Some Quaternary Ammonium Salts of Quinoxalines

Easley, William K.; Bahner, Carl Tabb

doi:10.1021/ja01164a509

Cited by 7 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We then decided to alkylate 3 in order to overcome the inherent pH-dependent behavior of salts 6 . Analogously to 4-aminopyridine [21], only the sp 2 nitrogen atom of the quinoxaline moiety undergoes alkylation by methyl iodide or propyl iodide in MeCN for 2 days to afford 7a and 7b in 90 and 92% yields, respectively (Scheme 2). The dimethyl derivative 8 can be prepared using a stronger methylating agent such as trimethyloxonium tetrafluoroborate.…”

Section: Resultsmentioning

confidence: 99%

1,2,3,4-Tetrahydro-1,4,5,8-tetraazaanthracene revisited: properties and structural evidence of aromaticity loss

Heynderickx

Nénon

Siri

et al. 2019

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

The synthesis and properties of 1,2,3,4-tetrahydro-1,4,5,8-tetraazaanthracene (THTAA) – a heterocycle involving both >N–H donating and =N– accepting moieties – have been reinvestigated. Unlike previously reported, THTAA is a thermally stable compound that can be re-sublimed at 300–310 °C without decomposition. Controlled introduction of substituents at the nitrogen atoms of THTAA led to variation of its electron donor/acceptor capability that allowed fine-tuning the absorption properties. The propensity of these compounds and a number of its derivatives to form infinite chains involving >N–H···N= and >N–H···Hal−···N+ atoms is demonstrated by X-ray structure analysis. The DFT level optimized and experimental geometry of THTAA and its derivatives show considerable loss of aromaticity within the quinoxaline moiety.

show abstract

Section: Resultsmentioning

confidence: 99%

1,2,3,4-Tetrahydro-1,4,5,8-tetraazaanthracene revisited: properties and structural evidence of aromaticity loss

Heynderickx

Nénon

Siri

et al. 2019

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

show abstract

“…It thus appears that the introduction of the methyl group on the nitrogen to generate a quaternary nitrogen is required for the compound to be reduced by dithionite (−660 mV). Quaternary salts of pyrazine and quinoxalines can be N-methylated with methyl iodide. The diquaternary salts can only be prepared using oxonium salts, which are stronger alkylating reagents .…”

Section: Resultsmentioning

confidence: 99%

Identification of a Redox Active Thioquinoxalinol Sulfate Compound Produced by an Anaerobic Methane-Oxidizing Microbial Consortium

2019

View full text Add to dashboard Cite

The anaerobic oxidation of methane (AOM) mitigates the flux of methane from marine sediments into the water column. AOM is performed by anaerobic methanotrophic archaea (ANME) that reverse the methanogenesis pathway and partner bacteria that utilize the released reducing equivalents for sulfate reduction. Here, we investigated small-molecule extracts from sediment-free thermophilic enrichment cultures of ANME-1 and sulfate-reducing bacteria using ultraperformance liquid chromatography with high-resolution mass spectrometry. During the analysis, we discovered a novel thioquinoxalinol-containing redox molecule as a major component of the chemically derivatized small-molecule pool. This compound contains both a redox active quinoxaline heterocyclic ring and a thiol group. Additionally, the same core structure was identified that contains a sulfate ester on the hydroxyl group, which likely makes the molecule more water soluble. Hydrated versions of both structures were also observed as major compounds in the extracts. On the basis of reactions of model compounds such as quinoxalin-6-ol, the hydrated version appears to be formed from the addition of water to the dehydropyrazine ring followed by an oxidation. These thioquinoxalinol compounds, which represent completely new structures in biochemistry, may be involved in electron transport processes within and/or between ANME-1 and sulfate-reducing bacteria, may serve protective roles by reacting with toxic compounds such as hydrogen sulfide, or may transport sulfate as a sulfate ester into the sulfate-reducing bacteria.

show abstract

“…To realize the strategy for the synthesis of pyrrolo[1,2-a]quinoxalines denoted by the symbol C2 it could be possible to use the 1,3-dipolar cycloaddition of the quinoxalinium N-ylide, produced in situ by the reaction of 1-phenacylquinoxalium bromide with triethylamine, with various 1,3-dipolarophiles if the formation of the 1-phenacylquinoxalinium bromide proceeded well and without side processes. Unfortunately, 1-phenacylquinoxalinium bromide is formed with a yield of only 28% as a result of prolonged standing (one month) of the mixture of quinazoline and phenacyl bromide in chloroform solution [36]. Boiling of the reaction mixture for 3 h leads to resin formation.…”

Section: Cycloaddition Reactionsmentioning

confidence: 99%

Pyrrolo[1,2-a]quinoxalines based on quinoxalines (Review)

Мамедов

Калинин

2010

Chem Heterocycl Comp

View full text Add to dashboard Cite

Published data on methods for the synthesis of pyrrolo [1,2-a]quinoxalines, based on derivatives of quinoxalines and also on compounds that are not initially derivatives of quinoxalines or pyrroles are summarized and classified.Derivatives of pyrrolo[1,2-a]quinoxalines have valuable characteristics and, in particular, marked biological activity and are a subject of constant interest. In spite of this, however, data on the synthesis of these compounds remain disconnected. The only review [1], devoted to pyrroloquinoxalines and appearing in a monograph published in 1979, presents data mostly covering the period from 1965 to 1975. The review is devoted not only to the synthesis of pyrrolo[1,2-a]quinoxalines but also to the synthesis of pyrrolo[2,3-b]-, pyrrolo[3,4-b]-, and pyrrolo[1,2,3-de]quinoxalines and their physicochemical characteristics. While covering so many questions in a single review the authors simply present the existing information without analyzing the methods used for their synthesis. From the review it is difficult to form an opinion as to which of the methods is more promising and to think of any new methods for their synthesis.In the present review an attempt is made to examine all possible ways of assembling the pyrrolo-[1,2-a]quinoxaline skeleton from various fragments on the basis of an analysis of its structure. N N Pyrrolo[1,2-a]quinoxalines 1 2 3 4 5 6 7 8 9 Without touching on the integrity of the benzene ring, the creation of the pyrrolo[1,2-a]pyrazine system can be represented by one of five types of construction depending on the number of atoms entering into the composition of the initial fragments: A (9+0), B (8+1), C (7+2), D (6+3), E (6+2+1 or 6+1+2); the number of

show abstract

Some Quaternary Ammonium Salts of Quinoxalines

Cited by 7 publications

References 0 publications

1,2,3,4-Tetrahydro-1,4,5,8-tetraazaanthracene revisited: properties and structural evidence of aromaticity loss

1,2,3,4-Tetrahydro-1,4,5,8-tetraazaanthracene revisited: properties and structural evidence of aromaticity loss

Identification of a Redox Active Thioquinoxalinol Sulfate Compound Produced by an Anaerobic Methane-Oxidizing Microbial Consortium

Pyrrolo[1,2-a]quinoxalines based on quinoxalines (Review)

Contact Info

Product

Resources

About