120659-34-9Relevant academic research and scientific papers
Conformational profile, energy barriers and optical properties of quinquethiophene-S,S-dioxides
Bongini, Alessandro,Barbarella, Giovanna,Favaretto, Laura,Sotgiu, Giovanna,Zambianchi, Massimo,Casarini, Daniele
, p. 10151 - 10158 (2002)
Theoretical calculations, dynamic NMR experiments and absorption and photoluminescence data in solution are reported for a series of quinquethiophene S,S-dioxides substituted with alkyl groups of variable size and steric hindrance. Ab initio B3LYP/6-31G* and force field MM3 theoretical calculations show that the energy barriers for rotation around the inter-ring C-C bonds amount to a few kcal/mol even in the presence of very bulky substituents such as the cyclohexyl group. Dynamic NMR data were in agreement with the results of theoretical calculations. It was found that changing the steric hindrance of the substituents leaves the emission and photoluminesce properties unaltered. However, the photoluminesce intensities and wavelengths of all compounds were found to be very sensitive to solvent variations.
Targeted and selective HOMO energy control by fine regulation of molecular planarity and its effect on the interfacial charge transfer process in dye-sensitized solar cells
Zhang, Fengyu,Wang, Ran,Wang, Yajun,Zhang, Xiaomin,Liu, Bo
, p. 6256 - 6264 (2019)
In terms of the in-depth development of organic dyes, targeted and selective energy control is becoming a more and more important objective. Herein, four indoline sensitizers based on D-π-A-π-A construction were designed and synthesized with exactly the same donor and acceptor segments. Their molecular planarity was regulated by introducing various side chains into donor bridges. Interestingly, along with an improvement of planarity at a donor bridge, the HOMO levels of the dyes lift gradually, and more importantly, their LUMO levels remain at around the same value. Besides, better molecular planarity is obviously preferred to obtain higher charge injection efficiency but, an overly planar molecule may cause an overly high HOMO level, leading to poor dye regeneration efficiency. Furthermore, an appropriate side chain also restrains charge recombination to some extent, while an overly large side chain gives more chance for I3- to recombine with charge in the conduction band. Accordingly, our results demonstrated that regulation of planarity at a donor bridge not only provides targeted and selective control of the HOMO of the dye, but also enable fine adjustment with multiple interfacial charge transfer processes. Molecular planarity deserves to play an important role in the design of organic dyes, providing a significant strategy for the further development of organic sensitizers.
Suzuki Cross-Couplings of Unactivated Secondary Alkyl Bromides and Iodides
Zhou, Jianrong,Fu, Gregory C.
, p. 1340 - 1341 (2004)
The capacity to employ unactivated alkyl electrophiles as coupling partners will markedly increase the already exceptional utility of metal-catalyzed cross-coupling processes. This communication describes the development of a method that achieves the first Suzuki reactions of unactivated secondary alkyl bromides and iodides. The ability to couple readily available, easy-to-handle boronic acids is an attractive feature of this catalyst system. Copyright
C(SP3)-C(SP2) CROSS-COUPLING REACTION OF ORGANOZINC REAGENTS AND HETEROCYCLIC (PSEUDO)HALIDES
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Paragraph 163; 164, (2018/02/28)
Provided is a method of synthesizing a C(sp3)-C(sp2) cross-coupled compound comprising reacting a C(sp3) coupling partner with a C(sp2) coupling partner, a catalyst, and a solvent; wherein the C(sp3) coupling partner comprises an organic zinc reagent; and wherein the C(sp2) coupling partner comprises a heterocyclic halide or a heterocyclic pseudo halide. The method further comprises synthesis of the organic zinc reagent, wherein the synthesis comprises reacting a zinc powder with an acid, filtering, washing, and drying to obtain an activated zinc powder; and reacting the activated zinc powder with a metal iodide catalyst and a second solvent and heating for a predetermined time to obtain the organic zinc reagent.
Discovery of Highly Potent Pinanamine-Based Inhibitors against Amantadine- and Oseltamivir-Resistant Influenza A Viruses
Zhao, Xin,Li, Runfeng,Zhou, Yang,Xiao, Mengjie,Ma, Chunlong,Yang, Zhongjin,Zeng, Shaogao,Du, Qiuling,Yang, Chunguang,Jiang, Haiming,Hu, Yanmei,Wang, Kefeng,Mok, Chris Ka Pun,Sun, Ping,Dong, Jianghong,Cui, Wei,Wang, Jun,Tu, Yaoquan,Yang, Zifeng,Hu, Wenhui
, p. 5187 - 5198 (2018/06/04)
Influenza pandemic is a constant major threat to public health caused by influenza A viruses (IAVs). IAVs are subcategorized by the surface proteins hemagglutinin (HA) and neuraminidase (NA), in which they are both essential targets for drug discovery. While it is of great concern that NA inhibitor oseltamivir resistant strains are frequently identified from human or avian influenza virus, structural and functional characterization of influenza HA has raised hopes for new antiviral therapies. In this study, we explored a structure-activity relationship (SAR) of pinanamine-based antivirals and discovered a potent inhibitor M090 against amantadine-resistant viruses, including the 2009 H1N1 pandemic strains, and oseltamivir-resistant viruses. Mechanism of action studies, particularly hemolysis inhibition, indicated that M090 targets influenza HA and it occupied a highly conserved pocket of the HA2 domain and inhibited virus-mediated membrane fusion by locking the bending state of HA2 during the conformational rearrangement process. This work provides new binding sites within the HA protein and indicates that this pocket may be a promising target for broad-spectrum anti-influenza A drug design and development.
