- Comparative study of two new grid complexes: Synthesis, X-ray structure characterization, thermogravimetric, and spectroscopic properties
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The synthesis and characterization of two new grid complexes, [Ni 4(L)4(DMF)4]·2H2O (1) and [Mn4(L)4(DMF)4] (2) (where L is the anion of 3,5-dichlorosalicylaldehyde pyridine-2-formyl hydrazone), were investigated. X-ray crystal structure analysis reveals that the metal centers in both complexes exhibit slightly distorted square-bipyramidal coordination geometry. The dominating interaction of two adjacent grids for 1 and 2 is Cl...H hydrogen bonds. The halogen-hydrogen bond is a key factor to stabilize the crystal structure of chloro-substituted grid compounds. Thermogravimetric curves of 1 and 2 exhibit distinct weight loss stages at different temperatures and reflect the thermal stability of the complexes. Both UV-visible and fluorescence spectra of 1 and 2 indicate they have a stronger conjugated system and the same significant quenching ability compared with H2L. The ESI-MS spectra of 1 and 2 prove that the tetranuclear grids decompose in methanol/water solution.
- Wang, Yuan,Liu, Zheng,Wang, Yongliao,Gao, Jiongyang,Li, Yanhong
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- A quinoline-based selective ‘turn on’ chemosensor for zinc(II) via quad-core complex, and its application in live cell imaging
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An efficient quinoline-based fluorescent chemosensor (QLNPY) was successfully developed for the detection of zinc ions (Zn2+). This novel chemosensor displayed higher sensitivity and selectivity toward Zn2+ over other competitive metal ions accompanying with obvious fluorescence enhancement. The QLNPY-Zn2+ complex can be further used as a new fluorescent “turn-off” sensor for pyrophosphate (PPi) and sulfur ion (S2?) via a Zn2+ displacement approach. The limits of detection were calculated to be 3.8 × 10?8 M for Zn2+, 3.7 × 10?7 M for PPi and 4.9 × 10?7 M for S2?. The binding mechanism of QLNPY and Zn2+ was investigated through NMR, HR-MS analysis and further studied by crystallographic analysis. Additionally, further application of QLNPY for sequential bioimaging of Zn2+ and PPi was studied in HepG2 cells, suggesting that the quinoline-based chemosensor possesses great potential applications for the detection of intracellular Zn2+ and PPi in vivo.
- Fu, Haoran,Liu, Haiyang,Zhao, Lei,Xiao, Boren,Fan, Tingting,Jiang, Yuyang
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- Application of a novel cationic iridium(iii) complex as a red phosphor in warm white light-emitting diodes
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A novel red-emitting cationic iridium(iii) complex, [(Lm)2Ir(La)]PF6, (Lm: 2-(9-(2-ethylhexyl)-9H-carbazol-3-yl)benzo[d]thiazole, La: N,N-diphenyl-4-(5-(pyridin-2-yl)-1,3,4-oxadiazol-2-yl)aniline) was synthesized. Its ultraviolet-visible absorption and photoluminescent properties show that the complex can be efficiently excited by a 465 nm-emitting blue GaN chip, its decomposition temperature (Td) is 340 °C, and its relative emission intensity at 100 °C is 88.3% of 25 °C. Perfect red light with a CIE value of (0.65, 0.34) was obtained when it was used as a phosphor at 6.0 wt% blending concentration in epoxy resin in a blue GaN-based LED. A 465 nm-emitting blue GaN-based LED only using yellow-emitting Y3Al5O12:Ce3+ (YAG:Ce) as a phosphor (1.0 wt% in epoxy resin) emitted cold white, and its corresponding color rendering index (CRI) was 74.1, correlated color temperature (CCT) was 6026 K, and luminous efficiency (ηL) was 25.3 lm W-1. It became a neutral white light LED when the iridium(iii) complex was added at 0.5 wt%, the corresponding CRI was 79.5, CCT was 4004 K, and ηL was 32.6 lm W-1. It further became a warm white LED when the complex was blended at 1.0 wt% and 1.5 wt%, the corresponding CRI were 80.0 and 79.6, CCT were 3650 K and 3133 K, ηL were 25.5 lm W-1 and 22.8 lm W-1, and CIE values were (0.40, 0.39) and (0.43, 0.40), respectively. This complex is a promising red phosphor candidate for red LEDs and warm white LEDs.
- Meng, Guoyun,Chen, Zeyu,Tang, Huaijun,Liu, Yong,Wei, Liying,Wang, Zhengliang
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- Strong Equatorial Crystal Field Enhances the Axial Anisotropy and Energy Barrier for Spin Reversal Process in Yb2 Single Molecule Magnets
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The importance of equatorial crystal fields on magnetic anisotropy of ytterbium single molecule magnets (SMMs) is observed for the first time. Herein, we report three similar dinuclear ytterbium complexes with the formula [Yb2(3-OMe-L)2(DMF)2(NO3)2]?DMF (1), [Yb2(3-H-L)2(DMF)2(NO3)2]?DMF?H2O (2), and [Yb2(3-NO3-L)2(DMF)2(NO3)2] (3), [where 3-X-H2L=N′-(2-hydroxy-3-X-benzylidene)picolinohydrazide, X=OMe (1), H (2) NO2 (3)]. Detailed magnetic measurements reveal the presence of weak antiferromagnetic interactions between the Yb centers and a field-induced slow relaxation of magnetization in all complexes. A higher energy barrier for spin reversal was observed for complex 1 (Ueff=50 K) and it decreases in the order of 2 (47 K) to 3 (40 K). Notably, complex 1 shows a remarkable energy barrier within the frequency range of 1–850 Hz reported for Yb-based SMMs. Further, ab initio calculations show a higher axial anisotropy and lower quantum tunneling of magnetization (QTM) in the ground state for 1 compared to 2 and 3. It was also observed that the presence of a strong crystal field in the equatorial plane (when the ? O1?Yb?O3 bond angle is close to 90°) enhances the axial anisotropy and improves the SMM behavior in the studied complexes. Both the experimental and theoretical analysis of relaxation dynamics discloses that Raman and QTM play major role on slow relaxation process for all complexes. To provide more insight into the exchange interactions, broken-symmetry DFT calculations were performed.
