Heterocyclic Building Blocks-quinoxaline

Heilporn, Sylvie; Kaisin, Michel; Flammang, Robert published the artcile< Study of the mass spectral fragmentation processes in dinitroquinoxalines using tandem methodologies>, Product Details of C8H4ClN3O2, the main research area is dinitro quinoxaline mass spectra fragmentation mechanism.

The fragmentations of 11 isomeric dinitroquinoxalines following electron ionization were studied, making use of tandem mass-spectrometry methodologies such as collisional activation (CA), various linked-scanning (LS) experiments, and mass-analyzed ion-kinetic-energy (MIKE) spectrometry. For 5,6- (I) and 6,7-dinitroquinoxaline (II), the most abundant fragment ion at m/z 116 is generated for II by successive losses of NO2·, CO, and NO·, whereas for I it is the result of 2 main competing fragmentation routes. 5,7-Dinitroquinoxaline fragmentation differs significantly, as an abundant and quite characteristic ion at m/z 127 results from consecutive eliminations of NO2· and HNO2. Addnl. substitution of the pyrazine or the benzene ring strongly modifies the reactivity.

European Mass Spectrometry published new progress about Fragmentation reaction. 6272-25-9 belongs to class quinoxaline, and the molecular formula is C8H4ClN3O2, Product Details of C8H4ClN3O2.

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Caronna, T.; Gambarotti, C.; Palmisano, L.; Punta, C.; Recupero, F. published the artcile< Sunlight induced functionalization of some heterocyclic bases in the presence of polycrystalline TiO2>, Recommanded Product: Quinoxaline-2-carboxamide, the main research area is quinoline sunlight functionalization titanium oxide; photochem oxidation sunlight functionalization titanium oxide; quinoxaline sunlight functionalization titanium oxide; quinaldine methylquinoline sunlight functionalization titanium oxide; lepidine methylquinoline sunlight functionalization titanium oxide.

The functionalization of various heterocyclic bases induced by sunlight is reported. The photoreaction occurred with higher yield in a liquid-solid heterogeneous system in the presence of polycrystalline TiO2 (anatase) than in a homogeneous system under the same exptl. conditions.

Chemical Communications (Cambridge, United Kingdom) published new progress about Amidation. 5182-90-1 belongs to class quinoxaline, and the molecular formula is C9H7N3O, Recommanded Product: Quinoxaline-2-carboxamide.

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Aoki, Katsuyuki; Obata, Tatsuhiro; Yamazaki, Yosuke; Mori, Yoshikazu; Hirokawa, Hiroko; Koseki, Jun-ichi; Hattori, Tomohisa; Niitsu, Kazuaki; Takeda, Shuichi; Aburada, Masaki; Miyamoto, Ken-ichi published the artcile< Potent platelet-derived growth factor-β receptor (PDGF-βR) inhibitors: synthesis and structure-activity relationships of 7-[3-(cyclohexylmethyl)ureido]-3-{1-methyl-1H-pyrrolo[2,3-b]pyridin-3-yl}quinoxalin-2(1H)-one derivatives>, Category: quinoxaline, the main research area is pyrrolopyridinylquinoxalinone preparation platelet derived growth factor receptor inhibitor.

