Pyrazines

Recently I am researching about BIOLOGICAL EVALUATION; MOLECULAR DOCKING; 20S PROTEASOME; DESIGN; DERIVATIVES; IDENTIFICATION; DEGRADATION; GENERATION; APOPTOSIS; MYELOMA, Saw an article supported by the National Natural Science Foundation of ChinaNational Natural Science Foundation of China (NSFC); Key Project of Zhejiang Provincial Natural Science Foundation of China; Science and Technology Commission of Shanghai MunicipalityScience & Technology Commission of Shanghai Municipality (STCSM); Strategic Priority Research Program of the Chinese Academy of SciencesChinese Academy of Sciences; National Major Scientific and Technological Special Project for Significant New Drugs Development. Published in ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER in ISSY-LES-MOULINEAUX ,Authors: Dong, XW; Zhang, JK; Xu, L; Che, JX; Cheng, G; Hu, XB; Sheng, L; Gao, AH; Li, J; Liu, T; Hu, YZ; Zhou, YB. The CAS is 98-97-5. Through research, I have a further understanding and discovery of Pyrazine-2-carboxylic acid. Category: Pyrazines

The potential of specific proteasome inhibitors to act as anti-cancer agents has attracted intensive investigations. The proteasome can be covalently inhibited by epoxyketone derivatives via a two-step reaction. Several computational approaches have been developed to mimic the covalent binding event. Compound 1 composed of a six-membered heterocyclic ring was designed by using covalent docking. With a possible different binding mode from the clinical compound Carfilzomib, it occupied the 55 pocket of 20S proteasome and showed favorable inhibitory activity. Subsequently optimization and evaluation were taken place. Among these compounds, 11h demonstrated extraordinary in vitro inhibitory activity and selectivity, and good in vivo proteasome inhibitory activity, a favorable pharmacokinetic profile and xenograft tumor inhibition. The possible binding pattern of compound 11h against proteasome was further fully explored via calculations, providing a theoretical basis for finding potent proteasome inhibitors. (C) 2018 Elsevier Masson SAS. All rights reserved.

Category: Pyrazines. Bye, fridends, I hope you can learn more about C5H4N2O2, If you have any questions, you can browse other blog as well. See you lster.

Reference:
Patent; Chevron Research Company; US4732894; (1988); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

In 2019 MOLECULES published article about STANDARD MOLAR ENTHALPY; STRUCTURE-PROPERTY RELATIONSHIPS; THERMODYNAMIC PROPERTIES; IONIC LIQUIDS; THERMOPHYSICAL PROPERTIES; TEMPERATURE-RANGE; GROUP ADDITIVITY; VAPOR-PRESSURES; THERMAL-ANALYSIS; COMPUTATIONAL THERMOCHEMISTRY in [Naef, Rudolf] Univ Basel, Dept Chem, CH-4003 Basel, Switzerland in 2019, Cited 287. The Name is Pyrazine-2-carboxylic acid. Through research, I have a further understanding and discovery of 98-97-5. Name: Pyrazine-2-carboxylic acid

A universally applicable method for the prediction of the isobaric heat capacities of the liquid and solid phase of molecules at 298.15 K is presented, derived from their true volume. The molecules’ true volume in A(3) is calculated on the basis of their geometry-optimized structure and the Van-der-Waals radii of their constituting atoms by means of a fast numerical algorithm. Good linear correlations of the true volume of a large number of compounds encompassing all classes and sizes with their experimental liquid and solid heat capacities over a large range have been found, although noticeably distorted by intermolecular hydrogen-bond effects. To account for these effects, the total amount of 1303 compounds with known experimental liquid heat capacities has been subdivided into three subsets consisting of 1102 hydroxy-group-free compounds, 164 monoalcohols/monoacids, and 36 polyalcohols/polyacids. The standard deviations for Cp(liq,298) were 20.7 J/mol/K for the OH-free compunds, 22.91 J/mol/K for the monoalcohols/monoacids and 16.03 J/mol/K for the polyols/polyacids. Analogously, 797 compounds with known solid heat capacities have been separated into a subset of 555 OH-free compounds, 123 monoalcohols/monoacids and 119 polyols/polyacids. The standard deviations for Cp(sol,298) were calculated to 23.14 J/mol/K for the first, 21.62 J/mol/K for the second, and 19.75 J/mol/K for the last subset. A discussion of structural and intermolecular effects influencing the heat capacities as well as of some special classes, in particular hydrocarbons, ionic liquids, siloxanes and metallocenes, has been given. In addition, the present method has successfully been extended to enable the prediction of the temperature dependence of the solid and liquid heat capacities in the range between 250 and 350 K.