- Mondal, Arpan,Konar, Sanjit
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- An efficient colorimetric and absorption ratiometric anion sensor based on a simple azo-azomethine receptor
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An efficient colorimetric and absorption ratiometric azo-azomethine receptor N'-((E)-2-hydroxy-5-((E)-(4-nitrophenyl)diazenyl)benzylidene)picolinohydrazide (L) based on phenolic and acyl hydrazine binding units was synthesized and characterized by FT-IR, 1H NMR, 13C NMR and HRMS method. The optical response of L towards different anions was studied by colorimetric, UV–vis and 1H NMR titration method. The results revealed that L had a selective colorimetric sensing ability for biologically important F?, AcO? and H2PO4? by changing color from pale yellow to blue by naked-eye. Interestingly, the sensor L demonstrated an absorption ratiometric response towards F? (1:2 complex) and H2PO4? (1:1 complex) during the recognition process. The detection limit of the sensor L towards F?, AcO? and H2PO4? was estimated to be 2.94 μM, 4.12 μM and 12 μM respectively. The recognition mechanism was attributed to hydrogen bonding and subsequent deprotonation process according to 1H NMR titration experiments.
- Li, Zheng,Wang, Shujun,Xiao, Liwei,Li, Xiaolong,Jing, Xuemin,Peng, Xiaoxia,Ren, Lilei
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- Synthesis and crystal structure of a novel pyridine acylhydrazone derivative as a “turn on” fluorescent probe for Al3+
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A novel acylhydrazone-based fluorescent probe HL was synthesized and characterized by 1H NMR, 13C NMR, mass spectrum (MS) and x-ray diffraction analysis. HL showed high selectivity and sensitivity towards Al3+ over other metal ions based on excited-state intramolecular proton transfer (ESIPT) and photo-induced electron transfer (PET) processes with a low detection limit (2.14 × 10?8 M) and reasonable pH application range (4.0–7.5). HL and Al3+ formed a 1:1 complex, leading to a remarkable fluorescence enhancement, which was confirmed by Job's plot experiments, 1H NMR and MS. Fluorescence titration experiments showed the fluorescence intensity of HL had good linearity with Al3+ concentration and can be used to detect Al3+ in real water samples.
- Cai, Xinping,Huang, Ai,Huang, Jiaqi,Huang, Shoushun,Peng, Huanan,Peng, Xiaoming,Xu, Shujuan,Zhou, Jingjing
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- Spectroscopic and theoretical studies on Cr (III), Mn (II) and Cu (II) complexes of hydrazone derived from picolinic hydrazide and O-vanillin and evaluation of biological potency
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Trivalent Cr (III) and divalent of both Mn (II) and Cu (II) complexes containing hydrazone ligands derived from the condensation of picolinohydrazide with O-vanillin were synthesised and characterized by elemental analysis, spectral and magnetic measurements. The suggested octahedral structures were confirmed by applying DFT optimization and conformational studies. The thermal decomposition behaviour of Mn (II) complex is discussed. The evaluation of kinetic parameters (Ea, A, ?H, ?S and ?G) of all thermal degradation stages have been evaluated using Coats-Redfern and Horowitz-Metzger approaches. The band gap results suggested that these complexes are semi-conductors and lie in same range of highly efficient photovoltaic materials. Antibacterial studies showed that higher activity of complexes than of ligands. Assay on the antioxidant activity (DPPH and SOD) of the above complexes revealed the high SOD-activity of Mn (II) complex and high DPPH-activity for ligand.
- Abou-Melha, Khlood S.,Al-Hazmi, Gamil A. A.,Althagafi, Ismail,El-Gamil, Mohammed M.,El-Metwaly, Nashwa M.,Elghalban, Marwa G.,Shaaban, Fathy
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- A novel turn-on fluorescent probe based on naphthalimide for the tracking of lysosomal Cu2+in living cells
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A novel fluorescent probe CuNI was synthesized and exhibited highly effective fluorescence detection ability for Cu2+ in aqueous solution (HOAc-NaOAc buffer, 10 mM, pH 5.0). CuNI was obtained by a simple condensation reaction between the aldehyde (MFNI, bearing the naphthalimide fluorescence group) and the 2-picolinyl hydrazide, which bears the Cu2+ recognized group. Under acidic conditions, CuNI showed turn-on fluorescence recognition of Cu2+ which could be readily distinguished with the naked eye under a 365 nm UV lamp and the detection limit is as low as 19.40 nM. It has been further demonstrated that CuNI was hydrolyzed under the action of Cu2+ and the significant increase of fluorescence is due to the obvious AIE effect of the hydrolysate MFNI. The application of the probe CuNI in imaging lysosomal Cu2+ in HepG2 cells has also been demonstrated. This journal is
- Xu, Tingting,Huang, Junjie,Fang, Min,Sui, Mingshuai,Zhu, Yujing,Shentu, Yupeng,Li, Cun,Zhu, Weiju
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- A Highly Selective and Sensitive Fluorescent Probe Recognition for Co2+in Aqueous Media Based on 8-Hydroxyquinolin-2-carbaldehyde-2-pyridylformylhydrazone Derivative
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A new (8-hydroxyquinolin-2-yl)methylene picolinohydrazide derivative (L) has been successfully synthesized and characterized. The probe L displays high selectivity to Co2+in CH3CN/HEPES (1:1, V/V, 10 mmol·L?1, pH=7.4) with a fluorescence "ON-OFF" response. The Co2+ion recognition event possesses some distinct features including rapid response, high selectivity and sensitivity, good anti-interference ability and being applicable within a wide pH range. Based on job's plot and ESI-MS studies, the 1:1 binding mode was proposed. The binding constant of L and Co2+is 1.63×108L·mol?1and the detection limit is 1.15 μmol·L?1. Natural water samples experiments revealed that probe L can be potentially applied to the detection of Co2+in real environment.