The authors found previously that 7-[3-(cyclohexylmethyl)ureido]-3-{1-methyl-1H-pyrrolo[2,3-b]pyridin-3-yl}quinoxalin-2(1H)-one has considerable potency as a PDGF inhibitor. This compound showed potent inhibitory activity in a PDGF-induced CPA (Cell Proliferation Assay) and APA (Auto-Phosphorylation Assay) (IC50 = 0.05 μmol/l in CPA, 0.03 μmol/l in APA). Therefore, the authors tried to develop a novel and effective PDGF-βR inhibitor by optimizing a series of its derivatives The authors found that trifluoroacetic acid (TFA)-catalyzed coupling of pyrrolo[2,3-b]pyridines with quinoxalin-2-ones proceeded efficiently under mild oxidation condition with manganese(IV) oxide (MnO2) in situ, so this method was applied to prepare a series of derivatives Results of in vitro screening of newly synthesized derivatives identified compound I (R = pentyl) as having potent (IC50 = 0.014 μmol/l in CPA, 0.007 μmol/l in APA) and selective [IC50 values against vascular endothelial growth factor receptor 2 (VEGFR2, kinase domain region, KDR), epidermal growth factor receptor (EGFR), c-Met (hepatocyte growth factor receptor) and insulin growth factor I receptor (IGF-IR)/IC50 against PDGFR were each >1000] inhibitory activity. Moreover, in this series of derivatives, 7-[3-(cyclohexylmethyl)thioureido]-3-(1-methyl-1H-pyrrolo[2,3-b]pyridin-3-yl)quinoxalin-2(1H)-one showed potent inhibitory activity toward both PDGF- and VEGF-induced signaling (PDGFR: IC50 = 0.004 μmol/l in CPA, 0.0008 μmol/l in APA, KDR: IC50 = 0.008 μmol/l in APA). Herein, the authors report a new and convenient synthetic method for this series of derivatives and its SAR study.

Chemical & Pharmaceutical Bulletin published new progress about Platelet-derived growth factor receptor β Role: BSU (Biological Study, Unclassified), BIOL (Biological Study). 89898-96-4 belongs to class quinoxaline, and the molecular formula is C8H5N3O3, Category: quinoxaline.

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Li, Yi-Na; Li, Xue-Lin; Wu, Jin-Bo; Jiang, Hong; Liu, Yunmei; Guo, Yu; Zeng, Yao-Fu; Wang, Zhen published the artcile< Metal-free regioselective nitration of quinoxalin-2(1H)-ones with tert-butyl nitrite>, Reference of 89898-96-4, the main research area is nitro quinoxalinone preparation regioselective; quinoxalinone tert butyl nitrite metal free nitration.

A metal-free coupling of quinoxalin-2(1H)-ones with tert-Bu nitrite has been developed. Distinctly from the previous functionalization of quinoxalin-2(1H)-ones, this nitration reaction took place selectively at the C7 or C5 position of the Ph ring, affording a series of 7-nitro and 5-nitro quinoxalin-2(1H)-ones in moderate to good yields. Preliminary mechanistic studies revealed that the reaction may involve a radical process.

Organic & Biomolecular Chemistry published new progress about Coupling reaction, regioselective. 89898-96-4 belongs to class quinoxaline, and the molecular formula is C8H5N3O3, Reference of 89898-96-4.

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Deng, Jing; Feng, Enguang; Ma, Sheng; Zhang, Yan; Liu, Xiaofeng; Li, Honglin; Huang, Huang; Zhu, Jin; Zhu, Weiliang; Shen, Xu; Miao, Liyan; Liu, Hong; Jiang, Hualiang; Li, Jian published the artcile< Design and synthesis of small molecule RhoA inhibitors: a new promising therapy for cardiovascular diseases?>, Related Products of 89898-96-4, the main research area is quinoxaline derivative preparation SAR drug screen RhoA inhibitory; cardiovascular disease.

RhoA is a member of Rho GTPases, a subgroup of the Ras superfamily of small GTP-binding proteins. RhoA, as an important regulator of diverse cellular signaling pathways, plays significant roles in cytoskeletal organization, transcription, and cell-cycle progression. The RhoA/ROCK inhibitors have emerged as a new promising treatment for cardiovascular diseases. However, to date, RhoA inhibitors are macromols., and to our knowledge, small mol.-based inhibitors have not been reported. In this study, a series of first-in-class small mol. RhoA inhibitors have been discovered by using structure-based virtual screening in conjunction with chem. synthesis and bioassay. Virtual screening of ∼200,000 compounds, followed by SPR-based binding affinity assays resulted in three compounds with binding affinities to RhoA at the micromolar level. Compound I was selected for further structure modifications in considering binding activity and synthesis ease. Forty-one new compounds were designed and synthesized accordingly. It was found that eight showed high RhoA inhibition activities with IC50 values of 1.24 to 3.00 μM. A pharmacol. assay indicated that two compounds II and III demonstrated noticeable vasorelaxation effects against PE-induced contraction in thoracic aorta artery rings and served as good leads for developing more potent cardiovascular agents.

