1479-24-9Relevant academic research and scientific papers
Investigations of luminescent behavior and intramolecular energy transfer mechanism of europium(III) complexes with fluorinated β-ketoester ligand
Devi, Rekha,Bala, Manju,Khatkar, S. P.,Taxak, V. B.,Boora, Priti
, p. 36 - 44 (2016)
A fluorinated β-ketoester ligand, ethyl-(2-fluorobenzoyl) acetate (EFBA) has been employed to synthesized new europium binary and ternary complexes with ancillary ligands neocuproine (neo), bathophenanthroline (batho), 1,10-phenanthroline (phen) and 2,2-bipyridyl (bipy) in high yield by the solution precipitation method. The ligand (EFBA) and the synthesized complexes Eu(EFBA)3·(H2O)2 (C1), Eu(EFBA)3·neo (C2), Eu(EFBA)3·batho (C3), Eu(EFBA)3·phen (C4), Eu(EFBA)3·bipy (C5) were characterized by elemental analysis, 1H NMR, IR, UV-vis, thermal analysis (TG/DTG) and luminescence spectroscopy. The thermal analysis results show that the complex is stable up to 231 °C temperature which is sufficient for the normal working of OLEDs. The luminescence measurements indicate that π electron rich organic ligand ethyl-(2-fluorobenzoyl) acetate possessing high absorption coefficient acts as a suitable chromophoric moiety for the transfer of energy to the central Eu3+ ion by the process of sensitization, this results in strong emissions band in red spectral region attributed to electric dipole 5D0 → 7F2 transition of europium ion. The luminescence intensity further enhanced by the introduction of N-containing ancillary ligands neocuproine, bathophenanthroline, 1,10-phenanthroline, and 2,2-bipyridyl in the ternary complexes C2-C5 because these ligands replace the solvent molecule in the coordination sphere and satisfy the coordination number around central europium ion. The sensitization process in europium complexes is investigated through the proposed energy transfer mechanism. The decay curves observations show the similar chemical environment around the europium ion in all the complexes.
Amide/Ester Cross-Coupling via C-N/C-H Bond Cleavage: Synthesis of β-Ketoesters
Chen, Jiajia,Joseph, Devaneyan,Xia, Yuanzhi,Lee, Sunwoo
, p. 5943 - 5953 (2021/04/02)
Activated primary, secondary, and tertiary amides were coupled with enolizable esters in the presence of LiHMDS to obtain good yields of β-ketoesters at room temperature. Notably, this protocol provides an efficient, mild, and high chemoselectivity method
Construction of isoxazolone-fused phenanthridinesviaRh-catalyzed cascade C-H activation/cyclization of 3-arylisoxazolones with cyclic 2-diazo-1,3-diketones
Hu, Wangcheng,He, Xinwei,Zhou, Tongtong,Zuo, Youpeng,Zhang, Shiwen,Yang, Tingting,Shang, Yongjia
supporting information, p. 552 - 556 (2021/02/06)
A Rh(iii)-catalyzed cascade C-H activation/intramolecular cyclization of 3-aryl-5-isoxazolones with cyclic 2-diazo-1,3-diketones was described, leading to the formation of isoxazolo[2,3-f]phenanthridine skeletons. The protocol features the simultaneous one-pot formation of two new C-C/C-N bonds and one heterocycle in moderate-to-good yields with good functional group compatibility. It is amenable to large-scale synthesis and further transformation.
Iridium-Catalyzed Enantioselective and Diastereoselective Hydrogenation of Racemic β’-Keto-β-Amino Esters via Dynamic Kinetic Resolution
He, Jiayin,Huang, An,Ling, Fei,Wang, Shiliang,Wang, Yifan,Wang, Ze,Zhao, Xianghua,Zhong, Weihui
supporting information, p. 4714 - 4719 (2021/09/02)
An iridium/f-diaphos catalytic system for the enantioselective hydrogenation of α-substituted β-ketoesters via dynamic kinetic resolution is reported. The desired anti β’-hydroxy-β-amino esters were obtained in moderate to good yields (60–95%) with 72–99% ees and 91:9 to 99:1 drs. This protocol tolerates various functional groups and could be easily conducted on gram scale with lower catalyst loading (TON up to 9100). (Figure presented.).
Synthesis of Dithiolethiones and Identification of Potential Neuroprotective Agents via Activation of Nrf2-Driven Antioxidant Enzymes
Bai, Feifei,Fang, Jianguo,Song, Zi-Long,Zhang, Baoxin
, p. 2214 - 2231 (2020/03/06)
Oxidative stress is implicated in the pathogenesis of a wide variety of neurodegenerative disorders, and accordingly, dietary supplement of exogenous antioxidants or/and upregulation of the endogenous antioxidant defense system are promising for therapeutic intervention or chemoprevention of neurodegenerative diseases. Nrf2, a master regulator of the cellular antioxidant machinery, cardinally participates in the transcription of cytoprotective genes against oxidative/electrophilic stresses. Herein, we report the synthesis of 59 structurally diverse dithiolethiones and evaluation of their neuroprotection against 6-hydroxydopamine-or H2O2-induced oxidative damages in PC12 cells, a neuron-like rat pheochromocytoma cell line. Initial screening identified compounds 10 and 11 having low cytotoxicity but conferring remarkable protection on PC12 cells from oxidative-mediated damages. Further studies demonstrated that both compounds upregulated a battery of antioxidant genes as well as corresponding genes' products. Significantly, silence of Nrf2 expression abolishes cytoprotection of 10 and 11, indicating targeting Nrf2 activation is pivotal for their cellular functions. Taken together, the two lead compounds discovered here with potent neuroprotective functions against oxidative stress via Nrf2 activation merit further development as therapeutic or chemopreventive candidates for neurodegenerative disorders.
