65614-67-7Relevant academic research and scientific papers
Immobilized Pd on a NHC-functionalized metal-organic FrameworkMIL-101(Cr): An efficient heterogeneous catalyst in the heck and copper-free Sonogashira coupling reactions
Niknam, Esmaeil,Panahi, Farhad,Khalafi-Nezhad, Ali
supporting information, (2021/01/12)
A heterogeneous palladium catalyst system based on immobilization of palladium moieties on a N-heterocyclic carbene (NHC) modified metal organic framework (MOF) was developed for the Heck and copper-free Sonogashira coupling reactions. In order to prepare this catalyst system, first, MIL-101(Cr) was functionalized with NHC moieties through a post synthetic modification (PSM) approach, and then Pd metal was stabilized on the prepered MIL-101(Cr)-NHC substrate. This material was characterized using various microscopic and spectroscopic techniques and then was used as an efficient heterogeneous Pd catalyst system in the Heck and copper-free Sonogashira reactions. Results of the heterogeneity tests showed that the Pd-NHC-MIL-101(Cr) catalyst can efficiently catalyzed these coupling reactions heterogeneously and no remarkable changes observed in the morphology and structure of MIL-101(Cr) template during the reaction progress. Also, existence of palladium nanoparticles immobilized on the MOF structure affirmed by the TEM and XPS analysis confirmed the oxidation state of Pd. A variety of alkene and alkyne derivatives were synthesized in good to excellent yields using this heterogeneous Pd catalyst system under normal conditions. More importantly Pd-NHC-MIL-101(Cr) catalyst was simply recovered from the reaction medium without remarkable decreasing in its catalytic activities after five times of reusability. The ICP analysis showed the very low Pd and Cr metals leaching, representing high stability and applicability of this catalyst in Pd coupling reactions.
A facile tandem double-dehydrative-double-Heck olefination strategy for pot-economic synthesis of (E)-distyrylbenzenes as multi-target-directed ligands against Alzheimer's disease employing C. elegans model
Andhare, Nitin H.,Thopate, Yogesh,Shamsuzzama,Kumar, Lalit,Sharma, Tanuj,Siddiqi,Sinha, Arun K.,Nazir, Aamir
, p. 1655 - 1667 (2018/02/28)
A concise, one pot and regioselective access to (E)-distyrylbenzenes (DSBs) from arylhalide and secondary phenylenediethanol, a stable precursor for in situ generation of divinylbenzene (DVB) to avoid its polymerization, is described for construction of double C–C bond formation via tandem double-dehydrative-double-Heck (D-D-D-H) reaction using Palladium and ionic liquid [hmim]Br as a cooperative catalyst. It is noteworthy that this pot-economy approach also provides direct synthesis of hydroxylated distyrylbenzenes without requirement of protection-deprotection strategy. Importantly, the synthesized DSBs are tested for their protective activity against β amyloid reduction, acetylcholine esterase inhibition, lipid lowering and reactive oxygen species (ROS) reduction properties in transgenic Caenorhabditis elegans model wherein 1,3-bis((E)-4-(trifluoromethyl)styryl)benzene (5c) is found to be active across all above factors thus presenting lead molecule within multi-target-directed ligands (MTDLs) approach. Molecular docking studies were also performed to understand the interactions of potent DSBs with receptors.
Phenylenevinylene oligomers by Mizoroki-Heck cross coupling reaction. Structural and optoelectronic characterization
Estrada, Sandra E.,Ochoa-Puentes, Cristian,Sierra, Cesar A.
, p. 448 - 457 (2016/12/30)
In order to study the effect of the molecular structure on the optical properties of totally trans-trans phenylenevinylene oligomers (OPVs), sixteen 1,4-distyrylbenzene derivatives (1a-i and 2a-g) functionalized with different electron-donating (ED) and electron-withdrawing (EW) groups were synthesized by the Mizoroki-Heck cross coupling reaction in moderate to good yields (40–95%). The implemented methodology, with a small modification previously reported by our group, allows obtaining the desired vinyl configuration as well as one novel OPV compound (1h). After structural characterization by several techniques (e.g. FTIR, 1H, 13C and Solid-State NMR), particular emphasis was placed upon the investigation of their optical properties by UV–vis and fluorescence spectroscopies. The results showed that, with only one exception, the ED and EW groups at the ends of OPV systems lead to a bathochromic shift. This effect is intensified with the introduction of methoxy groups on the central ring. Consistent with these, the HOMO-LUMO gaps (ΔE) decreases as the strength of ED and EW substituents increases. The ED and EW substituents also lead to a decrease in the Φf values. This contribution in the area of organic electronics can be used as a reference to better select the most appropriate technological application for each OPV and this can be extrapolated to their respective structurally analogous segmented polymer.