Journal of Medicinal Chemistry published new progress about Amination. 89898-96-4 belongs to class quinoxaline, and the molecular formula is C8H5N3O3, Related Products of 89898-96-4.

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Rustenburg, Arien S.; Dancer, Justin; Lin, Baiwei; Feng, Jianwen A.; Ortwine, Daniel F.; Mobley, David L.; Chodera, John D. published the artcile< Measuring experimental cyclohexane-water distribution coefficients for the SAMPL5 challenge>, Electric Literature of 5182-90-1, the main research area is cyclohexane water SAMPL5 analysis; Blind challenge; Distribution coefficients; Partition coefficients; Predictive modeling; SAMPL.

Small mol. distribution coefficients between immiscible nonaqueuous and aqueous phases-such as cyclohexane and water-measure the degree to which small mols. prefer one phase over another at a given pH. As distribution coefficients capture both thermodn. effects (the free energy of transfer between phases) and chem. effects (protonation state and tautomer effects in aqueous solution), they provide an exacting test of the thermodn. and chem. accuracy of phys. models without the long correlation times inherent to the prediction of more complex properties of relevance to drug discovery, such as protein-ligand binding affinities. For the SAMPL5 challenge, we carried out a blind prediction exercise in which participants were tasked with the prediction of distribution coefficients to assess its potential as a new route for the evaluation and systematic improvement of predictive phys. models. These measurements are typically performed for octanol-water, but we opted to utilize cyclohexane for the nonpolar phase. Cyclohexane was suggested to avoid issues with the high water content and persistent heterogeneous structure of water-saturated octanol phases, since it has greatly reduced water content and a homogeneous liquid structure. Using a modified shake-flask LC-MS/MS protocol, we collected cyclohexane/water distribution coefficients for a set of 53 druglike compounds at pH 7.4. These measurements were used as the basis for the SAMPL5 Distribution Coefficient Challenge, where 18 research groups predicted these measurements before the exptl. values reported here were released. In this work, we describe the exptl. protocol we utilized for measurement of cyclohexane-water distribution coefficients, report the measured data, propose a new bootstrap-based data anal. procedure to incorporate multiple sources of exptl. error, and provide insights to help guide future iterations of this valuable exercise in predictive modeling.

Journal of Computer-Aided Molecular Design published new progress about pH. 5182-90-1 belongs to class quinoxaline, and the molecular formula is C9H7N3O, Electric Literature of 5182-90-1.

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Citterio, Attilio; Gentile, Anna; Minisci, Francesco; Serravalle, Marco; Ventura, Susanna published the artcile< Polar effects in free-radical reactions. Carbamoylation and α-N-amidoalkylation of heteroaromatic bases by amides and hydroxylamine-O-sulfonic acid>, Electric Literature of 5182-90-1, the main research area is heterocycle carbamoylation amidoalkylation mechanism.

NH3+·, formed in the decomposition of H3N+OSO3- by Fe2+, generates carbamoyl and α-N-amidoalkyl radicals by H abstraction from formamide, alkylformamides, and N-alkylacetamides. Both carbamoyl and α-N-amidoalkyl radicals have a clear-cut nucleophilic character and selectively attack protonated heteroaromatic bases, e.g., 4-methylquinoline or quinoxaline, in the α-position or are oxidized by Fe(III) salts. Redox chain mechanisms are involved. The importance of the polar effects in the H abstraction, aromatic substitution, and oxidation by Fe(III) salt is discussed.

Journal of Organic Chemistry published new progress about Amidoalkylation. 5182-90-1 belongs to class quinoxaline, and the molecular formula is C9H7N3O, Electric Literature of 5182-90-1.

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Nasielski-Hinkens, R.; Vande Vyver, E.; Nasielski, J. published the artcile< Regioselectivity in the reaction of nitroquinoxaline N-oxides with phosphoryl chloride>, COA of Formula: C8H4ClN3O2, the main research area is nitroquinoxaline oxide phosphoryl chloride regiochem; chloroquinoxaline; quinoxaline chloro; Meisenheimer nitroquinoxaline oxide regiochem.

