2379-55-7Relevant academic research and scientific papers
Optimisation of conoidin A, a peroxiredoxin inhibitor
Liu, Gu,Botting, Catherine H.,Evans, Kathryn M.,Walton, Jeffrey A. G.,Xu, Guogang,Slawin, Alexandra M. Z.,Westwood, Nicholas J.
, p. 41 - 45 (2010)
Lead optimisation: Interest in the inhibition of peroxiredoxin has been revitalised by their recently identified role in signalling cascades. Here, the synthesis and analysis of novel analogues of the peroxiredoxin inhibitor conoidin A is described. Computational methods are used to rationalise the generated SAR data. These studies lead to a proposed binding mode for this class of compounds that will aid the design of second generation inhibitors. (Figure Presented)
Variable temperature neutron diffraction analysis of a very short O-H;...O hydrogen bond in 2,3,5,6-pyrazinetetracarboxylic acid dihydrate: Synthon-assisted short Oacid-H...Owater hydrogen bonds in a multicenter array
Vishweshwar, Peddy,Babu, N. Jagadeesh,Nangia, Ashwini,Mason, Sax A.,Puschmann, Horst,Mondal, Raju,Howard, Judith A. K.
, p. 9406 - 9416 (2004)
The occurrence of short hydrogen bonds in pyrazine di-, tri-, and tetracarboxylic acid dihydrates was analyzed. A very short O- H···O hydrogen bond was characterized in one of the tetracids. The synergy from resonance and polarization assistance in the finite, neutral array was found to be sufficient to result in short O-H···H hydrogen bonds when the carboxylic acid donor is activated. This synthon-assisted hydrogen-bond shortening phenomenon was postulated from the neutron-diffraction crystal structure.
Isolation and determination of α-dicarbonyl compounds by RP-HPLC-DAD in green and roasted coffee
Daglia, Maria,Papetti, Adele,Aceti, Camilla,Sordelli, Barbara,Spini, Valentina,Gazzani, Gabriella
, p. 8877 - 8882 (2007)
Glyoxal, methylglyoxal, and diacetyl formed as Maillard reaction products in heat-treated food were determined in coffee extracts (coffee brews) obtained from green beans and beans with different degrees of roast. The compounds have been reported to be mutagenic in vitro and genotoxic in experimental animals in a number of papers. More recently, α-dicarbonyl compounds have been implicated in the glycation process. Our data show that small amounts of glyoxal and methylglyoxal occur naturally in green coffee beans. Their concentrations increase in the early phases of the roasting process and then decline. Conversely, diacetyl is not found in green beans and forms later in the roasting process. Therefore, light and medium roasted coffees had the highest glyoxal and methylglyoxal content, whereas dark roasted coffee contained smaller amounts of glyoxal, methylglyoxal, and diacetyl. For the determination of coffee α-dicarbonyl compounds, a reversed-phase high performance liquid chromatography with a diode array detector (RP-HPLC-DAD) method was devised that involved the elimination of interfering compounds, such as chlorogenic acids, by solid phase extraction (SPE) and their derivatization with 1,2-diaminobenzene to give quinoxaline derivatives. Checks of SPE and derivatization conditions to verify recovery and yield, respectively, resulted in rates of 100%. The results of the validation procedure showed that the proposed method is selective, precise, accurate, and sensitive.
Unexpected decomposition of a monoquarternated 4,4'-bipyridinium dication by disodium dithionite reduction in water
Scheytza, Holger,Reissig, Hans-Ulrich
, p. 1057 - 1062 (1999)
Instead of the expected neutral radical the reduction of a quinoxaline bridged 4,4-bipyridinium salt by disodium dithionite (DSD) in water renders 2,3-dimethylquinoxaline and 4,4'-bipyridine. In contrast, with more electron- rich arenes used as spacer groups no decomposition products were observed. The mechanism of the chemically induced decomposition and the electrochemical properties of the starting compounds are reported.
