aggregation of the amyloid beta peptide (Aβ) and rescue a C. elegans model of Alzheimer’s disease. We found that these metabolites act by triggering a cytosolic unfolded protein response through the transcription factor HSF-1 and downstream chaperones HSP40/J-proteins DNJ-12 and DNJ-19. These results help rationalise previous observations regarding the possible anti-ageing benefits of these metabolites by providing a mechanism for their action. Taken together, our findings provide a link between metabolite homeostasis and protein homeostasis, which could inspire preventative interventions against neurodegenerative disorders.

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

In organic chemistry, atoms other than carbon and hydrogen are generally referred to as heteroatoms. The most common heteroatoms are nitrogen, oxygen and sulfur. Now I present to you an article called Optical rotatory dispersion and absolute configuration. Part 20. Chiroptical properties of α-substituted succinic acids. Conformation and absolute configuration, published in 1977, which mentions a compound: 20859-23-8, mainly applied to CD conformation succinate, Synthetic Route of C4H5BrO4.

The effect of conformational preference on the chiroptical properties of α-substituted succinic acids and esters was studied using variable temperature CD in solvents of different polarity. When R1 in the ester RO2CCH2CHR1CO2R (I) is alkyl or halogen, the preferred conformation is II (X = H, Y = R1, Z = CH2CO2R) with the CH2CO2R group eclipsed by the CO bond, whereas when R1 in I is OH, OMe, or NH2, the major conformer is II (X = CH2CO2R, Y = H, Z = R1), in which the heteroatom is eclipsed by the CO bond. In both cases, conformation II (X = R1, Y = CH2CO2R, Z = H) is least favored, mainly on steric grounds. The results when R1 = Cl or Br in I do not support previously proposed conclusions (Listowsky, I. et al., 1970) and an alternative explaination is given. In the resultant octant projection, the sign of the Cotton effect for I will be determined by the position of the groups X and Y in the back octants, and since one of these is always H in the 2 favored conformations, the sign is actually determined by the position of the other group. The octant projection predicts successfully the sign of the ellipticity of the n→π* transition for any α-substituted succinic acid or ester with the appropriate substituent R1, and applied also to simple alkanoic acids and esters with the same substituents.

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