- Zhong, Keli,Zhao, Jie,Zhou, Xue,Hou, Shuhua,Bian, Yanjiang,Li, Jianrong,Tang, Lijun
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- The structural and magnetic properties of FeII and CoII complexes with 2-(furan-2-yl)-5-pyridin-2-yl-1,3,4-oxadiazole
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Two novel coordination compounds containing heterocyclic bidentate N,N-donor ligand 2-(furan-2-yl)-5-(pyridin-2-yl)-1,3,4-oxadiazole (fpo) were synthesized. A general formula for compounds originating from perchlorates of iron, cobalt, and fpo can be written as: [M(fpo)2(H2O)2](ClO4)2 (M = Fe(II) for (1) Co(II) for (2)). The characterization of compounds was performed by general physico-chemical methods—elemental analysis (EA), Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) in case of organics, and single crystal X-ray diffraction (sXRD). Moreover, magneto-chemical properties were studied employing measurements in static field (DC) for 1 and X-band EPR (Electron paramagnetic resonance), direct current (DC), and alternating current (AC) magnetic measurements in case of 2. The analysis of DC magnetic properties revealed a high spin arrangement in 1, significant rhombicity for both complexes, and large magnetic anisotropy in 2 (D = ?21.2 cm-1). Moreover, 2 showed field-induced slow relaxation of the magnetization (Ueff = 65.3 K). EPR spectroscopy and ab initio calculations (CASSCF/NEVPT2) confirmed the presence of easy axis anisotropy and the importance of the second coordination sphere.
- Zoufaly, Pavel,?i?már, Erik,Kuchár, Juraj,Herchel, Radovan
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- Linear-shaped Ln III 4 and Ln III 6 clusters constructed by a polydentate Schiff base ligand and a β-diketone co-ligand: structures, fluorescence properties, magnetic refrigeration and single-molecule magnet behavior
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Herein, ten new linear-shaped LnIII4 and LnIII6 clusters, with the formula [Ln4(acac)6L2(CH3O)2(CH3OH)4]·xCH3OH (Ln = Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6), and Tm (8), Hacac = acetylacetone), [Ln6(acac)4L4(CH3O)6]·xCH3OH (Er (7) and Yb (9)), and [Lu4(acac)6L2(OH)2]·2CH2Cl2 (10), based on a polydentate Schiff base ligand, H2L, and a β-diketone co-ligand were successfully synthesized and structurally characterized. Single crystal X-ray diffraction measurements reveal that the structures of the clusters 1-6, 8 and 10 are very similar and their central Ln(iii) ions are linearly arranged Ln4; however, the clusters 7 and 9 possess a rare linearly arranged Ln6. The investigations on the solid-state fluorescence properties show that the clusters 2, 3, 5 and 6 display the characteristic lanthanum luminescence at room temperature. Magnetic studies reveal that weak antiferromagnetic interactions exist between adjacent Gd(iii) ions in cluster 4. More importantly, the cluster 4 exhibits significant MCE with the maximum -ΔSm value of 27.96 J kg-1 K-1 at 2.0 K and 7.0 T, whereas the cluster 6 displays a slow magnetic relaxation behavior under a zero dc field with the effective energy barrier ΔE/kB = 8.64 K and τ0 = 6.98 × 10-6 s.
- Wang, Wen-Min,He, Li-Yuan,Wang, Xin-Xin,Shi, Ying,Wu, Zhi-Lei,Cui, Jian-Zhong
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- Reinvestigation of the structure-activity relationships of isoniazid
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Isoniazid (INH) remains a cornerstone for treatment of drug susceptible tuberculosis (TB), yet the quantitative structure-activity relationships for INH are not well documented in the literature. In this paper, we have evaluated a systematic series of INH analogs against contemporary Mycobacterium tuberculosis strains from different lineages and a few non-tuberculous mycobacteria (NTM). Deletion of the pyridyl nitrogen atom, isomerization of the pyridine nitrogen to other positions, replacement of the pyridine ring with isosteric heterocycles, and modification of the hydrazide moiety of INH abolishes antitubercular activity. Similarly, substitution of the pyridine ring at the 3-position is not tolerated while substitution at the 2-position is permitted with 2-methyl-INH 9 displaying antimycobacterial activity comparable to INH. To assess the specific activity of this series of INH analogs against mycobacteria, we assayed them against a panel of gram-positive and gram-negative bacteria, as well as a few fungi. As expected INH and its analogs display a narrow spectrum of activity and are inactive against all non-mycobacterial strains evaluated, except for 4, which has modest inhibitory activity against Cryptococcus neoformans. Our findings provide an updated analysis of the structure-activity relationship of INH that we hope will serve as useful resource for the community.
- Hegde, Pooja,Boshoff, Helena I.M.,Rusman, Yudi,Aragaw, Wassihun Wedajo,Salomon, Christine E.,Dick, Thomas,Aldrich, Courtney C.
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- A simple Schiff base as dual-responsive fluorescent sensor for bioimaging recognition of Zn2+ and Al3+ in living cells
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A simple Schiff base fluorescent sensor (BDNOL) was synthesized from the reaction of picolinohydrazide and 4-(diethylamino)salicylaldehyde, and developed for selective detection of Al3+ and Zn2+. This non-fluorescent sensor displayed obvious fluorescence enhancement after binding to Al3+/Zn2+ ions with high sensitivity and selectivity, accompanied by obvious fluorescence emission enhancement (504 nm for Al3+ and 575 nm for Zn2+). The detection limits were found to be 8.30 × 10-8 M for Al3+ and 1.24 × 10-7 M for Zn2+. The binding mechanisms between BDNOL and Al3+/Zn2+ ions were supported by 1H NMR and HR-MS analysis, and a density functional theory (DFT) study. The sensing behavior was also studied with molecular logic functions of OR, AND, and NOT gates. Furthermore, the fluorescent sensor was successfully used to recognize Al3+ and Zn2+ in living cells, suggesting that this simple biosensor has great potential in biological imaging applications.
- Liu, Haiyang,Liu, Tianqi,Li, Jia,Zhang, Youming,Li, Jiahua,Song, Jun,Qu, Junle,Wong, Wai-Yeung
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- Cis and Trans Isomers of Fe(II) and Co(II) Complexes with Oxadiazole Derivatives - Structural and Magnetic Properties
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Four complexes with bidentate N,N-donors 2-(furan-2-yl)-5-(pyridin-2-yl)-1,3,4-oxadiazole (fpo) and 2-(pyridin-2-yl)-5-(thiophen-2-yl)-1,3,4-oxadiazole (pto) with general formula [M(L)2(NCS)2] (M=Co(II), L=fpo for (1); M=Co(II), L=pto for (2); M=Fe(II), L=fpo (3); M=Fe(II), L=pto (4)) are reported. Analysis and characterization of the samples was performed using standard physico-chemical techniques – elemental analysis, nuclear magnetic resonance, Fourier transform infrared spectroscopy, single-crystal X-ray diffraction. Magnetic properties for 1–4 revealed large magnetic anisotropy of Co(II) complexes, and AC susceptibility measurements confirmed their single-molecule magnetic behaviour. Furthermore, the theoretical calculations at DFT and CASSCF/NEVPT2 level of theory were exploited to better understand magnetism of these compounds.