POTENTIAL ALARM PHEROMONES FROM THE MEDITERRANEAN OPISTHOBRANCH SCAPHANDER LIGNARIUS
Cimino, G.,Spinella, A.,Sodano, G.
, p. 5003 - 5004 (1989)
Two new ω-phenyl conjugated trienones, lignarenone-A (2) and lignarenone-B (3), are the main metabolites isolated from the dorsum acetone extract of Scaphander lignarius.Their structures, closely related to 3-methyl navenone-B (1) a minor component of the alarm pheromone mixture of the opisthobranch Navanax inermis, were characterized by spectral methods.
Isolation, identification, and quantification of roasted coffee antibacterial compounds
Daglia, Maria,Papetti, Adele,Grisoli, Pietro,Aceti, Camilla,Spini, Valentina,Dacarro, Cesare,Gazzani, Gabriella
, p. 10208 - 10213 (2007)
Coffee brew is a widely consumed beverage with multiple biological activities due both to naturally occurring components and to the hundreds of chemicals that are formed during the roasting process. Roasted coffee extract possesses antibacterial activity against a wide range of microorganisms, including Staphylococcus aureus and Streptococcus mutans, whereas green coffee extract exhibits no such activity. The naturally occurring coffee compounds, such as chlorogenic acids and caffeine, cannot therefore be responsible for the significant antibacterial activity exerted by coffee beverages against both bacteria. The very low minimum inhibitory concentration (MIC) found for standard glyoxal, methylglyoxal, and diacetyl compounds formed during the roasting process points to these α-dicarbonyl compounds as the main agents responsible for the antibacterial activity of brewed coffee against Sa. aureus and St. mutans. However, their low concentrations determined in the beverage account for only 50% of its antibacterial activity. The addition of caffeine, which has weak intrinsic antibacterial activity, to a mixture of α-dicarbonyl compounds at the concentrations found in coffee demonstrated that caffeine synergistically enhances the antibacterial activity of α-dicarbonyl compounds and that glyoxal, methylglyoxal, and diacetyl in the presence of caffeine account for the whole antibacterial activity of roasted coffee.
Synthesis and Chemistry of 1,3-Dihydrotelluroloquinoxaline and Derivatives: Crystal and Molecular Structure of 1,3-Dihydro-2,2-diiodo-2λ4-telluroloquinoxaline-2,3-Bis(iodomethyl)quinoxaline (1:1)
Singh, Harkesh B.,McWhinnie, William R.,Hamor, Thomas A.,Jones, Richard H.
, p. 23 - 28 (1984)
The reaction of 2,3-bis(bromomethyl)quinoxaline with tellurium and sodium iodide (2 h) gave the violet compound 1,3-dihydro-2,2-di-iodo-2λ4-telluroloquinoxaline (m.p. 158-160 deg C).The latter compound readily forms a black 1:1 complex with 7,7,8,8-tetracyanoquinodimethane.The u.v., n.m.r., i.r., and mass spectra of the new organotellurium heterocycles are presented and discussed. 2,3-Bis(bromomethyl)quinoxaline also reacts with tellurium and potassium iodide (1 h) to give a yellow material for which elemental analysis, n.m.r., and mass spectroscopy suggest a 1:1 adduct of the above di-iodo-complex and 2,3-bis(iodomethyl)quinoxaline.Sodium hydrogentelluride reduces 2,3-bis(bromomethyl)quinoxaline to 2,3-dimethylquinoxaline.The crystal and molecular structure of the 1:1 adduct of 1,3-dihydrotelluroquinoxaline, C10H8I2N2Te, with 2,3-bis(iodomethyl)quinoxaline, C10H8I2N2, has been determined.Crystals of the compound are triclinic, space group P, with a = 7.667(2), b = 11.826(4), c = 13.739(4) Angstroem, α = 93.26(3), β = 98.37(2), γ = 83.29(2) deg, and Z = 2.Final R = 0.059 for 2998 observed reflexions.The structure consists of discrete molecules of C10H8I2N2Te and C10H8I2N2, a pair of each being linked into centrosymmetric dimers by weak TI linkages.The co-ordination about tellurium is a distorted octahedron with two Te-C bonds , two axial Te-I bonds and two longer equatorial Te-I bonds trans to Te-C , the longer contact being to an iodine of the organic di-iodide.Large deviations of bond angle from the ideal octahedral angles occur.A further very weak interaction links the dimers into chains along x.No abnormal features are observed in the organic moieties.
