- Simple charge transfer complexes of some new and of some known heterocyclic compounds of selenium and tellurium
-
Charge transfer (CT) complexes (1:1) of 2,5-dihydrotellurophene and the 3-methyl and 3,4-dimethyl compounds with TCNQ and tetrachlorobenzoquinone (TCB) are reported.The organotellurium compounds failed to give complexes with p-dinitrobenzene (DNB).The variation of solid state (disc) conductivity with temperature and as a function of methyl substituents is considered.The complexes show semi-conducting behaviour and a consideration of these data, together with IR and UV spectroscopic data, in comparison with those for 1,3-dihydro-2-telluraindene given the following order of donor power with respect to TCNQ: With respect to a given donor, the order of acceptor power os TCNQ > TCB > DNB. 1,3-Dihydro-2-selenaindene forms a complex with TCNQ.The molecular ionisation potential of the selenaindene is 7.4 eV (by mass spectroscopy) and it has been shown that the compound may be electrochemically oxidized to materials such as C8H8SePF6.New quinoxalino-1-chalcogenacyclopentanes are reported; namely those derived from selenium, and the 7,8-dimethyl series, those based on both selenium and tellurium.Their preparation and characterisation are described, and their chemistry shown to be strongly analogous to that of quinoxalino-1-telluracyclopentane.CT complexes of the new SeII and TeII compounds (1:1) are prepared with TCNQ which are believed to be strongly ionic.
- Abid, Khalid Y.,McWhinnie, William R.
-
-
Read Online
- Synthesis of Thienoquinoxaline and Derivatives
-
The highly reactive o-quinonoid heterocycles thienoquinoxaline (1a) and its 6,7-dimethyl derivative (1b) have been synthesized by a base-catalyzed Pummerer reaction and isolated in crystalline form.In contrast, the 1,3-dibromothienoquinoxaline (8) could be characterized in solution but not isolated in pure form.The readily prepared 1,3-dihydrothienoquinoxaline (5a) underwent a direct Knoevenagel condensation with thiophene-2-carboxaldehyde to give the stilbenoid 14a.Sulfide 5a was also converted in a two-step process to the stable 1,3-diformylthienoquinoxaline 11a.
- Pohmer, Joerg,Lakshmikantham, M. V.,Cava, Michael P.
-
-
Read Online
- Pharmacological investigation of quinoxaline-bisthiazoles as multitarget-directed ligands for the treatment of Alzheimer's disease
-
Alzheimer's disease (AD) is the most prevalent disease of old age leading to dementia. Complex AD pathogenesis involves multiple factors viz. amyloid plaque formation, neurofibrillary tangles and inflammation. Herein we report of a new series of quinoxaline-bisthiazoles as multitarget-directed ligands (MTDLs) targeting BACE-1 and inflammation concurrently. Virtual screening of a library of novel quinoxaline-bisthiazoles was performed by docking studies. The most active molecules from the docking library were taken up for synthesis and characterized by spectral data. Compounds 8a-8n showed BACE-1 inhibition in micro molar range. One of the compounds, 8n showed BACE-1 inhibition at IC50 of 3 ± 0.07 μM. Rat paw edema inhibition in acute and chronic models of inflammation were obtained at 69 ± 0.45% and 55 ± 0.7%, respectively. Compound 8n also showed noteworthy results in AlCl3 induced AD model. The treated rats exhibited excellent antiamnesic, antiamyloid, antioxidant, and neuroprotective properties. Behavioural parameters suggested improved cognitive functions which further validates the testimony of present study. Moreover, compound 8n was found to have inherent gastrointestinal safety. This new string of quinoxaline-bisthiazoles were identified as effective lead for the generation of potent MTDLs and compound 8n was found to showcase qualities to tackle AD pathogenesis.
- Sagar, Sneha R.,Singh, Devendra Pratap,Das, Rajesh D.,Panchal, Nirupa B.,Sudarsanam, Vasudevan,Nivsarkar, Manish,Vasu, Kamala K.
