20595-03-3Relevant academic research and scientific papers
An alternative method to access diverse N,N′-diquaternised-3,3′-biquinoxalinium “biquinoxen” dications
Leblanc, Nicolas,Sproules, Stephen,Powell, Annie K.
, p. 2949 - 2954 (2017)
An alternative synthetic route for the design of N,N′-diquaternised-3,3′-biquinoxalinium “biquinoxen” dications is reported, involving oxidative radical coupling of dithionite reduced quinoxaline quaternary salts. Although the reaction is not regioselective, leading to relatively modest yields (up to 32%), the advantages of this new synthetic protocol lie in a simple potentially gram scale synthesis using inexpensive easily accessible reagents with no metal catalysts and no purification steps. Thus whereas the method reported previously to access the N,N′-dimethyl-3,3′-biquinoxalinium, “methylbiquinoxen” precursor gave higher yield than the new method reported here, this new method avoids the limitation of using scarce oxonium reagents. Overall, the new protocol is a robust synthetic strategy which offers new design possibilities.
Approaching the limit of CuII/CuI mixed valency in a CuIBr2-N-methylquinoxalinium hybrid compound
Leblanc, Nicolas,Sproules, Stephen,Pasquier, Claude,Auban-Senzier, Pascale,Raffy, Helene,Powell, Annie K.
, p. 12740 - 12743 (2015)
A novel 1D hybrid salt (MQ)[CuBr2]∞ (MQ = N-methylquinoxalinium) is reported. Structural, spectroscopic and magnetic investigations reveal a minimal CuII doping of less than 0.1%. However it is not possible to distinguish CuI and CuII. The unusually close packing of the organic moieties and the dark brown colour of the crystals suggest a defect electronic structure.
Identification of N- or O-Alkylation of Aromatic Nitrogen Heterocycles and N-Oxides Using 1H–15N HMBC NMR Spectroscopy
Bateman, Lorraine M.,Breugst, Martin,Byrne, Peter A.,Flosbach, Niko T.,Sheehy, Kevin J.
supporting information, (2020/06/02)
A series of representative diazines and pyridine N-oxides were subjected to alkylation using several different alkylating agents. The 15N NMR chemical shifts (δN values) of the diazines, pyridine N-oxides and derived alkylation products were determined using 1H-15N HMBC NMR spectroscopy at natural 15N abundance. The changes in the 15N NMR chemical shifts (Δ(δN) values) that occurred on going from starting materials to products in these reactions were analyzed. N-alkylation of diazines resulted in large upfield shifts of the δN values of the alkylated nitrogen (of the order of 100 ppm or greater). While O-alkylation of pyridine N-oxides resulted in upfield shifts of the δN values of the N-(alkoxy)pyridinium nitrogen, the Δ(δN) values were of a much smaller magnitude (ca. –42 ppm) than those observed for N-alkylations of diazines. Nitrogen NMR spectroscopic data from the literature of relevance to alkylation of azines, diazines, azine N-oxides and diazine N-oxides was gathered together, and using this in tandem with our 15N NMR spectroscopic data, we have been able to corroborate our observations on the trends observed in the Δ(δN) values associated with N- and O-alkylation reactions of aromatic N-heterocycles and N-oxides. An analysis protocol that relies on synergistic evaluation of 1H-15N HMBC and 1H-13C HMBC NMR spectra has been developed that enables unambiguous diagnosis of the occurrence of N-alkylation of aromatic N-heterocycles and O-alkylation of aromatic N-oxides.
Antibacterial activity of quinoxalines, quinazolines, and 1,5-naphthyridines
Parhi, Ajit K.,Zhang, Yongzheng,Saionz, Kurt W.,Pradhan, Padmanava,Kaul, Malvika,Trivedi, Kalkal,Pilch, Daniel S.,Lavoie, Edmond J.
supporting information, p. 4968 - 4974 (2013/09/02)
Several phenyl substituted naphthalenes and isoquinolines have been identified as antibacterial agents that inhibit FtsZ-Zing formation. In the present study we evaluated the antibacterial of several phenyl substituted quinoxalines, quinazolines and 1,5-naphthyridines against methicillin-sensitive and methicillin-resistant Staphylococcus aureus and vancomycin-sensitive and vancomycin-resistant Enterococcus faecalis. Some of the more active compounds against S. aureus were evaluated for their effect on FtsZ protein polymerization. Further studies were also performed to assess their relative bactericidal and bacteriostatic activities. The notable differences observed between nonquaternized and quaternized quinoxaline derivatives suggest that differing mechanisms of action are associated with their antibacterial properties.
CYCLIZATION OF N-ALKYL AZINIUM CATIONS WITH BIFUNCTIONAL NUCLEOPHILES. 21. REGIOISOMERIC 1,3,4-THIADIAZINOQUINOXALINES
Baklykov, V. G.,Charushin, V. N.,Chupakhin, O. N.,Drozd, V. N.
, p. 465 - 469 (2007/10/02)
Thiobenzhydrazides undergo cyclization with N-alkyl-quinoxalinium salts to give 5-alkyl-substituted 1,4,4a,10,10a-hexahydro-1,3,4-thiadiazinoquinoxalines, which undergo isomerization to 10-alkyl-substituted thiadiazinoquinoxalines when they are hea
REACTION OF AZINIUM CATIONS.5.* ADDITION OF WATER AND METHANOL TO 1,4-DIAZINIUM CATIONS IN THE PRESENCE OF BASES. EQUILIBRIUM CONSTANTS AND PMR SPECTRA OF THE MONO- AND DIADDUCTS
Charushin, V. N.,Kazantseva, I. V.,Ponizovskii, M. G.,Egorova, L.G.,Sidorov, E.O.,Chupakhin, O. N.
, p. 1118 - 1125 (2007/10/02)
The PKR* values and equilibrium constants for the addition of hydroxide ions to 1,4-diazinium ions were determined by spectrophotometry.The ratios 1:1 and 1:2 of the methoxyl adducts of the 1,4-diazinium ions in the sodium methoxide-methanol-D4 system and the equilibrium constants for the transformations of the monoadducts into the diaddition products were determined by PMR spectroscopy.
CYCLIZATION OF N-ALKYLAZINIUM CATIONS WITH BISNUCLEOPHILES. 6.* CYCLOELIMINATION OF TETRAHYDRO-endo-FUROQUINOXALINES
Ponozovskii, M. G.,Chupakhin, O. N.,Charushin, V. N.,Aleksandrov, G. G.
, p. 1098 - 1103 (2007/10/02)
The reaction of an N-methylquinoxalinium salt with a β-diketone under thermodynamic-control conditions to 2,3-disubstituted tetrahydroquinoxaline via cycloelimination of the initially tetrahydro-endo-furoaquinoxaline.