Name: Pyrazine-2-carboxylic acid. Welcome to talk about 98-97-5, If you have any questions, you can contact Naef, R or send Email.

Reference:
Patent; Chevron Research Company; US4732894; (1988); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Name: Pyrazine-2-carboxylic acid. Recently I am researching about MYCOBACTERIUM-TUBERCULOSIS; CATALASE-PEROXIDASE; SUSCEPTIBILITY; ARTEMISININ; ANTIMALARIAL; RESISTANCE; KATG, Saw an article supported by the CSIR Thematic Program Fund; South African Medical Research CouncilUK Research & Innovation (UKRI)Medical Research Council UK (MRC) [MRC-RFA-UFSP-01-2013]; SAMRCUK Research & Innovation (UKRI)Medical Research Council UK (MRC). Published in BENTHAM SCIENCE PUBL LTD in SHARJAH ,Authors: van der Westhuyzen, CW; Haynes, RK; Panayides, JL; Wiid, I; Parkinson, CJ. The CAS is 98-97-5. Through research, I have a further understanding and discovery of Pyrazine-2-carboxylic acid

Background: With few exceptions, existing tuberculosis drugs were developed many years ago and resistance profiles have emerged. This has created a need for new drugs with discrete modes of action. There is evidence that tuberculosis (like other bacteria) is susceptible to oxidative pressure and this has yet to be properly utilised as a therapeutic approach in a manner similar to that which has proven highly successful in malaria therapy. Objective: To develop an alternative approach to the incorporation of bacterial siderophores that results in the creation of antitubercular peroxidic leads for subsequent development as novel agents against tuberculosis. Methods: Eight novel peroxides were prepared and the antitubercular activity (H(37)Rv) was compared to existing artemisinin derivatives in vitro. The potential for toxicity was evaluated against the L6 rat skeletal myoblast and HeLa cervical cancer lines in vitro. Results: The addition of a pyrimidinyl residue to an artemisinin or, preferably, a tetraoxane peroxidic structure results in antitubercular activity in vitro. The same effect is not observed in the absence of the pyrimidine or with other heteroaromatic substituents. Conclusion: The incorporation of a pyrimidinyl residue adjacent to the peroxidic function in an organic peroxide results in anti-tubercular activity in an otherwise inactive peroxidic compound. This will be a useful approach for creating oxidative drugs to target tuberculosis.

Name: Pyrazine-2-carboxylic acid. Bye, fridends, I hope you can learn more about C5H4N2O2, If you have any questions, you can browse other blog as well. See you lster.

Reference:
Patent; Chevron Research Company; US4732894; (1988); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Quality Control of 1953146-81-0. Today I’d like to introduce a new chemical compound, CAS is 1953146-81-0, Name is 36-(((2R,3R,4R,5R,6R)-3-Acetamido-4,5-dihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)oxy)-21,21-bis((3-((3-(5-(((2R,3R,4R,5R,6R)-3-acetamido-4,5-dihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl)oxy)pentanamido)propyl)amino)-3-oxopropoxy)methyl)-19,26,32-trioxo-4,7,10,13,16,23-hexaoxa-20,27,31-triazahexatriacontan-1-oic acid, Formula is C75H134N10O35, Molecular Weight is 1735.91g/mol. Because of its complex structure and huge molecular weight, this compound is rarely understood. Now let me introduce some knowledge about its synthesis.