Hydroxylated di- and tri-styrylbenzenes, a new class of antiplasmodial agents: Discovery and mechanism of action
Sharma, Naina,Mohanakrishnan, Dinesh,Shard, Amit,Sharma, Abhishek,Sinha, Arun K.,Sahal, Dinkar
, p. 49348 - 49357 (2016/07/06)
The first systematic evaluation of the antiplasmodial activity of the hydroxystilbene family of natural products and di/tristyrylbenzenes is described. A library of 27 diversely substituted hydroxy stilbenoids was rapidly synthesized using modified Knoevenagel-Perkin-decarboxylation-Heck sequences from readily available starting materials (i.e. hydroxybenzaldehyde-phenylacetic acid-arylhalide). These compounds were evaluated for in vitro antiplasmodial activity against three different strains of Plasmodium falciparum. Notably, 4,4′4′′-((1E,1′E,1′′E)-benzene-1,3,5-triyltris(ethene-2,1-diyl))tris(2,6-dimethoxyphenol) (27), an octupolar stilbenoid, showed IC50 (μM) values of 0.6, 0.5 and 1.36 while a distyrylbenzene (11) showed IC50 values of 0.9, 2.0 and 2.7 against 3D7 (chloroquine sensitive), Dd2 and Indo (chloroquine resistant) strains of Plasmodium falciparum respectively. Moreover, 27 and 11, which exhibited selectivity indices of 40 and >111 were also found to be nontoxic to the HeLa cell line. Microscopic studies revealed that the rings and trophozoites obtained from the 27 and 11 (an octupolar tristyrylbenzene and distyrylbenzene respectively) treated cultures were growth inhibited and morphologically deformed. These cultures also showed DNA fragmentation and loss of mitochondrial membrane potential (ΔΨm), suggestive of apoptotic death of the parasite. Together, these studies introduce di/tristyrylbenzenes as a new class of antimalarial agents.
Molecular docking studies of (1E,3E,5E )-1,6-bis(substituted phenyl)-hexa-1,3,5-triene and 1,4-bis(substituted trans-styryl)benzene analogs as novel tyrosinase inhibitors
Ha, Young Mi,Lee, Hye Jin,Park, Daeui,Jeong, Hyoung Oh,Park, Ji Young,Park, Yun Jung,Lee, Kyung Jin,Lee, Ji Yeon,Moon, Hyung Ryong,Chung, Hae Young
, p. 55 - 65 (2013/03/14)
We simulated the docking of the tertiary structure of mushroom tyrosinase with our compounds. From the structure-tyrosinase inhibitory activity relationship, it is notable that compounds 4, 8 and 11 showed similar or better activity rates than kojic acid which was used as a positive control. Compounds 17, 21, and 23 among benzene analogs that possess the same substituent showed significantly lower tyrosinase inhibitory effects. Therefore, we have confirmed that among the compounds showing better tyrosinase inhibitory effects than kojic acid, the compounds with triene analogs have better tyrosinase inhibitory effect than the compounds with benzene analogs. Docking simulation suggested the mechanism of compounds by several key residues which had possible hydrogen bonding interactions. The pharmacophore model underlined the features of active compounds, 4,4′-((1E,3E,5E )-hexa-1,3,5-triene-1,6-diyl)diphenol, 5,5′-((1E,3E,5E )-hexa-1,3,5-triene-1,6-diyl)bis(2-methoxy-phenol), and 5,5′-((1 E,3E,5E )-hexa-1,3,5-triene-1,6-diyl)dibenzene-1,3-diol among triene derivatives which had several hydrogen bond groups on both terminal rings. The soundness of the docking results and the agreement with the pharmacophores suggest that it can be conveniently exploited to design inhibitors with an improved affinity for tyrosinase.