Acceptorless dehydrogenative condensation: synthesis of indoles and quinolines from diols and anilines
Bellezza, Delia,Zaragozá, Ramón J.,José Aurell,Ballesteros, Rafael,Ballesteros-Garrido, Rafael
supporting information, p. 677 - 683 (2021/02/06)
The use of diols and anilines as reagents for the preparation of indoles represents a challenge in organic synthesis. By means of acceptorless dehydrogenative condensation, heterocycles, such as indoles, can be obtained. Herein we present an experimental and theoretical study for this purpose employing heterogeneous catalysts Pt/Al2O3and ZnO in combination with an acid catalyst (p-TSA) and NMP as solvent. Under our optimized conditions, the diol excess has been reduced down to 2 equivalents. This represents a major advance, and allows the use of other diols. 2,3-Butanediol or 1,2-cyclohexanediol has been employed affording 2,3-dimethyl indoles and tetrahydrocarbazoles. In addition, 1,3-propanediol has been employed to prepare quinolines or natural and synthetic julolidines.
In water organic synthesis: Introducing itaconic acid as a recyclable acidic promoter for efficient and scalable synthesis of quinoxaline derivatives at room temperature
Tamuli, Kashyap J.,Nath, Shyamalendu,Bordoloi, Manobjyoti
supporting information, p. 983 - 1002 (2021/02/27)
Substituted quinoxaline derivatives are traditionally synthesized by co-condensation of various starting materials. Herein, we describe a novel environmentally benign in water synthetic route for the synthesis of structurally and electronically diverse ninety quinoxalines with readily available substituted o-phenylenediamine and 1,2-diketones using cheap and biodegradable itaconic acid as a mild acid promotor in 1 hours. The reaction is performed at room temperature, which proceeds through cyclo-condensation reaction followed by obtaining the aforesaid nitrogen-containing heterocyclic adducts without performing the column chromatography up to 96% total yields. The simplicity, high efficiency, and reusable of the catalyst merits this reaction condition as “green synthesis” which enables it to be useful in synthetic transformations upto gram scale level.
Synthesis, biological evaluation, and in silico studies of new acetylcholinesterase inhibitors based on quinoxaline scaffold
Khongkow, Pasarat,Lomlim, Luelak,Nualnoi, Teerapat,Saetang, Jirakrit,Suwanhom, Paptawan,Tipmanee, Varomyalin
, (2021/08/20)
A quinoxaline scaffold exhibits various bioactivities in pharmacotherapeutic interests. In this research, twelve quinoxaline derivatives were synthesized and evaluated as new acetyl-cholinesterase inhibitors. We found all compounds showed potent inhibitory activity against acetyl-cholinesterase (AChE) with IC50 values of 0.077 to 50.080 μM, along with promising predicted drug-likeness and blood–brain barrier (BBB) permeation. In addition, potent butyrylcholinesterase (BChE) inhibitory activity with IC50 values of 14.91 to 60.95 μM was observed in some compounds. Enzyme kinetic study revealed the most potent compound (6c) as a mixed-type AChE inhibitor. No cytotoxicity from the quinoxaline derivatives was noticed in the human neuroblastoma cell line (SHSY5Y). In silico study suggested the compounds preferred the peripheral anionic site (PAS) to the catalytic anionic site (CAS), which was different from AChE inhibitors (tacrine and galanthamine). We had proposed the molecular design guided for quinoxaline derivatives targeting the PAS site. Therefore, the quinoxaline derivatives could offer the lead for the newly developed candidate as potential acetylcholinesterase inhibitors.