3-pyridinesulfonyl-1-N-heteropyrrole derivatives capable of treating peptic ulcer as well as preparation method and application thereof
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Paragraph 0083-0087, (2020/11/26)
The invention discloses 3-pyridinesulfonyl-1-N-heteropyrrole derivatives capable of treating peptic ulcer as well as a preparation method and application of the derivative, and particularly provides compounds as shown in a formula I, or pharmaceutically a
Design, Synthesis, and Biochemical Characterization of Non-Native Antagonists of the Pseudomonas aeruginosa Quorum Sensing Receptor LasR with Nanomolar IC50 Values
Blackwell, Helen E.,Manson, Daniel E.,Nyffeler, Kayleigh E.,O'Reilly, Matthew C.
, (2020/03/04)
Quorum sensing (QS), a bacterial cell-to-cell communication system mediated by small molecules and peptides, has received significant interest as a potential target to block infection. The common pathogen Pseudomonas aeruginosa uses QS to regulate many of its virulence phenotypes at high cell densities, and the LasR QS receptor plays a critical role in this process. Small molecule tools that inhibit LasR activity would serve to illuminate its role in P. aeruginosa virulence, but we currently lack highly potent and selective LasR antagonists, despite considerable research in this area. V-06-018, an abiotic small molecule discovered in a high-throughput screen, represents one of the most potent known LasR antagonists but has seen little study since its initial report. Herein, we report a systematic study of the structure-activity relationships (SARs) that govern LasR antagonism by V-06-018. We synthesized a focused library of V-06-018 derivatives and evaluated the library for bioactivity using a variety of cell-based LasR reporter systems. The SAR trends revealed by these experiments allowed us to design probes with 10-fold greater potency than that of V-06-018 and 100-fold greater potency than other commonly used N-acyl-l-homoserine lactone (AHL)-based LasR antagonists, along with high selectivities for LasR. Biochemical experiments to probe the mechanism of antagonism by V-06-018 and its analogues support these compounds interacting with the native ligand-binding site in LasR and, at least in part, stabilizing an inactive form of the protein. The compounds described herein are the most potent and efficacious antagonists of LasR known and represent robust probes both for characterizing the mechanisms of LuxR-type QS and for chemical biology research in general in the growing QS field.
Desymmetrization of meso-dicarbonatecyclohexene with β-Hydrazino carboxylic esters via a Pd-catalyzed allylic substitution cascade
Xu, Kai,Zheng, Yan,Ye, Yong,Liu, Delong,Zhang, Wanbin
supporting information, p. 8836 - 8841 (2020/11/30)
The desymmetrization of meso-dicarbonatecyclohexene with β-hydrazino carboxylic esters has been achieved via a RuPHOX/Pd-catalyzed allylic substitution cascade for the construction of chiral hexahydrocinnoline derivatives with high performance. Mechanistic studies reveal that the reaction exploits a pathway different from that of our previous work and that the first nitrogen nucleophilic process is the rate-determining step. The protocol could be conducted on a gram scale without any loss of catalytic behavior, and the corresponding chiral hexahydrocinnolines can undergo diverse transformations.
Development of 2-arylbenzo[: H] quinolone analogs as selective CYP1B1 inhibitors
Dong, Jinyun,Wang, Zengtao,Meng, Qingqing,Zhang, Qijing,Huang, Guang,Cui, Jiahua,Li, Shaoshun
, p. 15009 - 15020 (2018/04/30)
The CYP1B1 enzyme is regarded as a potential target for cancer prevention and therapy. Based on the structure of α-naphthoflavone (ANF), diverse 2-arylbenzo[h]quinolone derivatives were designed, synthesized and evaluated as selective CYP1B1 inhibitors. Compared with ANF, although few of the title compounds possessed comparable or slightly higher CYP1B1 inhibitory activity, these compounds displayed a significantly increased selectivity toward CYP1B1 over CYP1A2. Among them compounds 5e, 5g and 5h potently inhibited the activity of CYP1B1 with IC50 values of 3.6, 3.9 and 4.1 nM respectively, paralleled by an excellent selectivity profile. On the basis of predicted clogP values, these target compounds may exhibit improved water-solubility compared to ANF. In particular, 5h showed a great superiority in the reversal of CYP1B1-mediated docetaxel resistance in vitro. The current study may serve as a good starting point for the further development of more potent as well as specific CYP1B1 inhibitors capable of reversing CYP1B1-mediated anticancer-drug resistance.
PROCESSES FOR THE PREPARATION OF IVACAFTOR
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Page/Page column 49; 50, (2017/03/21)
The present invention provides processes for the preparation of ivacaftor using novel intermediates and a process for its preparation.