Oxidation of nitroquinoxalines I (n = 0; R, R1 = H, Me) by m-ClC6H4CO2OH gave their N-oxides; the NO2 group orients the O atom preferentially to N-1, but the N-4:N-1 selectivity is diminished in the methylated derivatives Meisenheimer reaction of I (n = 1, R = R1 = H) with POCl3 gave I (n = 0, R = Cl, R1 = H). The orientation of the entering Cl is discussed on the basis of electronic effects induced by the N-oxide and NO2 groups.

Bulletin des Societes Chimiques Belges published new progress about Regiochemistry. 6272-25-9 belongs to class quinoxaline, and the molecular formula is C8H4ClN3O2, COA of Formula: C8H4ClN3O2.

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Minisci, Francesco; Gardini, G. P.; Galli, Remo; Bertini, F. published the artcile< New selective type of aromatic substitution: homolytic amidation>, SDS of cas: 5182-90-1, the main research area is heterocycle nitrogen homolytic amidation; homolytic amidation nitrogen heterocycle; amidation homolytic nitrogen heterocycle; nitrogen heterocycle homolytic amidation; heterocycle nitrogen homolytic amidation; carbamoylation homolytic nitrogen heterocycle; carbamoyl pyridines pyrazines; pyridines carbamoyl pyrazines; pyrazines carbamoyl pyridines; thiazoles imidazoles benzimidazoles amidation; imidazoles benzimidazoles thiazoles amidation; benzimidazoles imidazoles thiazoles amidation; carbamoyl radical nucleophilic character.

I, II (at least one of R1 and R2 is CONH2), and III are prepared by carbamoylation. Thus, 34% H2O2 soin. is added to quinoxaline and concentrated H2SO4 in HCONH2 at 10-15°. FeSO4.7H2O is added simultaneously, to give 97% 2-quinoxalinecarboxamide. Similarly prepared are I (R = H) and the following II (R, R1, and R2 given): H, CONH2, CONH2; H, CONH2, Et; (RR =)CH:CHCH:CH, CONH2, CONH2; (RR =) CH:CHCH:CH, CONH2, Me; (RR =) CH:CHCH:CH, Me, CONH2. Also prepared were 1-carbamoyl-isoquinoline, III (R = S), and III (R = NH).

Tetrahedron Letters published new progress about 5182-90-1. 5182-90-1 belongs to class quinoxaline, and the molecular formula is C9H7N3O, SDS of cas: 5182-90-1.

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Liu, Luo-Yan; Qiao, Jennifer X.; Yeung, Kap-Sun; Ewing, William R.; Yu, Jin-Quan published the artcile< meta C-H Arylation of Electron-Rich Arenes: Reversing the Conventional Site Selectivity>, Computed Properties of 23088-24-6, the main research area is meta arylation electron rich arene mutually repulsive pyridine ligand; reverse site selectivity alkoxy aromatic compound arylation.

Controlling site selectivity of C-H activation without using a directing group remains a significant challenge. While Pd(II) catalysts modulated by a mutually repulsive pyridine-type ligand have been shown to favor the relatively electron-rich carbon centers of arenes, reversing the selectivity to favor palladation at the relatively electron-deficient positions has not been possible. Herein we report the first catalytic system that effectively performs meta C-H arylation of a variety of alkoxy aromatics including 2,3-dihydrobenzofuran and chroman with exclusive meta site selectivity, thus reversing the conventional site selectivity governed by native electronic effects. The identification of an effective ligand and modified norbornene (NBE-CO2Me), as well as taking advantage of the statistics, are essential for achieving the exclusive meta selectivity.

Journal of the American Chemical Society published new progress about Aromatic ethers Role: RCT (Reactant), SPN (Synthetic Preparation), RACT (Reactant or Reagent), PREP (Preparation). 23088-24-6 belongs to class quinoxaline, and the molecular formula is C9H5N3, Computed Properties of 23088-24-6.

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider