1196-57-2Relevant articles and documents
Iodine-Catalyzed Oxidative Cross-Dehydrogenative Coupling of Quinoxalinones and Indoles: Synthesis of 3-(Indol-2-yl)quinoxalin-2-one under Mild and Ambient Conditions
Noikham, Medena,Kittikool, Tanakorn,Yotphan, Sirilata
, p. 2337 - 2346 (2018)
A highly efficient iodine-catalyzed oxidative cross-dehydrogenative coupling reaction of quinoxalinones and indoles has been developed. Without the requirement of peroxide and acid, this reaction utilizes a catalytic amount of molecular iodine to facilitate the C-C bond formation under ambient air. This simple and easy-to-handle protocol represents an interesting synthetic alternative with a good scope and functional group compatibility.
Synthesis of 2-(4-nitrophenoxy)quinoxaline and its reactions with hydroxide ion in micellar systems
Cuenca, Angela,Bruno, Cesidio,Taddei, Antonieta
, p. 1927 - 1934 (1991)
The synthesis of 2-(4-nitrophenoxy)quinoxaline (3) is described. The reaction of (3) with hydroxide ion was studied in the presence and absence of micellar systems. Cationic micelles of cetyltrimethylammonium chloride and bromide (CTACl and CTABr) and tetradecyltrimethylammonium chloride and bromide (MTACl and MTABr) speed the reaction of (3) with hydroxide ion. The second-order rate constants at the micellar pseudophase are smaller than the second-order rate constant in water.
Chemoselective synthesis of 3,6,7-trisubstituted 2-(2,3:5,6-di-O-isopropylidene-β-D-mannofuranosyloxy]- and 2-(2-acetamido-3,4,6-tri-O-acetyl-2-deoxy-β-D-glucopyranosyloxy)quinoxaline derivatives
Fathalla, Walid
, p. 67 - 72 (2015)
[Figure not available: see fulltext.] A series of quinoxaline O-nucleosides, 3,6,7-trisubstituted 2-(2,3:5,6-di-O-isopropylidene-β-D-mannofuranosyl-1-yl)quinoxalines and 2-(2-acetamido-2-deoxy-3,4,6-tri-O-acetyl-β-D-glucopyranosyl)quinoxalines, was prepared by the reaction of 3,6,7-trisubstituted quinoxalin-2(1H)-ones with the corresponding protected α-chlorosugars in the presence of NaH. The reaction proceeded chemoselectively to give products of O-substitution with β-configuration at anomeric carbon, as proved by NMR data. The deprotection of the 1-(2-acetamido-2-deoxy-3,4,6-tri-O-acetyl-β-D-glucopyranosyl)quinoxalines was achieved by stirring in ammonia-methanol mixture to afford free O-quinoxaline nucleoside analogs.
Electrochemically C-H/S-H Oxidative Cross-Coupling between Quinoxalin-2(1 H)-ones and Thiols for the Synthesis of 3-Thioquinoxalinones
Zhou, Jiadi,Li, Zhonghui,Sun, Zexu,Ren, Quanlei,Zhang, Qiwei,Li, Hu,Li, Jianjun
, p. 4365 - 4372 (2020)
An electrochemical method for the C(sp2)-H thioetherification of quinoxalin-2(1H)-ones with primary, secondary, and tertiary thiols has been reported. Various quinoxalin-2(1H)-ones underwent this thioetherification smoothly under metal- A nd chemical oxidant-free conditions, affording 3-alkylthiol-substituted quinoxalin-2(1H)-ones in moderate to good yields.
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Taylor,Thompson
, p. 3511 (1961)
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UNPRODUCTIVE SIGMA AND PI COMPLEXES IN THE REACTION OF 2-CHLOROQUINOXALINE WITH PIPERIDINE IN DIMETHYL SULPHOXIDE
Nasielski, J.,Rypens, C.
, p. 545 - 550 (1994)
The rate of the reaction of 2-chloroquinoxaline with piperidine in dimethyl sulphoxide was measured over a wide range of amine concentrations and at several temperatures.It was found that the order with respect to the nucleophile is close to 1 between 300 and 320 K, but is definitely less at lower and higher temperatures.It is suggested that below 300 K an unreactive charge-transfer complex is formed between the reactants which dissociates at higher temperatures, whereas at temperatures higher than 320 K an unproductive ? complex is formed, the concentration of which increases with increase in temperature.
Rapidly formed quinalphos complexes with transition metal ions characterized by electrospray ionization mass spectrometry
Keller, Bernd O.,Esbata, Abdelhamid A.,Buncel, Erwin,Van Loon, Gary W.
, p. 1319 - 1328 (2013)
RATIONALE Electrospray ionization tandem mass spectrometry (ESI-MS/MS) offers the unique opportunity to characterize complexes of the organophosphorus pesticide (OP) quinalphos (PA-Q) with transition metal ions immediately formed after contact. This study complements research looking at longer term kinetics of quinalphos hydrolysis in the presence of transition metal ions and gives insights into the structural features of the initial complex formation in solution. (Hydrolysis reaction: PA-Q + H2O → PA-OH + HQ, where PA-OH is the diethyl phosphate product and HQ is hydroxyquinoxaline.) METHODS Low micromolar PA-Q solutions with an approximately 3-fold molar excess of transition metal ions were immediately analyzed after mixing. Fragmentation of the transition metal ion complexes with PA-Q was accomplished in two different ways: first, in-source fragmentation by elevating the declustering potential and second, low-energy collision-induced dissociation (CID). RESULTS For Ag +, the [PA-Q - Ag+] and respective Ag+- containing degradation product ions are readily observed. For Cu2+, we observed the [PA-Q + Cu2+ + NO3-] complex ion with weak intensity and strong signals from both the [2PA-Q + Cu +] and the [PA-Q + Cu+] ions, the latter two attributable to charge-state reduction in the gas phase from Cu(II) to Cu(I), indicating that PA-Q fulfills specific structural requirements of the formed complex for charge-state reduction during transition from solution to the gas phase. For Hg2+, the [PA-Q + Hg2+ + (PA-OH - H)-] ion was the largest observed species containing one Hg2+ ion. No 1:1 species ([PA-Q] or other degradation products:Hg2+) was observable. CONCLUSIONS ESI-MS/MS of complexes formed from PA-Q and transition metal ions is a formidable technique to probe initial formation of these complexes in solution. Previous work from other groups established structural requirements that enable charge-state reduction from Cu(II) to Cu(I) in ligand complexes during transition into the gas phase, and these rules allow us to propose structural features of PA-Q complexes with copper ions in solution. Copyright 2013 John Wiley & Sons, Ltd. Copyright
Kinetics of solvolysis of 2-chloroquinoxaline
Patel
, p. 403 - 406 (1994)
Pseudo-first-order rate constants and activation parameters have been measured for the solvolysis of 2-chloroquinoxaline in various aquo-organic mixtures using methanol, ethanol, and isopropanol as the organic solvent. Excellent linear correlations are found between lnk and the mol fraction of cosolvent and In[H2O]. The medium effect on the rates of solvolysis is assessed by Grunwald-Winstein's mY correlationship. the estimated values of m (0.55-0.72) and the entropy of activation (148-212 J deg-1 mol-1) for the reactions are well in the range for a bimolecular aromatic substitution reactions.
Synthesis and X-ray structures of unexpected 2-O-(5-deoxy-1,2-O- isopropylidene-α-D-glucofuranos-5-yloxy)quinoxalines
Jarmoumi, Chakir,Lakhrissi, Brahim,Mondieig, Denise,Negrier, Philippe,Leger,Massip,Lazard, Zhor,Benali, Bouziane,Massoui, Mohamed,Essassi, El Mokhtar
, p. 585 - 592 (2009)
Reaction of 3-methyl-2(1H)-quinoxalinone (4) and 2(1H)-quinoxalinone (5) with 5,6-anhydro-1,2-O-isopropylidene-α-D-glucofuranose 6 gives the unexpected O-glucoquinoxalines derivatives by the intermediary novel intramolecular rearrangement of 5,6-anhydro-1,2-O-isopropylidene-α-D- glucofuranose to the corresponding 3,6-anhydro form. The obtained O-glucoquinoxalines 7,8 were identified by NMR spectroscopy. The X-ray crystal structures have been determined at room temperature. Moreover, a solid-solid phase transition has been detected at 198.9 K for O-glucoquinoxalines 7 and the structure of the low-temperature phase has been solved at 188K.
