The novel 1,4-bis(2,6-dibromo-4-formylphenoxy)butane (
3
), prepared from 3,5-dibromobenzaldehyde (
1
), reacted with different hydrazines
4a–4d
and active methylene containing compounds
9a–9d
to ...give the corresponding bis(hydrazones)
5a–5d
and bis(cinnamonitriles)
11a–11d
, respectively. Both bis(2-cyanoacetic acid hydrazide) derivative
5d
and bis(thioacrylamide) derivative
11a
were taken as synthetic precursors for the synthesis of the target molecules bis(pyridine-2(1H)-thione) derivative
10
and
13a–13c
and their bis(2-methylsulfanylpyridine) derivative
14
and
17a–17c
. Another synthetic route was designed to prepare the target molecules
14
and
17a–17c
in a better yield using pyridine-2(1H)-thione) derivative
15
and
19a–19c
. Characterization of the newly prepared compounds via elemental analyses and spectral data are established.
•New series of bis-thiazoles linked to 2-phenoxy-N-arylacetamide as novel hybrid molecules were designed and synthesized.•The isomeric bis(thiazoles) were prepared under similar reaction conditions ...by reacting the appropriate bis(thiosemicarbazone) with the corresponding α-haloketones.•All of the newly synthesized compounds were tested against four bacterial strains.•Compounds 8g and 8i have the most antibacterial activity against S. aureus and bacillus subtilis.•Molecular docking was performed to confirm the binding affinities of 8g and 8i.
The reaction of the appropriate bis(α-haloketones) with the corresponding thiosemicarbazones in EtOH at reflux in the presence of a few drops of TEA produced good yields of novel bis-thiazoles linked to 2-phenoxy-N-arylacetamide as novel hybrid molecules. The isomeric bis(thiazoles) were prepared under similar reaction conditions by reacting the appropriate bis(thiosemicarbazone) with the corresponding α-haloketones. All of the newly synthesized compounds were tested against four bacterial strains. Compounds 8g and 8i have the most antibacterial activity against S. aureus and Bacillus subtilis. The molecular docking studies supported our findings, which demonstrated that compounds 8g and 8i could fit with favorable binding energies in the active sites of bacterial DNA gyrase B and thymidylate kinase, respectively.
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•Syntheses of bidentate bis(NHC) ligands and their transition metal complexes.•Examples of bidentate bis(NHC) metals in various oxidation states.•Applications in photochemistry, alkane oxidation and ...transfer hydrogenation.
The advanced development of NHC chemistry has lead to an extensive array of NHC ligand classes varying in structural and electronic properties. Although monodentate NHC ligands are by far the most thoroughly studied, multi-dentate NHC ligands including bidentate, pincer, scorpionate and macrocyclic motifs along with their corresponding transition metal complexes are widely reported in the literature. The unique structural and electronic properties along with high degree of modularity inherent to NHC ligands has made them ideal candidates for the inclusion in chelate rings affording intriguing reactivity consequences in a wide range of transition metal-mediated reactions. This short review focuses on the recent developments of bidentate bis(NHC) transition metal complexes and their applications in contemporary metal-mediated reactions such as alkane oxidation, transfer hydrogenation and photochemical transformations.
The reaction of the appropriate α-haloketones or α-keto-hydrazonoyl chlorides with the corresponding bis(hydrazinecarbothioamide) in EtOH at reflux in the presence of a few drops of TEA produced good ...yields of novel bis-thiazoles linked to diphenyl ether as novel hybrid molecules. Furthermore, some novel bis-thiazoles were obtained in high yields by reacting 1,1′-(oxybis(4,1-phenylene))bis(2-bromoethanone) with the appropriate thioamide. Furthermore, by reacting bis(2-bromoethanone) with the appropriate 4-amino-3-mercapto-1,2,4-triazole derivatives in ethanol in the presence of TEA, novel bis(5,6-dihydro-s-triazolo3,4-bthiadiazines) linked to diphenyl ether moiety were obtained in good yields. Moreover, by reacting bis(2-bromoethanone) with the appropriate pyridinethiones in ethanolic sodium ethoxide at reflux, good yields of bis(thienopyridines) linked to diphenyl ether moiety were obtained. The structures of new compounds were confirmed using elements and spectral data.
Modern energetic motifs for military and civilian applications are most often evaluated using various criteria, for example, energetic properties, production costs, and safety issues. Given this ...background, the design of energetic materials requires a deep understanding of both detonation performance and molecular stability. Here a new family of energetic bis(nitroamino‐1,2,4‐triazolates), which exhibit good thermal stabilities, excellent detonation properties, and low sensitivities, has been designed. Furthermore, two hydroxylammonium bis(azolates) with pyrazole and tetrazole backbones were synthesized, and they exhibit energetic properties analogous to the triazoles. This work highlights the application potential of N‐bridged bis(azolates) as promising energetic materials.