The general reactant of this compound is (2S,4R)-2-[[Bis(4-methoxyphenyl)phenylmethoxy]methyl]-4-hydroxy-λ-oxo-N-[2-[3-oxo-3-[[3-[[1-oxo-5-[[3,4,6-tri-O-acetyl-2-(acetylamino)-2-deoxy-β-D-galactopyranosyl]oxy]pentyl]amino]propyl]amino]propoxy]-1,1-bis[[3-oxo-3-[[3-[[1-oxo-5-[[3,4,6-tri-O-acetyl-2-(acetylamino)-2-deoxy-β-D-galactopyranosyl]oxy]pentyl]amino]propyl]amino]propoxy]methyl]ethyl]-1-pyrrolidinedodecanamide, Reagents is Triethylamine, Catalyst(4-(Dimethylamino)pyridine), Solvent is Acetonitrile, Products 1-[(3R,5S)-5-[[Bis(4-methoxyphenyl)phenylmethoxy]methyl]-1-[1,12,19,25-tetraoxo-14,14-bis[[3-oxo-3-[[3-[[1-oxo-5-[[3,4,6-tri-O-acetyl-2-(acetylamino)-2-deoxy-β-D-galactopyranosyl]oxy]pentyl]amino]propyl]amino]propoxy]methyl]-29-[[3,4,6-tri-O-acetyl-2-(acetylamino)-2-deoxy-β-D-galactopyranosyl]oxy]-16-oxa-13,20,24-triazanonacos-1-yl]-3-pyrrolidinyl] butanedioate, Yield: 100%, Synthetic Methods procedure :1. Dissolve reactant ( 29.20 g, 12.14 mmol ) , succinic anhydride ( 2.45 g, 24.28 mmol ) , polystyrene supported DMAP ( PS-DMAP, 16 g, 1.49 mmol/g, 2 equiv. ) and Et3N ( 10 mL ) in DCM and stir for 48 hours., 2. Filter the reaction mixture, dilute with DCM and wash with saturated brine., 3. Dry the organic layer over anhydrous Na2SO4., 4. Remove solvents and volatiles under reduced pressure., 5. Dry the residue under high vacuum overnight., Transfornation (Alcoholysis of Anhydrides.

Quality Control of 1953146-81-0. I’m so glad you had the patience to read the whole article, if you want know more about 1953146-81-0, you can browse my other blog.

Reference:
CAS Reaction Number: 31-355-CAS-9994399,
,CAS Method Number: 3-614-CAS-3165786

Authors Lei, JC; Ruan, YX; Luo, S; Yang, JS in WILEY-V C H VERLAG GMBH published article about PROTECTING GROUP; OLIGOSACCHARIDES; GLYCANS; TRI in [Lei, Jin-Cai; Ruan, Yu-Xiong; Luo, Sheng; Yang, Jin-Song] Sichuan Univ, West China Hosp, Key Lab Drug Targeting & Drug Delivery Syst, Sichuan Engn Lab Plant Sourced Drug,Educ Minist, Chengdu 610041, Sichuan, Peoples R China; [Lei, Jin-Cai; Ruan, Yu-Xiong; Luo, Sheng; Yang, Jin-Song] Sichuan Univ, West China Hosp, West China Sch Pharm, Sichuan Res Ctr Drug Precis Ind Technol, Chengdu 610041, Sichuan, Peoples R China; [Lei, Jin-Cai; Ruan, Yu-Xiong; Luo, Sheng; Yang, Jin-Song] Sichuan Univ, West China Hosp, State Key Lab Biotherapy, Chengdu 610041, Sichuan, Peoples R China in 2019, Cited 47. Name: Pyrazine-2-carboxylic acid. The Name is Pyrazine-2-carboxylic acid. Through research, I have a further understanding and discovery of 98-97-5

The tuning effect of C3-ester groups on the glycosylation stereochemistry of L-rhamnopyranose (L-Rha) ethyl thioglycoside donors is described. On one hand, the L-Rha thioglycoside donors carrying 3-O-arylcarbonyl or levulinoyl group undergo highly alpha-selective glycosylation to afford a wide variety of alpha-L-rhamnoside products in high chemical yields. On the other hand, the glycosylation of the 3-O-4-nitropicoloyl and 2-pyrazinecarbonyl group substituted L-Rha thioglycosides displays beta-stereoselectivity. Only or predominant beta anomeric products are obtained when these L-Rha donors couple with the primary or reactive secondary acceptors, while the beta-selectivity may decrease significantly when these donors react with less reactive secondary alcohols. The synthetic utility of the newly developed alpha- and beta-directing L-Rha donors 1h and 1e has been demonstrated by the efficient synthesis of a structurally unique trisaccharide 9, which is derived from the cell wall polysaccharide of Sphaerotilus natans.