Dibenzothiophene Catabolism Proceeds via a Flavin-N5-oxide Intermediate
Adak, Sanjoy,Begley, Tadhg P.
, p. 6424 - 6426 (2016)
The dibenzothiophene catabolic pathway converts dibenzothiophene to 2-hydroxybiphenyl and sulfite. The third step of the pathway, involving the conversion of dibenzothiophene sulfone to 2-(2-hydroxyphenyl)-benzenesulfinic acid, is catalyzed by a unique flavoenzyme DszA. Mechanistic studies on this reaction suggest that the C2 hydroperoxide of dibenzothiophene sulfone reacts with flavin to form a flavin-N5-oxide. The intermediacy of the flavin-N5-oxide was confirmed by LC-MS analysis, a co-elution experiment with chemically synthesized FMN-N5-oxide and 18O2 labeling studies.
Micellar effects upon the alkaline hydrolysis of 2-(3-nitrophenoxy)quinoxaline. Effects of cationic head groups
Cuenca, Angela
, p. 12361 - 12368 (1997)
The rate of alkaline hydrolysis of the novel compound 2-(3-nitrophenoxy)quinoxaline 1 increases with increasing head group size in a series of cationic micellized surfactants (C16H33NR3Cl and C16H33NR3OH: R = Me, Et, n-Pr and n-Bu). The reactivity increase with increasing head group size is related to the disruption of the hydration of hydroxide ion.
Persulfate-promoted oxidative C-N bond coupling of quinoxalinones and: NH -sulfoximines
Sumunnee, Ladawan,Pimpasri, Chaleena,Noikham, Medena,Yotphan, Sirilata
, p. 2697 - 2704 (2018)
The persulfate-meditated oxidative C-N bond coupling of the C-H bond of quinoxalinones and the N-H bond of NH-sulfoximines is reported. The reaction proceeds smoothly under transition metal-free conditions and provides good to excellent yields of sulfoximidoyl-functionalized quinoxalinone products under mild conditions. The optimized conditions were found to be suitable for a range of sulfoximine and quinoxalinone substrates. This reaction offers a new and convenient strategy to directly install the sulfoximine moiety into the C3 position of quinoxalinone.
Effect of colloidal self-assemblies on the basic hydrolysis of 2-(4-bromophenoxy)quinoxaline
Cuenca, Angela
, p. 318 - 322 (2003)
In the presence of cationic surfactants (C16H33NR3Cl; R = Me, n-Pr, n-Bu), the shape of rate versus surfactant concentration profiles for the basic hydrolysis of 2-(4-bromophenoxy)quinoxaline depends on substrate concentration. At low substrate concentration there is a single rate maximum and with a 10-fold substrate concentration increase a double rate maximum is observed. The first rate maximum is ascribed to reaction occurring in premicellar aggregates and the second to reaction in micelles. At low substrate concentration the effect of surfactant head group size was examined. Second-order rate constants in the micellar pseudophase increase with increasing head group size. Copyright
Visible-light induced phosphonation of quinoxalines and quinoxalin-2(1H)-ones under aerobic metal-free conditions
Kumar, Rahul,Rawat, Deepa,Subbarayappa, Adimurthy
, p. 6170 - 6175 (2020)
Phosphonation of quinoxalines and quinoxalin-2(1H)-ones utilizing aerobic oxygen as green oxidant under visible light conditions at room temperature has been described. Both quinoxalines and quinoxalin-2(1H)-ones are compatible with alkyl or aryl phosphonates and provided good yields of products through regioselective C-P bond formation under base/ligand-free conditions. Competitive experiments showed quinoxalin-2(1H)-ones are more reactive than quinoxalines under the present conditions, and the control experiments revealed the present transformation proceeds through a radical mechanism.