- Zoufaly, Pavel,Kliuikov, Andrii,?i?már, Erik,Císa?ová, Ivana,Herchel, Radovan
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- Platinum(II) Complexes of Tridentate N∧N- ∧N -Coordinating Ligands Based on Imides, Amides, and Hydrazides: Synthesis and Luminescence Properties
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Five Pt(II) complexes are described in which the metal ion is bound to anionic (Formula presented.) -coordinating ligands. The central, deprotonated N atom is derived from an imide Ar?C(=O)?NH?C(=O)?Ar {PtL1–2Cl; Ar=pyridine or pyrimidine}, an amide py?C(=O)?NH?CH2?py {PtL3Cl}, or a hydrazide py?C(=O)?NH?N=CH?py {PtL4Cl}. The imide complexes PtL1–2Cl show no significant emission in solution but are modestly bright green/yellow phosphors in the solid state. PtL3Cl is weakly phosphorescent. PtL4Cl is formed as a mixture of isomers, bound through either the amido or imino nitrogen, the latter converting to the former upon absorption of light. Remarkably, the imino form displays fluorescence in solution, λ0,0=535 nm, whereas the amido shows phosphorescence, λ0,0=624 nm, τ=440 ns. It is highly unusual for two isomeric compounds to display emission from states of different spin multiplicity. The amido-bound PtL4Cl can act as a bidentate (Formula presented.) -coordinating ligand, demonstrated by the formation of bimetallic complexes with iridium(III) or ruthenium(II).
- Puttock, Emma V.,Sturala, Jiri,Kistemaker, Jos C. M.,Williams, J. A. Gareth
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- A chromone hydrazide Schiff base fluorescence probe with high selectivity and sensitivity for the detection and discrimination of human serum albumin (HSA) and bovine serum albumin (BSA)
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The discrimination and identification of human serum albumin (HSA) and bovine serum albumin (BSA) is very important, which is due to the vital roles of two SAs in biological and pharmaceutical research. Based on structural screening and docking calculation from a series of homologues, a coumarin Schiff base fluorescent probe 3-hydroxy-N′-((4-oxo-4H-chromen-3-yl)methylene)-2-naphthohydrazide (HCNH) has been designed and synthesized, which could effectively discriminate HSA and BSA. The probe HCNH exhibited superior sensitivity toward HSA and BSA with the detection limits of 10.62 nM and 16.03 nM in PBS solution, respectively. The binding mechanism of HCNH with SAs was studied by Job's plot analysis, SA destruction and displacement assay. Molecular docking and DFT methods were utilized to provide deep insight into the spatial conformation change of HCNH and binding sites in HSA/BSA. The conformation of HCNH was significantly influenced by the microenvironment provided by HSA and BSA, therefore its fluorescence emission was affected correspondingly. Non-toxic probe HCNH could be successfully used for fluorescence bio-imaging of HSA in cancer cells, which is significantly different from normal cells and favors the application in medical diagnosis.
- Fan, Jing,Li, Qing-Zhong,Li, Zhe,Liu, Hai-Bo,Wang, Zhi-Gang,Xie, Cheng-Zhi,Xu, Jing-Yuan,Yan, Xiao-Jing
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- Synthesis and Characterization of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes with 2-Carboxy benzaldehyde Aroylhydrazones
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A new metal complexes have been synthesized by a reaction of metal compounds contained Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with two kinds of ligands that are 2-carboxy benzaldehyde 4-methylbenzoylhydrazone(CBMH) and 2-carboxy benzaldehyde picolinoyl hydrazine (CBPH), the ligands (CBMH and CBPH) were prepared by condensation of 2-carboxy benzaldehyde with 4-methylbenzoyl hydrazide or picolinoyl hydrazide, respectively. In fact, complexes[M(L-H)2]. xH2O were characterized by elemental analysis, molar conductance, magnetic susceptibility, and spectral measurements (UV-Vis, IR,). The hydrazones CBMH and CBPH act as monobasic tridentate ligands, in all their complexes. The ligand CBMH coordinated to the metal ions through the azomethine nitrogen, the carboxyl group oxygen, and the amide carbonyl group oxygen atoms, while the ligand CBPH coordinated through the carboxyl group oxygen, the azomethine nitrogen, and the pyridine ring nitrogen atoms. Physico-chemical studies suggest octahedral geometry for all metal(II) complexes.
- Al-Daher, Abdul Ghany M.,Alfares, Amenah A.,Alnuaimy, Lana A.
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p. 271 - 278
(2022/01/22)
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- Structural and photophysical properties of lanthanide complexes with N'- (2- methoxybenzylidene) - 2-pyridinecarbohydrazide Schiff base ligand: Catalyzed oxidation of anilines with hydrogen peroxide
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Several lanthanide (III) complexes {Ln: La, 1; Sm, 2; Eu, 3; Gd, 4; Tb, 5; Dy, 6} with the Schiff base ligand, N'-?(2-?methoxybenzylidene)?-?2-pyridinecarbohydrazide, L, have been synthesized. These complexes having general formula LaL(NO3)3.xH2O and LnL2(NO3)3.xH2O, and the ligand L have been characterized by elemental analysis, spectral analysis (IR, 1H and 13C NMR), molar conductivity and thermogravimetric analysis. In the proposed structure of complex 1, La(III) ion is ten coordinate. Six coordination sites are satisfied by three bi-dentate nitrate ions, one site is occupied by H2O and the remaining three positions are occupied by ONO belonging to one neutral L. In contrast the lanthanide ion in the proposed structures of complexes 2 - 6, is twelve coordinated by two three bi-dentate ONO L and three bi-dentate nitrate anions. The photophysical properties of L and 1 – 6 in DMF solution have been investigated and reported. Complexes 1 - 6 catalyze the oxidation of aniline 1a and its derivatives 1b - 1 g using H2O2 as an oxygen source at an ambient conditions. Aniline is selectively converted to nitroso-benzene in the presence of complexes 2 and 3. Complexes 4 – 6 gave mixtures of nitrozo- and azoxybenzenes. With complex 1 a mixture of nitroso-, azoxy- and azobenzenes were obtained. Among the substrates tested, the best result was obtained in the case of 1e with 78.6% conversion and 100% selectivity for the nitroso-benzene in the presence of 4 as a catalyst.
