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1.
It is found that 2,3-dimethylquinoxaline-l, 4-di-N-oxide reacts with formaldehyde only in the presence of alkaline reagents, and that independent of the amount of formaldehyde taken, 2-(-hydroxyethyl)-3-methyl- and 2, 3-bis ( -hydroxyethyl) quinoxaline-di-N-oxides are formed. Oxidation of quinoxaline derivatives of general formula VI gives the corresponding mono- and di-N-oxides.For Part X see [3]. 相似文献
2.
A. S. Elina 《Chemistry of Heterocyclic Compounds》1967,3(5):740-741
It is found that 2-chloroquinoxaline 1-N-oxide readily undergoes nucleophilic substitution with ammonia, alkalies, and 4-acetyl-aminobenzenesulfonamide, giving the 1-N-oxides of 2-amino,2-hydroxy, and 2-(4-acetylaminobenzenesulfonamido) derivatives of quinoxaline. Treatment of 2-chloroquinoxaline 1-N-oxide with thiourea or hydrazine leads not only to nucleophilic substitution, but also to oxidation-reduction processes, with formation of respectively 2-thio- and 2-aminoquinoxaline. With 2-bromomethylquinoxaline 1,2-di-N-oxide, replacement of the bromine by a thiuronium group is not accompanied by deoxidation of the nitrogen atoms. 相似文献
3.
用两种方法对 N,N′-二氧 -2 -甲基喹恶啉进行显色 :( 1 )在氢氧化钠介质中 ,在 70~ 80℃ ,N,N′-二氧 -2 -甲基喹恶啉水溶液产生异构化反应生成蓝色化合物 ,其浓度在 4.0~ 2 0 0× 1 0 - 3 mg/ m L范围符合比耳定律 ;( 2 )在亚硫酸氢钠 /浓硫酸介质中 ,在室温条件下 ,2 0~ 3 0 min后还原成淡黄绿到绿色化合物 ,在 1 0 .0~ 70 0× 1 0 - 3mg/ m L浓度范围符合比耳定律。此项研究为这类抗菌药物中间体提供了一种定量分析方法 相似文献
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V. M. Kazakova O. G. Sokol G. G. Dvoryantseva I. S. Musatova A. S. Elina 《Chemistry of Heterocyclic Compounds》1985,21(10):1164-1168
The redox properties of 1,4-dioxides of hydroxymethyl and formyl derivatives of quinoxaline were studied by means of EPR spectroscopy and polarography. The electrochemical reduction of the 1,4-dioxides proceeds in several steps with successive deoxidation and the formation of dianions of substituted quinoxalines and is also accompanied by an intramolecular redox process. The experimentally observed hfs constants in the EPR spectra of the anion radicals formed in the reduction are in agreement with the corresponding values calculated by the INDO method.See [1] for communication 1.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1412–1416, October, 1985.The authors thank I. A. Abronin for his assistance in performing the quantum-chemical calculations. 相似文献
6.
L. S. Postnikov 《Chemistry of Natural Compounds》2010,46(1):72-74
New quinoxaline derivatives were prepared by reaction of 2-quinoxalinehydroximoylbromide with the alkaloids anabasine, cytisine,
and salsoline. 相似文献
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8.
Kozhevnikov D. N. Kovalev I. S. Rusinov V. L. Chupakhin O. N. 《Russian Chemical Bulletin》2001,50(6):1068-1071
1,2,4-Triazine 4-oxides were found to enter into the reactions of nucleophilic substitution of hydrogen with S-nucleophiles (arenethiols) in the presence of acylating agents and trifluoroacetic acid. The reactions proceeded with loss of the N-oxide function to form 5-arylthio-1,2,4-triazines. 2-Amino-3-ethoxycarbonylpyrazine 1-oxides and 2-amino-4-oxopterin 8-oxides react with arenethiol analogously. 相似文献
9.
New quinoxaline derivatives were prepared by the reaction of 2-hydroxyquinoxaline 1 and alkyl or alkylaminoalkyl halides in dimethylformamide using potassium carbonate as a base. The hydroxyl group was readily converted into a thiol function by treatment with phosphorus pentasulfide and/or Lawesson's reagent in pyridine, and the subsequent alkylation of the thiol group was carried out under phase-transfer catalyst conditions. Chlorination of 1 was carried out with phosphorus oxychloride. Branching of alkylamino side chains to the 2-OH, 2-SH, and 2-Cl quinoxalines resulted in the synthesis of several compounds. Synthesis and alkylation of 2-hydroxy 7-nitroquinoxaline are also reported. 相似文献
10.
Two isomeric mono-N-oxides of 2-aminopyrazine and the 1,4-di-N-oxide have been synthesized. A marked fall in the capacity of these compounds for nucleophilic exchange reactions and for rearrangements in acid and alkaline media has been found, which distinguishes them from the corresponding N-oxides of 2-aminoquinoxaline.For part I, see [5]. 相似文献
11.
