Category: quinoxaline

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

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

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

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

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

Senecal, Todd D.; Shu, Wei; Buchwald, Stephen L. published the artcile< A General, Practical Palladium-Catalyzed Cyanation of (Hetero)Aryl Chlorides and Bromides>, Application In Synthesis of 23088-24-6, the main research area is heteroaryl aryl cyanide preparation; palladium catalyst cyanation heteroaryl aryl chloride bromide; cross-coupling; cyanides; heterocycles; homogeneous catalysis; palladium.

The authors have disclosed a general method for the cyanation of (hetero)aryl chlorides and bromides. The authors use a palladium-catalyzed cyanation system that (1) is applicable to aryl chlorides at low to moderate catalyst loadings; (2) works well with a wide range of heterocyclic halides, including in many cases five-membered heterocycles bearing free NH groups; and (3) is complete in one hour at ≤ 100°. The use of a nontoxic cyanide source in conjunction with wide functional-group tolerance and fast reaction times make this method particularly convenient to synthetic chemists.

Angewandte Chemie, International Edition published new progress about Aromatic nitriles Role: SPN (Synthetic Preparation), PREP (Preparation). 23088-24-6 belongs to class quinoxaline, and the molecular formula is C9H5N3, Application In Synthesis of 23088-24-6.

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Wozniak, Marian; Baranski, Andrzej; Nowak, Krystyna; Poradowska, Henryka published the artcile< Regioselectivity of the amination of some nitroquinoxalines by liquid ammonia/potassium permanganate>, SDS of cas: 89898-96-4, the main research area is regioselective amination nitroquinoxaline; quinoxaline nitro regioselective amination.

5- And 6-nitroquinoxalines and some of their derivatives are aminated in a liquid NH3 solution of KMnO4 to yield the corresponding 2- and/or 3- and/or 5-amino compounds Quantum-chem. calculations are made to explain the regioselectivity of the amination reactions.

Liebigs Annalen der Chemie published new progress about Amination, regioselective. 89898-96-4 belongs to class quinoxaline, and the molecular formula is C8H5N3O3, SDS of cas: 89898-96-4.

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Fisher, George H.; Schultz, Harry P. published the artcile< Quinoxaline studies. XXII. Tosylation and chiralities of 2-substituted 1,2,3,4-tetrahydroquinoxalines>, Reference of 5182-90-1, the main research area is tetrahydroquinoxaline tosylation chirality; quinoxaline tetrahydes tosylation chirality.

Tosylation of several 2-R-substituted-1,2,3,4-tetrahydroquinoxalines (I, (R = Me, CH2Oh, CONH2, CO2H, or CO2Et) gave exclusively N-monotosyl derivatives whose NMR spectra justified assignment of the tosyl group of the 1-N position. Support for this assignment was obtained by comparing the NMR spectra of unsubstituted and N-tosylated tetrahydroquinolines and tetrahydroquinaldines as model compounds The tosyl derivatives were then utilized to establish the C-2 chiralities of the various 2-substituted 1,2,3,4-tetrahydroquinoxalines according to the sequence (RS)-1,2,3,4-tetrahydro-2-quinoxalinecarboxamide, (R)-1,2,3,4-tetrahydro-2-quinoxalinecarboxamide, (R)-1-p-tolylsulfonyl-1,2,3,4-tetrahydro-2-quinoxalinecarboxamide, (R)-1-p-tolylsulfonyl-1,2,3,4-tetrahydro-2-quinoxalinecarboxylic acid, (R)-1-p-tolylsulfonyl-1,2,3,4-tetrahydroquinoxaline-2-hydroxymethylquine, and (S)-1-tolylsulfonyl-2-methyl-1,2,3,4-tetrahydroquinoxaline-the latter identical with the configurational standard prepared unequivocally from L-α-alanine.

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

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Long, Xiangdong; Wang, Jia; Gao, Guang; Nie, Chao; Sun, Peng; Xi, Yongjie; Li, Fuwei published the artcile< Direct Oxidative Amination of the Methyl C-H Bond in N-Heterocycles over Metal-Free Mesoporous Carbon>, Category: quinoxaline, the main research area is amide heterocyclic preparation density functional theory kinetic study; heterocycle oxidative amination mesoporous carbon catalyst SAR.