- Taha, Ziyad A.,Hijazi, Ahmed K.
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- N-acylhydrazones confer inhibitory efficacy against New Delhi metallo-β-lactamase-1
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The expression of β-lactamases, especially metallo-β-lactamases (MβLs) in bacteria is one of the main causes of drug resistance. In this work, an effective N-acylhydrazone scaffold as MβL inhibitor was constructed and characterized. The biological activity assays indicated that the synthesized N-acylhydrazones 1–11 preferentially inhibited MβL NDM-1, and 1 was found to be the most effective inhibitor with an IC50 of 1.2 μM. Analysis of IC50 data revealed a structure–activity relationship, which is that the pyridine and hydroxylbenzene substituents at 2-position improved inhibition of the compounds on NDM-1. ITC and enzyme kinetics assays suggested that it reversibly and competitively inhibited NDM-1 (Ki = 0.29 ± 0.05 μM). The synthesized N-acylhydrazones showed synergistic antibacterial activities with meropenem, reduced 4–16-fold MIC of meropenem on NDM-1- producing E. coli BL21 (DE3), while 1 restored 4-fold activity of meropenem on K. pneumonia expressing NDM-1 (NDM-K. pneumoniae). The mice experiments suggested that 1 combined meropenem to fight against NDM-K. pneumoniae infection in the spleen and liver. Cytotoxicity assays showed that 1 and 2 have low cytotoxicity. This study offered a new framework for the development of NDM-1 inhibitors.
- Gao, Han,Li, Jia-Qi,Kang, Peng-Wei,Chigan, Jia-Zhu,Wang, Huan,Liu, Lu,Xu, Yin-Sui,Zhai, Le,Yang, Ke-Wu
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- Pleuromutilin derivative with 1, 3, 4-oxadiazole side chain and preparation and application thereof
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The invention belongs to the field of medicinal chemistry, and particularly relates to a pleuromutilin derivative with a 1, 3, 4-oxadiazole side chain and preparation and application thereof The pleuromutilin derivative with the 1, 3, 4-oxadiazole side chain is a compound shown in a formula 2 or a pharmaceutically acceptable salt thereof, and a solvent compound, an enantiomer, a diastereoisomer and a tautomer of the compound shown in the formula 2 or the pharmaceutically acceptable salt thereof or a mixture of the solvent compound, the enantiomer, the diastereoisomer and the tautomer in any proportion, including a racemic mixture. The pleuromutilin derivative has good antibacterial activity, is especially suitable for being used as a novel antibacterial agent for systemic system infection of animals or human beings, and has good water solubility.
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Paragraph 0055-0056; 0070; 0090; 0093; 0095; 0102
(2021/07/24)
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- A remarkable energy barrier for spin reversal in a field induced dinuclear ytterbium single molecule magnet
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A dinuclear ytterbium complex has been designed with a strong ligand field in equatorial positions. Magnetic studies reveal the presence of easy-axis anisotropy and field induced slow relaxation of magnetization with a remarkable energy barrier,Ueff= 53.58 cm?1, the highest value reported for any Yb-based SMMs to date. Furthermore, theab initiocalculations disclose the importance of a weak axial ligand field to design high-performance Yb-based SMMs.
- Konar, Sanjit,Mondal, Arpan
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supporting information
p. 13666 - 13670
(2021/10/19)
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- Design, synthesis, in vitro and in vivo evaluation against MRSA and molecular docking studies of novel pleuromutilin derivatives bearing 1, 3, 4-oxadiazole linker
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A class of pleuromutilin derivatives containing 1, 3, 4-oxadiazole were designed and synthesized as potential antibacterial agents against Methicillin-resistant staphylococcus aureus (MRSA). The ultrasound-assisted reaction was proposed as a green chemistry method to synthesize 1, 3, 4-oxadiazole derivatives (intermediates 85–110). Among these pleuromutilin derivatives, compound 133 was found to be the strongest antibacterial derivative against MRSA (MIC = 0.125 μg/mL). Furthermore, the result of the time-kill curves displayed that compound 133 could inhibit the growth of MRSA in vitro quickly (- 4.36 log10 CFU/mL reduction). Then, compound 133 (- 1.82 log10 CFU/mL) displayed superior in vivo antibacterial efficacy than tiamulin (- 0.82 log10 CFU/mL) in reducing MRSA load in mice thigh model. Besides, compound 133 exhibited low cytotoxicity to RAW 264.7 cells. Molecular docking studies revealed that compound 133 was successfully localized in the binding pocket of 50S ribosomal subunit (ΔGb = -10.50 kcal/mol). The results indicated that these pleuromutilin derivatives containing 1, 3, 4-oxadiazole might be further developed into novel antibiotics against MRSA.
- Liu, Jie,Zhang, Guang-Yu,Zhang, Zhe,Li, Bo,Chai, Fei,Wang, Qi,Zhou, Zi-Dan,Xu, Ling-Ling,Wang, Shou-Kai,Jin, Zhen,Tang, You-Zhi
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- Design, Synthesis, and Herbicidal Activity of Thioether Containing 1,2,4-Triazole Schiff Bases as Transketolase Inhibitors
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Transketolase (TK) represents a potential target for novel herbicide development. To discover novel TK inhibitors with potency against resistant weeds, 36 thioether compounds containing 1,2,4-triazole Schiff bases were designed and synthesized for herbicidal activity evaluation. The results demonstrated that compounds 5av and 5aw provided excellent weed control with inhibition of over 90% against the tested weeds, even at concentrations as low as 100 mg/L in vitro. In addition, compounds 5av and 5aw exhibited higher postemergence herbicidal activity than all of the positive controls against the tested weeds at 50-90 g [active ingredient (ai)]/ha in a greenhouse, while being safe for crops of maize and wheat at 90 g (ai)/ha. Fluorescent binding experiments of At TK indicated that compounds 5av and 5aw had strong TK inhibitory activity and could tightly bind with the enzyme At TK. Also, molecular docking analyses revealed that the structures of compounds 5av and 5aw were suitable for TK inhibitory activity. Taken together, these results suggested that compounds 5av and 5aw were promising herbicide candidates for weed control in wheat and maize fields targeting TK.