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Reference:
Patent; Chevron Research Company; US4732894; (1988); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

An article Zirconium-Containing Organic-Inorganic Nanohybrid as a Highly Efficient Catalyst for the Selective Synthesis of Biomass-Derived 2,5-Dihydroxymethylfuran in Isopropanol WOS:000538735600030 published article about TRANSFER HYDROGENATION; LEVULINIC ACID; ELECTROCATALYTIC HYDROGENATION; REDUCTIVE ETHERIFICATION; FURFURYL ALCOHOL; CONVERSION; TRANSFORMATION; HMF; 2,5-BIS(HYDROXYMETHYL)FURAN; DERIVATIVES in [Hu, Lei; Liu, Su; Song, Jie; Jiang, Yetao; He, Aiyong; Xu, Jiaxing] Huaiyin Normal Univ, Jiangsu Collaborat Innovat Ctr Reg Modern Agr & E, Sch Chem & Chem Engn, Jiangsu Key Lab Biomass Based Energy & Enzyme Tec, Huaian 223300, Peoples R China in 2020, Cited 82. The Name is Pyrazine-2-carboxylic acid. Through research, I have a further understanding and discovery of 98-97-5. HPLC of Formula: C5H4N2O2

By the simple assembly of zirconium tetrachloride and diethylenetriaminepentaacetic acid (DTPA), a new acid-base bifunctional zirconium-containing organic-inorganic nanohybrid catalyst (Zr-DTPA) was successfully prepared in this work, and then used for the catalytic transfer hydrogenation (CTH) of biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-dihydroxymethylfuran (DHMF) using isopropanol as the in situ hydrogen donor and reaction solvent. Satisfactorily, 98.7% HMF conversion and 95.2% DHMF yield could be achieved in 4 h at a moderate reaction temperature of 140 degrees C. After systematic studies, this excellent catalytic activity was proved to be mainly ascribed to the synergistic effect of Lewis-acidic sites (Zr4+) and Lewis-basic sites (O2- and N) with higher strengths and contents. Meanwhile, Zr-DTPA could be readily separated by filtration, when it was repeatedly used 5 recycles, its catalytic activity was not obviously changed, demonstrating that Zr-DTPA had good heterogeneity and reusability. More importantly, Zr-DTPA could also be employed to effectively catalyze the CTH of 5-methylfurfural, furfural, levulinic acid, ethyl levulinate and cyclohexanone into the corresponding products with high yields, indicating that it showed a superior universality for the selective hydrogenation of various biomass-derived carbonyl compounds.Graphical Abstract

HPLC of Formula: C5H4N2O2. Welcome to talk about 98-97-5, If you have any questions, you can contact Hu, L; Liu, S; Song, J; Jiang, YT; He, AY; Xu, JX or send Email.

Reference:
Patent; Chevron Research Company; US4732894; (1988); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

An article Zirconium-Containing Organic-Inorganic Nanohybrid as a Highly Efficient Catalyst for the Selective Synthesis of Biomass-Derived 2,5-Dihydroxymethylfuran in Isopropanol WOS:000538735600030 published article about TRANSFER HYDROGENATION; LEVULINIC ACID; ELECTROCATALYTIC HYDROGENATION; REDUCTIVE ETHERIFICATION; FURFURYL ALCOHOL; CONVERSION; TRANSFORMATION; HMF; 2,5-BIS(HYDROXYMETHYL)FURAN; DERIVATIVES in [Hu, Lei; Liu, Su; Song, Jie; Jiang, Yetao; He, Aiyong; Xu, Jiaxing] Huaiyin Normal Univ, Jiangsu Collaborat Innovat Ctr Reg Modern Agr & E, Sch Chem & Chem Engn, Jiangsu Key Lab Biomass Based Energy & Enzyme Tec, Huaian 223300, Peoples R China in 2020, Cited 82. The Name is Pyrazine-2-carboxylic acid. Through research, I have a further understanding and discovery of 98-97-5. Name: Pyrazine-2-carboxylic acid

By the simple assembly of zirconium tetrachloride and diethylenetriaminepentaacetic acid (DTPA), a new acid-base bifunctional zirconium-containing organic-inorganic nanohybrid catalyst (Zr-DTPA) was successfully prepared in this work, and then used for the catalytic transfer hydrogenation (CTH) of biomass-derived 5-hydroxymethylfurfural (HMF) into 2,5-dihydroxymethylfuran (DHMF) using isopropanol as the in situ hydrogen donor and reaction solvent. Satisfactorily, 98.7% HMF conversion and 95.2% DHMF yield could be achieved in 4 h at a moderate reaction temperature of 140 degrees C. After systematic studies, this excellent catalytic activity was proved to be mainly ascribed to the synergistic effect of Lewis-acidic sites (Zr4+) and Lewis-basic sites (O2- and N) with higher strengths and contents. Meanwhile, Zr-DTPA could be readily separated by filtration, when it was repeatedly used 5 recycles, its catalytic activity was not obviously changed, demonstrating that Zr-DTPA had good heterogeneity and reusability. More importantly, Zr-DTPA could also be employed to effectively catalyze the CTH of 5-methylfurfural, furfural, levulinic acid, ethyl levulinate and cyclohexanone into the corresponding products with high yields, indicating that it showed a superior universality for the selective hydrogenation of various biomass-derived carbonyl compounds.Graphical Abstract