Herein, direct and efficient oxidative amination of the Me C-H bond in a wide range of N-heterocycles such as 2-methylpyridine, 3-methylquinoline, 4-methylpyrimidine, etc. to access the corresponding amides RC(O)NH2 (R = pyridin-2-yl, quinolin-2-yl, 1-methyl-1H-imidazol-2-yl, etc.) over metal-free porous carbon is successfully developed. To understand the fundamental structure-activity relationships of carbon catalysts, the surface functional groups and the graphitization degree of porous carbon have been purposefully tailored through doping with nitrogen or phosphorus. The results of characterization, kinetic studies, liquid-phase adsorption experiments, and theor. calculations indicate that the high activity of the carbon catalyst is attributed to the synergistic effect of surface acidic functional groups (hydroxyl/carboxylic acid/phosphate) and more graphene edge structures exposed on the surface of carbon materials with a high graphitization degree, in which the role of acidic functional groups is to adsorb the substrate mol. and the role of the graphene edge structure is to activate O2.

ACS Catalysis published new progress about Adsorption energy. 5182-90-1 belongs to class quinoxaline, and the molecular formula is C9H7N3O, Category: quinoxaline.

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider

Hazeldine, Stuart T.; Polin, Lisa; Kushner, Juiwanna; Paluch, Jennifer; White, Kathryn; Edelstein, Matthew; Palomino, Eduardo; Corbett, Thomas H.; Horwitz, Jerome P. published the artcile< Design, Synthesis, and Biological Evaluation of Analogues of the Antitumor Agent, 2-{4-[(7-Chloro-2-quinoxalinyl)oxy]phenoxy}propionic Acid (XK469)>, Reference of 6272-25-9, the main research area is chloroquinoxalinyloxyphenoxypropionic acid structure antitumor; quinoxalinyloxyphenoxypropionic acid antitumor preparation.

2-{4-[(7-Chloro-2-quinoxalinyl)oxy]phenoxy}propionic acid (XK469) I is among the most highly and broadly active antitumor agents to have been evaluated and scheduled to enter clin. trials in 2001. The mechanism or mechanisms of action of I remain to be elaborated. Accordingly, an effort was initiated to establish a pharmacophore hypothesis to delineate the requirements of the active site, via a comprehensive program of synthesis of analogs of I and evaluation of the effects of structural modification(s) on solid tumor activity. The strategy formulated chose to dissect the two-dimensional parent structure into three regions: I, ring A of quinoxaline; II, the hydroquinone connector linkage; and III, the lactic acid moiety-to determine the resultant in vitro and in vivo effects of chem. alterations in each region. Neither the A-ring unsubstituted nor the B-ring 3-chloro-regioisomer of I showed antitumor activity. The modulating antitumor effect(s) of substituents of differing electronegativities, located at the several sites comprising the A-ring of region I, were next ascertained. Thus, a halogen substituent, located at the 7-position of a 2-{4-[(2-quinoxalinyl)oxy]phenoxy}propionic acid, generated the most highly and broadly active antitumor agents. A Me, methoxy, or an azido substituent at this site generated a much less active structure, whereas 5-, 6-, 8-chloro-, 6-, 7-nitro, and 7-amino derivatives all proved to be essentially inactive. When the connector linkage (region II) of I was changed from that of a hydroquinone to either a resorcinol or a catechol derivative, all antitumor activity was lost. Of the carboxylic acid derivatives of I (region III), i.e., CONH2, CONHMe, CONMe2, CONHOH, CONHNH2, CN, or CN4H (tetrazole), only the monomethyl- and N,N-dimethylamides proved to be active.

Journal of Medicinal Chemistry published new progress about Antitumor agents. 6272-25-9 belongs to class quinoxaline, and the molecular formula is C8H4ClN3O2, Reference of 6272-25-9.

Referemce:
Quinoxaline – Wikipedia,
Quinoxaline | C8H6N2 | ChemSpider