Tandem heck/decarboxylation/heck strategy: Protecting-group-free synthesis of symmetric and unsymmetric hydroxylated stilbenoids
Shard, Amit,Sharma, Naina,Bharti, Richa,Dadhwal, Sumit,Kumar, Rajesh,Sinha, Arun K.
supporting information, p. 12250 - 12253 (2013/02/22)
Ride the (micro)wave: The title strategy has been developed for the synthesis of various symmetric or unsymmetric hydroxylated stilbenoids utilizing 4-halophenols and acrylic acid as coupling partners (see scheme; DMA=N,N-dimethylacetamide, MW=microwave). Protecting groups are not necessary and a single palladium catalyst is used. Copyright
ONE POT MULTICOMPONENT SYNTHESIS OF SOME NOVEL HYDROXY STILBENE DERIVATIVES WITH ALPHA, BETA-CARBONYL CONJUGATION UNDER MICROWAVE IRRADIATION
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Page/Page column 9, (2012/07/13)
The present invention provides a method for the preparation of some novel multiconjugated 2- or 4-hydroxy substituted stilbenes. The method provides one pot multicomponent approach wherein 3-4 step reaction sequences viz. condensation, decarboxylation and Heck coupling occur simultaneously which results in an enhanced yield of desired products and reduced reaction times
Phenolic bis-styrylbenzenes as β-amyloid binding ligands and free radical scavengers
Flaherty, Daniel P.,Kiyota, Tomomi,Dong, Yuxiang,Ikezu, Tsuneya,Vennerstrom, Jonathan L.
, p. 7992 - 7999 (2011/03/19)
Starting from bisphenolic bis-styrylbenzene DF-9 (4), β-amyloid (Aβ) binding affinity and specificity for phenolic bis-styrylbenzenes, monostyrylbenzenes, and alkyne controls were determined by fluorescence titration with β-amyloid peptide Aβ1-40 and a fluorescence assay using APP/PS1 transgenic mouse brain sections. Bis-styrylbenzene SAR is derived largely from work on symmetrical compounds. This study is the first to describe Aβ binding data for bis-styrylbenzenes unsymmetrical in the outer rings. With one exception, binding affinity and specificity were decreased by adding and/or changing the substitution pattern of phenol functional groups, changing the orientation about the central phenyl ring, replacing the alkene with alkyne bonds, or eliminating the central phenyl ring. The only compound with an Aβ binding affinity and specificity comparable to 4 was its 3-hydroxy regioisomer 8. Like 4, 8 crossed the blood-brain barrier and bound to Aβ plaques in vivo. By use of a DPPH assay, phenol functional groups with para orientations seem to be a necessary, but insufficient, criterion for good free radical scavenging properties in these compounds.
Direct olefination of benzaldehydes into hydroxy functionalized oligo (p-phenylenevinylene)s via Pd-catalyzed heterodomino Knoevenagel- decarboxylation-Heck sequence and its application for fluoride sensing π-conjugated units
Sharma, Abhishek,Sharma, Naina,Kumar, Rakesh,Shard, Amit,Sinha, Arun K.
supporting information; experimental part, p. 3283 - 3285 (2010/07/13)
A new approach for one step olefination of benzaldehydes into hydroxy functionalized OPVs is achieved through the first domino Knoevenagel- decarboxylation-Heck sequence using a single catalyst system. The methodology also led to new oxygen based OPV scaffolds capable of selective and visible fluoride recognition in organic or aqueous medium.
Anomalous photophysics of bis(hydroxystyryl)benzenes: A twist on the para/meta dichotomy
Solntsev, Kyril M.,McGrier, Psaras L.,Fahrni, Christoph J.,Tolbert, Laren M.,Bunz, Uwe H. F.
supporting information; experimental part, p. 2429 - 2432 (2009/05/26)
(Chemical Equation Presented) The dianions of two isomeric bis(hydroxystyryl)benzenes show dramatically different photophysical properties.