- Wang, Yan-En,Yang, Dongchen,Huo, Jingqian,Chen, Lai,Kang, Zhanhai,Mao, Jianyou,Zhang, Jinlin
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p. 11773 - 11780
(2021/10/20)
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- Acylhydrazone compound as well as pharmaceutical composition and application thereof
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The invention relates to an acylhydrazone compound as well as a pharmaceutical composition and application thereof. According to the main technical scheme, the structure of the acylhydrazone compoundis as shown in one of a general formula (I), a general formula (II) and a general formula (III); wherein V1, W1, X1, Y1 and Z1 are independently selected from one of the following groups: N and C-R13;A2, B2, D2, E2, G2, J2, L2, T3, V3, U3, W3, X3, Y3 and Z3 are independently selected from one of the following groups: N and C-R4; R11, R21 and R31 are independently selected from one of the following groups: hydrogen-H and a first chain alkyl. The pharmaceutical composition comprises the acylhydrazone compound. The method is mainly used for designing the acylhydrazone compound. The acylhydrazonecompound and the pharmaceutical composition taking the acylhydrazone compound as an active ingredient can be used as an acetylcholin esterase AChE inhibitor and used for preparing a medicine for treating Alzheimer's disease.
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Paragraph 0121; 0123; 0128-0129
(2020/11/25)
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- Synthesis and trypanocidal activity of novel pyridinyl-1,3,4-thiadiazole derivatives
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Herein, we present the design, synthesis and trypanocidal evaluation of sixteen new 1,3,4-thiadiazole derivatives from N-aminobenzyl or N-arylhydrazone series. All derivatives were assayed against the trypomastigote form of Trypanosoma cruzi, showing IC50 values ranging from 3 to 226 μM, and a better trypanocidal profile was demonstrated for the 1,3,4-thiadiazole-N-arylhydrazones (3a-g). In this series, the 2-pyridinyl fragment bound to the imine subunit of the hydrazine moiety presented pharmacophoric behavior for trypanocidal activity. Compounds 2a, 11a and 3e presented remarkable activity and excellent selectivity indexes. Compound 2a was also active against the intracellular amastigote form of T. cruzi. Moreover, its corresponding hydrochloride, compound 11a, showed the most promising profile, producing phenotypic changes similar to those caused by posaconazole, a well-known inhibitor of sterol biosynthesis. Thus, 1,3,4-thiadiazole derivative 11a could be considered a good prototype for the development of new drug candidates for Chagas disease therapy.
- Barbosa, Juliana M. C.,Bernardino, Patrícia,Decoté-Ricardo, Débora,Fraga, Carlos A. M.,Freitas, Rosana H. C. N.,Melo, Tatiana G.,Salom?o, Kelly,Sueth-Santiago, Vitor,Wardell, James L.,Wardell, Solange M. S. V.,da Silva, Edson F.
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- Discovery of [1,2,4]triazole derivatives as new metallo-β-lactamase inhibitors
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The emergence and spread of metallo-β-lactamase (MBL)-mediated resistance to β-lactam antibacterials has already threatened the global public health. A clinically useful MBL inhibitor that can reverse β-lactam resistance has not been established yet. We here report a series of [1,2,4]triazole derivatives and analogs, which displayed inhibition to the clinically relevant subclass B1 (Verona integron-encoded MBL-2) VIM-2. 3-(4-Bromophenyl)-6,7-dihydro-5H-[1,2,4]triazolo [3,4-b][1,3]thiazine (5l) manifested the most potent inhibition with an IC50 (half-maximal inhibitory concentration) value of 38.36 μM. Investigations of 5l against other B1 MBLs and the serine β-lactamases (SBLs) revealed the selectivity to VIM-2. Molecular docking analyses suggested that 5l bound to the VIM-2 active site via the triazole involving zinc coordination and made hydrophobic interactions with the residues Phe61 and Tyr67 on the flexible L1 loop. This work provided new triazole-based MBL inhibitors and may aid efforts to develop new types of inhibitors combating MBL-mediated resistance.
- Yuan, Chen,Yan, Jie,Song, Chen,Yang, Fan,Li, Chao,Wang, Cheng,Su, Huiling,Chen, Wei,Wang, Lijiao,Wang, Zhouyu,Qian, Shan,Yang, Lingling
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- Design, synthesis, and biological evaluation of new challenging thalidomide analogs as potential anticancer immunomodulatory agents
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Thalidomide and its analogs are immunomodulatory drugs that inhibit the production of certain inflammatory mediators associated with cancer. In the present work, a new series of thalidomide analogs was designed and synthesized to obtain new effective antitumor immunomodulatory agents. The synthesized compounds were evaluated for their cytotoxic activities against a panel of four cancer cell lines (HepG-2, HCT-116, PC3 and MCF-7). Compounds 33h, 33i, 42f and 42h showed strong potencies against all tested cell lines with IC50 values ranging from 14.63 to 49.90 μM comparable to that of thalidomide (IC50 values ranging from 32.12 to 76.91 μM). The most active compounds were further evaluated for their in vitro immunomodulatory activities via estimation of human tumor necrosis factor alpha (TNF-α), human caspase-8 (CASP8), human vascular endothelial growth factor (VEGF), and nuclear factor kappa-B P65 (NF-κB P65) in HCT-116 cells. Thalidomide was used as a positive control. Compounds 33h and 42f showed a significant reduction in TNF-α. Furthermore, compounds 33i and 42f exhibited significant elevation in CASP8 levels. Compounds 33i and 42f inhibited VEGF. In addition, compound 42f showed significant decrease in levels of NF-κB p65. Moreover, apoptosis and cell cycle tests of the most active compound 42f, were performed. The results indicated that compound 42f significantly induce apoptosis in HCT-116 cells and arrest cell cycle at the G2/M phase.
- El-Zahabi, Mohamed Ayman,Sakr, Helmy,El-Adl, Khaled.,Zayed, Mohamed,Abdelraheem, Adel S.,Eissa, Sally I.,Elkady, Hazem,Eissa, Ibrahim H.