Explosive: Energetic bis(nitroamino‐1,2,4‐triazolates) were prepared by an N‐bridging strategy and exhibited good thermal stabilities, excellent detonation properties, and low sensitivities. A detailed study involving different azole scaffolds showed that bis(triazolates) compete well with bis(tetrazolates) and bis(pyrazolates) with respect to energetic properties and molecular stabilities.
A novel naphtho1,2‐c:5,6‐c′bis(1,2,5thiadiazole)‐based narrow‐bandgap π‐conjugated polymer is designed for application in polymer solar cells. Remarkable power conversion efficiencies over 10% can ...be achieved based on both conventional and inverted device architectures with thick photoactive layers, which are processed by using chlorinated or nonhalogenated solvents, suggesting its great promise toward practical applications based on high‐throughput roll‐to‐roll processing.
A synthesis of novel bis-thiazoles, linked to quinoxaline as novel hybrid molecules, was accomplished in good yields by the reaction of the appropriate α-haloketones or α-keto-hydrazonoyl chlorides ...with the corresponding bis(hydrazinecarbothioamide) in ethanol/dimethylformamide (EtOH/DMF) at reflux in the presence of a few drops of triethylamine (TEA). The reaction of the appropriate thioamide with the corresponding bis(2-bromoethanone) yielded novel bis-thiazoles. Furthermore, by reacting bis(2-bromoethanone) with the appropriate 4-amino-3-mercapto-1,2,4-triazole derivatives, novel bis(5,6-dihydro-s-triazolo3,4-bthiadiazines) linked to quinoxaline moiety were obtained in good yields. The starting bis-thiosemicarbazone was obtained by reacting 1,1'-((quinoxaline-2,3-diylbis(oxy))bis(4,1-phenylene))diethanone with thiosemicarbazide in EtOH containing a few drops of acetic acid (AcOH) at reflux. On the other hand, the 1,1'-((quinoxaline-2,3-diylbis(oxy))bis(4,1-phenylene))bis(2-bromoethanone) was obtained from the corresponding bis(acetyl) derivative upon treatment with N-bromosuccinimide (NBS) in the presence of p-toluenesulfonic acid (p-TsOH), respectively. Structures of new compounds were confirmed using elemental analyses and spectral data.
The molecular hybridization of various compounds with known pharmacological activity is a particularly popular approach for the development of potential drugs with improved pharmacokinetic profiles. ...In this respect, a novel series of bis(1,4-dihydropyridine-3,5-dicarbonitrile), bis(decahydroacridine), bis(tetrahydrodipyrazolo3,4-b:4′,3′-epyridin), and bis(tetrahydropyrimido4,5-bquinoline-2,4,6-trione) derivatives linked to piperazine core via phenoxyethanone linkages were prepared via Hantzsch like reaction of the ((piperazine-1,4-diylbis(2-oxoethane-2,1-diyl))bis(oxy))dibenzaldehydes, with the appropriate active methylene containing reagents. Attempted synthesis of the target products via bis-alkylation of the appropriate phenol with 1,1′-(piperazine-1,4-diyl)bis(2-chloroethan-1-one) in different basic conditions were unsuccessful.
Bis(imidazolium)- and bis(ammonium)-dibis(salicylato)borate ionic liquids with variable alkyl chain and cyclic ring structures, were synthesized and then evaluated them as potential lubricant ...additives. The copper strip test results revealed noncorrosive properties of these ionic liquids. Introduction of halogen content in bis(imidazolium) ionic liquid by replacement of bis(salicylato)borate (BScB) anion with hexafluorophosphate (PF6 –), severely corroded the copper strip. Thermogravimetric results showed that bis(imidazolium) ionic liquids exhibited higher thermal stability than bis(ammonium) ionic liquids owing to compact structure provided by imidazolium rings, higher intermolecular interactions, smaller free volume and low steric hindrance. The lubrication properties of these ionic liquids as additives to synthetic lubricant poly(ethylene) glycol (PEG 200) were evaluated for steel balls. Results showed that bis(ammonium)- and bis(imidazolium)-(BScB)2 ionic liquids as additives significantly reduced both friction coefficient and wear of PEG 200. The structure of cations, particularly the variation in substituted alkyl chain length monitored the degree of reduction in friction and wear. The excellent lubrication properties were attributed to the formation of adsorbed tribo-thin film and tribochemical product during the tribo-contact. Being halogen-, phosphorus-, and sulfur-free, these ionic liquids (a) protects contact surfaces from tribo-corrosive events, (b) reduces the friction and wear, and (c) keep environment green and clean.
Many bis-1,3,4-thiadiazoles 7, 10a,b, 13a-c and bis-thiazoles 16a-d, 19a-d were synthesized from reaction of bis(hydrazonoyl) chloride 4 with a series of methyl carbodithioate and thiosemicarbazone ...derivatives. Their antimicrobial activities were evaluated with six selected microorganisms. Some of the prepared derivatives showed higher antimicrobial activity than the reference used. Furthermore, molecular docking of the most active compound 10 b and the active site of target enzymes were studied using MOE 2014.010 software package.