Bye, fridends, I hope you can learn more about C5H4N2O2, If you have any questions, you can browse other blog as well. See you lster.. Name: Pyrazine-2-carboxylic acid

Reference:
Patent; Chevron Research Company; US4732894; (1988); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

An article Controllable luminescent behaviors with pyrazine and benzimidazole groups: Syntheses, crystal structures and properties WOS:000505108100018 published article about BIOLOGICAL EVALUATION; ORGANIC FRAMEWORKS; COMPLEXES; ANTICANCER; POLYMERS; DERIVATIVES; COPPER; DRUGS; PHOTOLUMINESCENCE; HETEROCYCLES in [Wang, Yong-Tao; Wu, Yu-Song; Tang, Gui-Mei] Qilu Univ Technol, Shandong Acad Sci, Dept Chem Engn, Jinan 250353, Shandong, Peoples R China in 2019, Cited 103. HPLC of Formula: C5H4N2O2. The Name is Pyrazine-2-carboxylic acid. Through research, I have a further understanding and discovery of 98-97-5

A set of new salts containing benzimidazole and pyrazine groups, namely, [HPZBI]X-+(-) nH(2)O (X = Cl (n = 1) (1), NO3 (n = 1) (2), ClO4 (n = 0) (3) and H2PO4 (n = 0) (4)) [PZBI = 2-(pyrazin-2-yl)-1H-benzimidazole], were obtained by the reaction of PZBI and a set of inorganic acid, respectively. The emission maxima can be found at 444, 472, 471, 432 and 443 nm for PZBI and its compounds 1-4 in the solid state at room temperature, respectively. Compared with the free PZBI, the emission maxima of compounds 1-4 are obviously blue/red-shifted for 1-4, indicating that the emission maxima are relative to the intermolecular packing distances. Their photoluminescent lifetime and quantum yield are 1.10 ns and 24.5% for 1, 0.99 ns and 26.4% for 2, 0.94 ns and 21.65% for 3, 2.86 ns and 20.57% for 4, respectively. Compounds 1-4 were structurally characterized by X-ray single crystal diffraction, FT-IR, and UV-Vis spectra. Single crystal X-ray diffraction reveals that pi center dot center dot center dot pi packing interactions and a set of hydrogen bonds can be observed. The shortest distances of pi center dot center dot center dot pi stacking interactions are 3.613, 3.534, 3.731 and 3.492 angstrom in compounds 1-4, respectively. Additionally, the thermal stabilities of compounds 1-4 were investigated in detail.

Welcome to talk about 98-97-5, If you have any questions, you can contact Wang, YT; Wu, YS; Tang, GM or send Email.. HPLC of Formula: C5H4N2O2

Reference:
Patent; Chevron Research Company; US4732894; (1988); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Authors Alcantara, R; Fuentes, P; Antiparra, R; Santos, M; Gilman, RH; Kirwan, DE; Zimic, M; Sheen, P in AMER SOC MICROBIOLOGY published article about PNCA MUTATIONS; PYRAZINOIC ACID; MGIT 960; PREVALENCE; EFFLUX; TESTS in [Alcantara, Roberto; Fuentes, Patricia; Antiparra, Ricardo; Santos, Marco; Zimic, Mirko; Sheen, Patricia] Univ Peruana Cayetano Heredia, Lab Bioinformat & Biol Mol, Fac Ciencias & Filosofia, Lima, Peru; [Gilman, Robert H.] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Int Hlth, Baltimore, MD USA; [Kirwan, Daniela E.] St Georges Univ London, Inst Infect & Immun, London, England in 2019, Cited 45. Name: Pyrazine-2-carboxylic acid. The Name is Pyrazine-2-carboxylic acid. Through research, I have a further understanding and discovery of 98-97-5