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- 4-Amino-1,2,4-triazole-3-thione-derived Schiff bases as metallo-β-lactamase inhibitors
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Resistance to β-lactam antibiotics in Gram-negatives producing metallo-β-lactamases (MBLs) represents a major medical threat and there is an extremely urgent need to develop clinically useful inhibitors. We previously reported the original binding mode of 5-substituted-4-amino/H-1,2,4-triazole-3-thione compounds in the catalytic site of an MBL. Moreover, we showed that, although moderately potent, they represented a promising basis for the development of broad-spectrum MBL inhibitors. Here, we synthesized and characterized a large number of 4-amino-1,2,4-triazole-3-thione-derived Schiff bases. Compared to the previous series, the presence of an aryl moiety at position 4 afforded an average 10-fold increase in potency. Among 90 synthetic compounds, more than half inhibited at least one of the six tested MBLs (L1, VIM-4, VIM-2, NDM-1, IMP-1, CphA) with Ki values in the μM to sub-μM range. Several were broad-spectrum inhibitors, also inhibiting the most clinically relevant VIM-2 and NDM-1. Active compounds generally contained halogenated, bicyclic aryl or phenolic moieties at position 5, and one substituent among o-benzoic, 2,4-dihydroxyphenyl, p-benzyloxyphenyl or 3-(m-benzoyl)-phenyl at position 4. The crystallographic structure of VIM-2 in complex with an inhibitor showed the expected binding between the triazole-thione moiety and the dinuclear centre and also revealed a network of interactions involving Phe61, Tyr67, Trp87 and the conserved Asn233. Microbiological analysis suggested that the potentiation activity of the compounds was limited by poor outer membrane penetration or efflux. This was supported by the ability of one compound to restore the susceptibility of an NDM-1-producing E. coli clinical strain toward several β-lactams in the presence only of a sub-inhibitory concentration of colistin, a permeabilizing agent. Finally, some compounds were tested against the structurally similar di-zinc human glyoxalase II and found weaker inhibitors of the latter enzyme, thus showing a promising selectivity towards MBLs.
- Baud, Damien,Bebrone, Carine,Becker, Katja,Benvenuti, Manuela,Cerboni, Giulia,Chelini, Giulia,Cutolo, Giuliano,De Luca, Filomena,Docquier, Jean-Denis,Feller, Georges,Fischer, Marina,Galleni, Moreno,Gavara, Laurent,Gresh, Nohad,Kwapien, Karolina,Legru, Alice,Mangani, Stefano,Mercuri, Paola,Pozzi, Cecilia,Sannio, Filomena,Sevaille, Laurent,Tanfoni, Silvia,Verdirosa, Federica,Berthomieu, Dorothée,Bestgen, Beno?t,Frère, Jean-Marie,Hernandez, Jean-Fran?ois
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- Synthesis and structural study of some N-acyl-4-allylsemicarbazides and the product of their cyclization with a potential antimicrobial activity
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In this paper semicarbazide (2a-2h) and 1,2,4-trazole (3a-3h) derivatives with allyl group were synthesized. All compounds were tested in vitro for their antimicrobial activity showing different activity to E. coli, S. aureus, S. epidermidis, M. smegmatis, M. phlei and M. tuberculosis H37Ra. The antimicrobial activity is showed 2g against S. epidermidis, 3g against E. coli and S. epidermidis and 3h against E. coli. The crystal structure of determinations of 2b, 2d, 3b, 3c and 3e were undertaken in order to confirm the synthesis pathway and identification of their tautomeric forms in the crystalline state. Theoretical calculations showed that the physico-chemicals (logP) and electronic properties (MEP distribution, energy localization of HOMO and LUMO orbitals) are related to observed antimicrobial activity of investigated compounds. The molecular docking study carried out for the most active against M. tuberculosis compound 3b using the M. tuberculosis cytochrome P450 CYP121 showed that this compound binds to the active site of P450 by hydrogen bonds via water molecule with the amino acid residue of Met86A and molecule of hem.
- Drozd, Monika,Ginalska, Grazyna,Karczmarzyk, Zbigniew,Kowalczuk, Dorota,Morawiak, Maja,Pitucha, Monika,Swatko-Ossor, Marta,Urbanczyk-Lipkowska, Zofia,Wysocki, Waldemar
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- Design, synthesis and biological evaluation of novel copper-chelating acetylcholinesterase inhibitors with pyridine N-benzylpiperidine fragments
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Cholinergic depletion is the direct cause of disability and dementia among AD patients. AChE is a classical and key target of cholinergic disorders. Some new inhibitors of AChE combining pyridine, acylhydrazone and N-benzylpiperidine fragments were developed in this work. The hit structure was optimized to yield the compound 21 with an IC50 value of 6.62 nM against AChE, while almost no inhibitory effect against BChE. ADMET predictions and PAMPA permeability evaluation showed good drug-like property. The higher activity with an intermediate alkyl chain substitution indicates a new binding mode of inhibitor with AChE. This finding provides new insights into the binding mechanism and is helpful for discovery of novel high-activity AChE inhibitors.
- Zhou, Yeheng,Sun, Wei,Peng, Jiale,Yan, Hui,Zhang, Li,Liu, Xingyong,Zuo, Zhili
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supporting information
(2019/10/08)
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- TBSOTf-promoted versatile N-formylation using DMF at room temperature
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Hydrazides and amines were N-formylated by DMF in the presence of tert-butyldimethylsilyl triflate (TBSOTf) at room temperature, in good to excellent yields.
- Sakurai, Masayoshi,Kawakami, Rina,Kihara, Nobuhiro
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supporting information
p. 1291 - 1294
(2019/04/10)
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- ATF6 INHIBITORS AND USES THEREOF
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Compounds as inhibitors of Activating Transcription Factor 6 (ATF6) are provided. The compounds may find use as therapeutic agents for the treatment of diseases or disorders mediated by ATF6 and may find particular use in the treatment of viral infections, neurodegenerative diseases, vascular diseases, or cancer.
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Paragraph 0506; 0505
(2019/10/29)
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- Synthesis of novel indole derivatives containing double 1,3,4-oxadiazole moiety as efficient bactericides against phytopathogenic bacterium Xanthomonas oryzae
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Abstract: A series of novel indole derivatives containing double 1,3,4-oxadiazole moiety was designed, synthesized and evaluated for their antibacterial activities in vitro. These compounds were fully characterized by 1H NMR, 13C NMR, and HRMS. Bioassay results indicated that most of title compounds exhibited excellent antibacterial activities against rice bacterial pathogen Xanthomonas oryzae (Xoo). For example, compounds 7d, 7h, 7i, 7j, 7k, 7l and 7m had the half-maximal effective concentration (EC50) values of 52.31, 54.12, 40.65, 38.80, 51.13, 52.75 and 50.66?μg/mL, respectively, which was better than that of commercial product bismerthiazol (BMT) (85.18?μg/mL). The experimental results proved that indole derivatives bearing double 1,3,4-oxadiazole unit are promising candidates for the development of new agricultural bactericides against pathogenic bacterium Xoo. Graphical abstract: [Figure not available: see fulltext.].