The noise-decoupled nitrogen-15 NMR spectra of ten pyridine N-oxides and two quinoline N-oxides have been obtained at the natural-abundance level by high-resolution NMR spectroscopy. Substituents at the 4-ring position of pyridine N-oxide, capable of resonance interaction with the N-O moiety, give fairly large shifts in the expected directions. Spectra taken in dimethyl sulfoxide solution give 5–20 ppm and 33–55 ppm downfield shifts with respect to the solutions of the same substances in 2,2,2-trifluoroethanol and trifluoroacetic acid. Solvent influences are discussed in terms of hydrogen bonding and protonation of the N-oxide oxygen. Carbon-13 chemical shifts and one-bond carbon-hydrogen coupling constants of some substituted pyridine N-oxides are reported and discussed. 相似文献
12.
Yeong-Jae Seok Kap-Seok Yang Seong-Tae Kim Won-Ki Huh Sa-Ouk Kang 《Journal of carbohydrate chemistry》2013,32(9):1085-1095
ABSTRACT The quinoxaline derivatives formed between dehydro-D-erythroascorbic acid (2) and o-phenylenediamine (3) were separated by preparative HPLC and their structures were analyzed by HPLC-MS, UV-vis spectrophotometry and 1H NMR spectroscopy. The reaction of 2 with an excess amount of 3 in 5% aq m-phosphoric acid gave three different products, depending on the concentration of 2: below 0.1 mM of 2, only 3-(D-glycero-1,2-dihydroxyethyl)quinoxaline-2-carboxylic γ-lactone (4) was produced, between 0.1 to 5 mM of 2, another product, 2,2′-anhydro-[2-hydroxy-3-(D-glycero-2,3-dihydroxypropanal-1-yl)quinoxaline] (5) was formed as well as 4, and over 10 mM of 2, the third product, 2,1′-anhydro-[2-hydroxy-4-(D-glycero-1,2-dihydroxyethyl)-1,5-benzodiazepin-3-one] (6) was formed as well as 4 and 5, with an overall production yield over 95%. Quinoxaline 6 was slowly converted to 4 via 5. Based on these results, it was concluded that all three products retain the lactone ring moiety of 2, and the most stable product is 4. Compounds 5 and 6 were produced with higher concentration of 2, but they were unstable and slowly converted to 4 in aqueous solution. A possible mechanism for this conversion was proposed. 相似文献
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Richard A. Hollins Lawrence H. Merwin Robin A. Nissan William S. Wilson Richard Gilardi 《Journal of heterocyclic chemistry》1996,33(3):895-904
2,6-Diamino-3,5-dinitropyridine 1-oxide has been prepared by mixed acid nitration of 2,6-diaminopyridine, followed by oxidation using hydrogen peroxide in acetic acid. 3,5-Dinitro-2,4,6-triaminopyridine has been prepared by oxidative amination of 2-chloro-3,5-dinitropyridine or 2,6-diamino-3,5-dinitropyridine using potassium permanganate in liquid ammonia, or by “vicarious nucleophilic amination” of 2,6-diarnino-3,5-dinitropyridine using hydroxylamine in aqueous potassium hydroxide. 3,5-Dinitro-2,4,6-triaminopyridine 1-oxide has been prepared by oxidation of 3,5-dinitro-2,4,6-triaminopyridine using hydrogen peroxide in acetic acid, and by “vicarious nucleophilic amination” of 2,6-diamino-3,5-dinitropyridine 1-oxide. Nmr spectroscopy and single crystal X-ray diffraction studies have shown that these compounds have the planar structures and intra- and inter-molecular hydrogen bonding necessary to confer on the materials the high density, the thermal and chemical stability, and the explosive insensitivity required for new insensitive energetic materials. 相似文献
15.
The N-oxides of 2- and 2,3-substituted pyrazines were synthesized. It was found that the synthesized 2-formylpyrazine N,N-dioxide, in which the aldehyde group is in the hydrated form, undergoes redox transformations leading to deoxidation of one of the ring nitrogens and oxidation of the dihydroxymethyl group to a carboxyl group under the influence of alkaline reagents.See [10] for communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1275–1280, September, 1972. 相似文献
16.
Azine N-oxides undergo highly regioselective metalation with TMPZnCl·LiCl under mild conditions. A palladium-catalyzed Negishi cross-coupling reaction of the resulting organozinc species with heteroaromatic bromides provides heterobiaryls specifically oxidized at one nitrogen position in up to 95% yield. 相似文献
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A. S. Elina L. G. Tsyrul'nikova E. M. Peresleni Yu. N. Sheinker 《Chemistry of Heterocyclic Compounds》1966,2(1):72-78
Acyl derivatives of 2-aminoquinoxaline and their 1-N -oxides, as well as methyl derivatives of some of those compounds, are synthesized. IR spectra of these compounds in the solid state, and UV spectra of their solutions, showed that, with respect to the ability of its 2-acylamino derivatives to tautomerize to the imido form, quinoxaline is close to pyrimidine, and below quinoline and pyridine. With respect to the amideimide tautomerism equilibrium position, N-oxides of 2-acylaminoquinoxalines differ little from acylamides of quinoxaline themselves. The action of benzene sulfochloride on 2-aminoquinoxaline-1-N-oxide in pyridine below 0°leads to deoxidation of the N O group, and introduction of the benzene sulfonyloxy group at position 3 in the quinoxaline ring.For Part VIII see [17]. 相似文献