The Discovery of Citral-Like Thiophenes in Fried Chicken
Cannon, Robert J.,Curto, Nicole L.,Esposito, Cynthia M.,Payne, Richard K.,Janczuk, Adam J.,Agyemang, David O.,Cai, Tingwei,Tang, Xiao-Qing,Chen, Michael Z.
, p. 5690 - 5699 (2017/07/24)
The isomers of 3,7-dimethyl-2,6-octadienal, more commonly known together as citral, are two of the most notable natural compounds in the flavor and fragrance industry. However, both isomers are inherently unstable, limiting their potential use in various applications. To identify molecules in nature that can impart the fresh lemon character of citral while demonstrating stability under acidic and thermal conditions has been a major challenge and goal for the flavor and fragrance industry. In the study of fried chicken, several alkyl thiophenecarbaldehydes were identified by gas chromatography-mass spectrometry and gas chromatography-olfactometry that provided a similar citral-like aroma. The potential mechanism of formation in fried chicken is discussed. Furthermore, in order to explore the organoleptic properties of this structural backbone, a total of 35 thiophenecarbaldehyde derivatives were synthesized or purchased for evaluation by odor and taste. Certain organoleptic trends were observed as the length of the alkyl or alkenyl chain increased or when the chain was moved to different positions on the thiophene backbone. The 3-substituted alkyl thiophenecarbaldehydes, specifically 3-butyl-2-thiophenecarbaldehyde and 3-(3-methylbut-2-en-1-yl)-2-thiophenecarbaldehyde, exhibited strong citrus and citral-like notes. Several alkyl thiophenecarbaldehydes were tested in high acid stability trials (4 °C vs 38 °C) and outperformed citral both in terms of maintaining freshness over time and minimizing off-notes. Additional measurements were completed to calculate the odor thresholds for a select group of thiophenecarbaldehydes, which were found to be between 4.7-215.0 ng/L in air.
Iron-catalyzed arene alkylation reactions with unactivated secondary alcohols
Jefferies, Latisha R.,Cook, Silas P.
supporting information, p. 2026 - 2029 (2014/05/06)
A simple, iron-based catalytic system allows for the inter- and intramolecular arylation of unactivated secondary alcohols. This transformation expands the substrate scope beyond the previously required activated alcohols and proceeds under mild reaction conditions, tolerating air and moisture. Furthermore, the use of an enantioenriched secondary alcohol provides an enantioenriched product for the intramolecular reaction, thereby offering a convenient approach to nonracemic products.
Preparation, structure, and reactivity of nonstabilized organoiron compounds. Implications for iron-catalyzed cross coupling reactions
Fuerstner, Alois,Martin, Ruben,Krause, Helga,Seidel, Guenter,Goddard, Richard,Lehmann, Christian W.
, p. 8773 - 8787 (2008/12/23)
A series of unprecedented organoiron complexes of the formal oxidation states -2, 0, +1, +2, and +3 is presented, which are largely devoid of stabilizing ligands and, in part, also electronically unsaturated (14-, 16-, 17- and 18-electron counts). Specifically, it is shown that nucleophiles unable to undergo β-hydride elimination, such as MeLi, PhLi, or PhMgBr, rapidly reduce Fe(3+) to Fe(2+) and then exhaustively alkylate the metal center. The resulting homoleptic organoferrate complexes [(Me4Fe)(MeLi)] [Li(OEt2)]2 (3) and [Ph4Fe][Li(Et 2O)2][Li(1,4-dioxane)] (5) could be characterized by X-ray crystal structure analysis. However, these exceptionally sensitive compounds turned out to be only moderately nucleophilic, transferring their organic ligands to activated electrophiles only, while being unable to alkylate (hetero)aryl halides unless they are very electron deficient. In striking contrast, Grignard reagents bearing alkyl residues amenable to β-hydride elimination reduce FeXn (n = 2, 3) to clusters of the formal composition [Fe(MgX)2]n. The behavior of these intermetallic species can be emulated by structurally well-defined lithium ferrate complexes of the type [Fe(C2H4) 4][Li(tmeda)]2 (8), [Fe(cod)2][Li(dme)] 2 (9), [CpFe(C2H4)2][Li(tmeda)] (7), [CpFe(cod)][Li(dme)] (11), or [Cp*Fe(C2H4) 2][Li(tmeda)] (14). Such electron-rich complexes, which are distinguished by short intermetallic Fe-Li bonds, were shown to react with aryl chlorides and allyl halides; the structures and reactivity patterns of the resulting organoiron compounds provide first insights into the elementary steps of low valent iron-catalyzed cross coupling reactions of aryl, alkyl, allyl, benzyl, and propargyl halides with organomagnesium reagents. However, the acquired data suggest that such C-C bond formations can occur, a priori, along different catalytic cycles shuttling between metal centers of the formal oxidation states Fe(+1)/Fe(+3), Fe(0)/Fe(+2), and Fe(-2)/Fe(0). Since these different manifolds are likely interconnected, an unambiguous decision as to which redox cycle dominates in solution remains difficult, even though iron complexes of the lowest accessible formal oxidation states promote the reactions most effectively.