-
-
- A new facile, efficient synthesis and structure peculiarity of quinoxaline derivatives with two benzimidazole fragments
-
A highly efficient and versatile method for the synthesis of quinoxaline derivatives with two benzimidazole fragments have been developed on the basis of the ring contraction of 3-(benzimidazo-2-yl)quinoxalin-2(1H)-one with 1,2-diaminobenzene and its various types of substituted and condensed derivatives. Owing to the inter- and intramolecular processes, involving self association, proton exchange, conformational, and/or tautomeric exchanges between several forms for most of the bis-benzimidazolylquinoxalines signals of bridged and neighboring carbon atoms and the hydrogen atoms of the neighboring carbon atoms of benzimidazole fragments in the NMR spectra are broadened. The conjugation between the benzimidazole fragments and the quinoxaline core of the molecules is increased from the quinoxaline derivative (10c) to its thiadiazol[f]- (17) and pyrrolo[a]-(19) annulated derivatives, resulting in a greater planarity of the molecule as a whole.
- Mamedov, Vakhid A.,Zhukova, Nataliya A.,Syakaev, Victor V.,Gubaidullin, Aidar T.,Beschastnova, Tat'Yana N.,Adgamova, Dil'Bar I.,Samigullina, Aida I.,Latypov, Shamil K.
-
supporting information
p. 1403 - 1416
(2013/02/23)
-
- Synthesis and antimicrobial activity of 2,3-bis(bromomethyl)quinoxaline derivatives
-
We synthesized 12 derivatives of 2,3-bis(bromomethyl)quinoxaline with substituents at the 6- and/or 7-positions, and evaluated their activities against bacteria and fungi. Of the 12 compounds, nine (1a-h, 1j, and 1k) showed antibacterial activity. The derivative 1g, which bears a trifluoromethyl group at the 6-position, showed the highest activity against Gram-positive bacteria, while 1c, which has a fluoro-group at the 6-position, showed the widest antifungal activity spectrum. However, only the derivative with an ethyl ester substitution, 1k showed activity against Gram-negative bacteria.
- Ishikawa, Hisato,Sugiyama, Takayuki,Kurita, Keisuke,Yokoyama, Akihiro
-
experimental part
p. 1 - 5
(2012/05/04)
-
- Facile synthesis of 6,6,8,6,6-ring fused pentacyclic heterocycles: annelation of quinolines to quinoxalines under PTC condition
-
An efficient and simple synthesis of pentacyclic quinolonoquinoxalinooxazocines in a one-pot sequence has been performed by unique application of phase transfer catalysis. Preparative simplicity and conceptual novelty of the methodology offer an attractive general application for the synthesis of novel quinoline antibiotics.
- Paira, Priyankar,Paira, Rupankar,Hazra, Abhijit,Naskar, Subhendu,Sahu, Krishnendu B.,Saha, Pritam,Mondal, Shyamal,Maity, Arindam,Banerjee, Sukdeb,Mondal, Nirup B.
-
body text
p. 4619 - 4623
(2009/10/26)
-
- Potent Quinoxaline-Spaced Phosphono α-Amino Acids of the AP-6 Type as Competitive NMDA Antagonists: Synthesis and Biological Evaluation
-
A series of α-amino-3-(phosphonoalkyl)-2-quinoxalinepropanoic acids was synthesized and evaluated for NMDA receptor affinity using a CPP binding assay.Functional antagonism of the NMDA receptor complex was evaluated in vitro using a stimulated TCP binding assay and in vivo by empolying an NMDA-induced seizure model.Some analogues also were evaluated in the -glycine binding assay.Several compounds of the AP-6 type show potent and selective NMDA antagonistic activity both in vitro and in vivo.In particular α-amino-7-chloro-3-(phosphonomethyl)-2-quinoxalinepropanoic acid (1) d isplayed an ED50 of 1.1 mg/kg ip in the NMDA lethality model.Noteworthy is α-amino-6,7-dichloro-3-(phosphonomethyl)-2-quinoxalinepropanoic acid (3) with a unique dual activity, displaying in the NMDA receptor binding assay an IC50 of 3.4 nM and in the glycine binding assay an IC50 of 0.61 μM.
- Baudy, Reinhardt B.,Greenblatt, Lynne P.,Jirkovsky, Ivo L.,Conklin, Mary,Russo, Ralph J.,et al.
-
p. 331 - 342
(2007/10/02)
-
- QUINOXALINE PHOSPHONO-AMINO ACIDS
-
The compounds of the formula: STR1 in which Q is the quinoxaline nucleus; m is one of the integers 0, 1 or 2; n is one of the integers 1,2 or 3; or a pharmaceutically acceptable salt, alkyl ester or STR2 where R. sup.3 and R 4 are, independently, hydrogen, nitro, halo or methoxy, are NMDA antagonists useful in the treatment and prevention of central nervous system related pathological conditions resulting from overstimulation by excitatory amino acids.
- -
-
-