Although pyrazinamide (PZA) is a key component of first- and second-line tuberculosis treatment regimens, there is no gold standard to determine PZA resistance. Approximately 50% of multidrug-resistant tuberculosis (MDR-TB) and over 90% of extensively drug-resistant tuberculosis (XDR-TB) strains are also PZA resistant. pncA sequencing is the endorsed test to evaluate PZA susceptibility. However, molecular methods have limitations for their wide application. In this study, we standardized and evaluated a new method, MODS-Wayne, to determine PZA resistance. MODS-Wayne is based on the detection of pyrazinoic acid, the hydrolysis product of PZA, directly in the supernatant of sputum cultures by detecting a color change following the addition of 10% ferrous ammonium sulfate. Using a PZA concentration of 800 mu g/ml, sensitivity and specificity were evaluated at three different periods of incubation (reading 1, reading 2, and reading 3) using a composite reference standard (MGIT-PZA, pncA sequencing, and the classic Wayne test). MODS-Wayne was able to detect PZA resistance, with a sensitivity and specificity of 92.7% and 99.3%, respectively, at reading 3. MODS-Wayne had an agreement of 93.8% and a kappa index of 0.79 compared to the classic Wayne test, an agreement of 95.3% and kappa index of 0.86 compared to MGIT-PZA, and an agreement of 96.9% and kappa index of 0.90 compared to pncA sequencing. In conclusion, MODS-Wayne is a simple, fast, accurate, and inexpensive approach to detect PZA resistance, making this an attractive assay especially for low-resource countries, where TB is a major public health problem.

Bye, fridends, I hope you can learn more about C5H4N2O2, If you have any questions, you can browse other blog as well. See you lster.. Name: Pyrazine-2-carboxylic acid

Reference:
Patent; Chevron Research Company; US4732894; (1988); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem

Safety of Pyrazine-2-carboxylic acid. In 2019 DALTON T published article about AQUEOUS-SOLUTION; EQUILIBRIUM-CONSTANTS; CARBOXYLIC-ACIDS; URANIUM(VI); CRYSTAL; ION; CHEMISTRY; LIGAND in [Lv, Lina; Chen, Baihua; Liu, Jun; Yang, Yanqiu] China Acad Engn Phys, Inst Nucl Phys & Chem, Mianyang 621900, Sichuan, Peoples R China; [Chen, Jing; Xu, Chao] Tsinghua Univ, Inst Nucl & New Energy Technol, Beijing 100084, Peoples R China in 2019, Cited 42. The Name is Pyrazine-2-carboxylic acid. Through research, I have a further understanding and discovery of 98-97-5.

Complexation of U(vi) with pyridazine-3-carboxylate (PDZ) and pyrazine-2-carboxylate (PAZ) was studied by spectrophotometry, potentiometry and microcalorimetry in 1.0 mol dm(-3) NaClO4. Three complexes, [UO2L](+), UO2L2(aq) and [UO2L3](-), were identified and their stability constants (log) and the corresponding formation enthalpies were determined. The thermodynamic parameters indicate that the formation of the three complexes is endothermic and driven exclusively by entropy. H-1 and C-13-NMR data provide insight into the coordination modes of the complexes which corroborate with the thermodynamic data. Ligands chelate to U(vi) via (2)(N,O) coordination mode in complexes [UO2L](+) and UO2L2(aq). The crystal structures of four U(vi) complexes, [(UO2)(PAZ)(2)(H2O)]H2O(i), [(UO2)(PDZ)(2)(H2O)](ii), [(UO2)(PDZ)(3)Na2ClO4]2H(2)O(iii), and [(UO2)(2)(PDZ)(4)(H2O)(2)]2H(2)O(iv), were determined by single-crystal X-ray diffraction and compared with the U(vi) complex with picolinate (PA) (CH6N3)[UO2(PA)(3)] in the literature. The structure data suggest that the carboxylates coordinate with uranium in O?C-O-U mode. The strengths of the U-O-C-C-N chelate cycles in the U(vi)/L complexes decrease with the trend of PA > PDZ > PAZ, which is in great agreement with the trend of thermodynamic parameters in aqueous solutions. It is interesting that in compound II two PDZ molecules coordinate with U(vi) in cis-planar positions via (2)(N,O) mode, but in other metal complexes of the three ligands having the same (2)(N,O) coordination mode the two ligand molecules are all in trans-arrangement. In the dimeric complex IV, one ligand coordinate with U(vi) in (2)(N,O) mode, while the other does it in (2)-L-(2)(O:O) mode respectively.

Safety of Pyrazine-2-carboxylic acid. Bye, fridends, I hope you can learn more about C5H4N2O2, If you have any questions, you can browse other blog as well. See you lster.

Reference:
Patent; Chevron Research Company; US4732894; (1988); A;,
Pyrazine – Wikipedia,
Pyrazine | C4H4N2 – PubChem