3-(Nitromethyl)-3,4-dihydroquinoxalin-2(1H)-ones: synthesis and structure
Pelipko, Vasilii V.,Makarenko, Sergey V.,Berestovitskaya, Valentina M.,Baichurin, Ruslan I.
, (2016)
[Figure not available: see fulltext.] Reactions of ethyl 3-nitroacrylate with o-phenylenediamine and its substituted derivatives were used for the synthesis of 3-(nitromethyl)-3,4-dihydroquinoxalin-2(1H)-ones, followed by structural characterization. Thes
PIDA-induced oxidative C–N bond coupling of quinoxalinones and azoles
Wimonsong, Watchara,Yotphan, Sirilata
, (2021)
A metal-free promoted direct oxidative C–N bond coupling of quinoxalinones and azoles for the rapid and effective synthesis of potent pharmaceutical important 3-(azol-1-yl)quinoxalin-2-one has been developed. Employing PIDA as the easily available mediator, the desired coupling products were isolated in moderate to excellent yields with a good substrate scope under operational simplicity and mild reaction conditions. Preliminary mechanistic studies suggested that a radical process is likely to be involved in the reaction.
Synthesis of 2-(2-nitrophenoxy)quinoxaline and its basic hydrolysis in aqueous solutions of non-reactive counter-ion surfactants with bulky head groups
Cuenca, Angela,Strubinger, Adelitza
, p. 11665 - 11672 (1996)
The synthesis of the novel compound 2-(2-nitrophenoxy)quinoxaline (2) is described and its basic hydrolysis was studied in the presence of non-reactive counter-ion surfactants with different head group size. Micellar effects upon the reaction of OH- with (2) were analyzed by using a mass-action-like equation.
A Computer-Driven Scaffold-Hopping Approach Generating New PTP1B Inhibitors from the Pyrrolo[1,2-a]quinoxaline Core
García-Marín, Javier,Griera, Mercedes,Alajarín, Ramón,Rodríguez-Puyol, Manuel,Rodríguez-Puyol, Diego,Vaquero, Juan J.
, p. 2895 - 2906 (2021)
Protein tyrosine phosphatase 1B (PTP1B) is a very promising target for the treatment of metabolic disorders such as type II diabetes mellitus. Although it was validated as a promising target for this disease more than 30 years ago, as yet there is no drug in advanced clinical trials, and its biochemical mechanism and functions are still being studied. In the present study, based on our experience generating PTP1B inhibitors, we have developed and implemented a scaffold-hopping approach to vary the pyrrole ring of the pyrrolo[1,2-a]quinoxaline core, supported by extensive computational techniques aimed to explain the molecular interaction with PTP1B. Using a combination of docking, molecular dynamics and end-point free-energy calculations, we have rationally designed a hypothesis for new PTP1B inhibitors, supporting their recognition mechanism at a molecular level. After the design phase, we were able to easily synthesize proposed candidates and their evaluation against PTP1B was found to be in good concordance with our predictions. Moreover, the best candidates exhibited glucose uptake increments in cellulo model, thus confirming their utility for PTP1B inhibition and validating this approach for inhibitors design and molecules thus obtained.
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Marxer et al.
, p. 2507,2511,2515,2516 (1971)
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Decarboxylative Hydroxylation of Benzoic Acids
Ritter, Tobias,Su, Wanqi,Xu, Peng
, p. 24012 - 24017 (2021/10/06)
Herein, we report the first decarboxylative hydroxylation to synthesize phenols from benzoic acids at 35 °C via photoinduced ligand-to-metal charge transfer (LMCT)-enabled radical decarboxylative carbometalation. The aromatic decarboxylative hydroxylation is synthetically promising due to its mild conditions, broad substrate scope, and late-stage applications.