- Tian, Kun,Li, Xiao-Qin,Zhang, Li,Gan, Yi-Yuan,Meng, Jiao,Wu, Shou-Qun,Wan, Jin-Lin,Xu, Yang,Cai, Chao-Ting,Ouyang, Gui-Ping,Wang, Zhen-Chao
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-
- Oxadiazole derivative and application thereof
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The invention provides an oxadiazole derivative and application thereof. The oxadiazole derivative provided by the invention uses oxadiazole and pyridine as electron acceptors and uses carbazole as anelectron donor to form molecules with different steric hindrances and different conjugated degrees by different connection modes. The molecules have higher triplet state energy level, have both charge and hole transport functions, and can be used as blue or green main body type materials in the field of organic electroluminescence. When the material as a main body is applied to a blue light organic device using FIrpic as an object, a light-emitting device with an external quantum efficiency being 14.6 to 20.8 percent can be obtained. When the material as the main body is applied into a greenorganic light-emitting device using Ir(ppy)3 as the object, a light-emitting device with the external quantum efficiency being 10.6 to 21.8 percent can be obtained.
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- Copper-Promoted Oxidative Intramolecular C–H Amination of Hydrazones to Synthesize 1H-Indazoles and 1H-Pyrazoles Using a Cleavable Directing Group
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A facile and efficient synthesis of 1H-indazoles and 1H-pyrazoles through a copper-promoted oxidative intramolecular C–H amination of hydrazones using a cleavable directing group was developed. This reaction is characterized by its mild conditions, operational simplicity, readily available reagents, and excellent yields. A tentative mechanism for Cu-mediated C–H oxidative amination was proposed.
- Zhang, Guofu,Fan, Qiankun,Zhao, Yiyong,Ding, Chengrong
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p. 5801 - 5806
(2019/08/02)
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- Design of a coumarinyl-picolinoyl hydrazide Schiff base for the fluorescence turn-on-off sequential sensing of Al3+ and nitroaromatics, and electronic device fabrication
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(E)-N′-((7-Hydroxy-4-methyl-2-oxo-2H-chromen-8-yl)methylene)picolinohydrazide (H-CPh), a greenish yellow emitter in the solid state, aggregates in DMSO solution upon increasing the percentage of water (>50%) and the maximized emission intensity was reached at 90% water-DMSO medium. Upon excitation at 400 nm in pure aquatic medium (HEPES buffer, pH 7.2) H-CPh shows fluorescence sensitivity to Al3+ (λem, 470 nm) and forms a 1:1 complex, [(CPh)Al(OH)(H2O)]NO3, with a limit of detection (LOD) of 6.99 nM. The complex, [(CPh)Al(OH)(H2O)]NO3 shows sensitivity to nitroaromatics by quenching the strong emission of the fluorogenic complex and the LODs are: 2,4-dinitrophenol (DNP), 1.67 μM and 2,4,6-trinitrophenol (TNP) 0.99 μM. The H-CPh is electronically a semiconductor and the experimental (2.78 eV) and the DFT derived (2.75 eV) band gaps are comparable. The H-CPh forms a Schottky diode and its photoconductivity (19.98 × 10-4 S m-1) is three times higher than the dark phase conductivity (6.42 × 10-4 S m-1).
- Purkait, Rakesh,Dey, Arka,Dey, Sunanda,Ray, Partha Pratim,Sinha, Chittaranjan
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p. 14979 - 14990
(2019/09/30)
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- Recognition of Al3+ through the off-on mechanism as a proficient driving force for the hydrolysis of BODIPY conjugated Schiff base and its application in bio-imaging
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Two new BODIPY azine bearing quinoline and pyrazine attached Schiff base chemosensors (R1 and R2) have been synthesized and applied for the detection of Al3+ in CH3CN/H2O medium. Intramolecular hydrogen bonding makes both the sensors rigid and helps to encapsulate Al3+ in the cavity. The pink colour of R1 and R2 has been changed to green fluorescent upon excess addition of Al3+ which is only because of the hydrolysis of imine bond to regenerate compound 8. Another nitrogen atom present in quinoline and in pyrazine moiety made R1 and R2 more efficient in sensing of Al3+ ion compare to R1D, R2B and R2D. Cell viability and fluorescence microscopic experiments showed that the chemosensors are cytocompatible and can be used as an effective fluorescent probe for detecting Al3+ ion in the living cell.
- Kashyap, Kumari Somlata,Kumar, Ashish,Hira, Sumit Kumar,Dey, Swapan
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- Synthesis and anti-endoplasmic reticulum stress activity of N-substituted-2-arylcarbonylhydrazinecarbothioamides
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Misfolded or unfolded proteins are accumulated in lumen of endoplasmic reticulum (ER) in ER stress condition. It has been implicated in many pathological conditions such as Alzheimer’s disease, diabetic retinopathy, atherosclerosis, β-cell apoptosis and lung inflammation. We found a series of N-substituted-2-arylcarbonylhydrazinecarbothioamides to potently decrease ER stress signal, showing up to almost 300-fold better activity than 1-hydroxynaphthoic acid and tauro-ursodesoxycholic acid, positive controls, respectively. Structure?activity relationship (SAR) study showed that 2-arylcarbonyl moiety is critical for the activity of the hydrazinecarbothioamide analogues and side chains tethering on thioamide moiety were relatively insensitive to the activity. Some analogues were found to consistently exert the potency under more physiologically relevant condition where ER stress was induced by palmitic acid. ER stress markers such as CHOP and phosphorylated eIF2α and PERK were accordingly decreased in western blotting upon treatment of compound 4h. Potential ER stress inhibitory activity and novel structures could provide a novel platform for new chemical chaperone and therapy for protein misfolding diseases.
- Choi, Hoon,Yun, Wheesahng,Lee, Jung-hun,Jang, Seoul,Park, Sang Won,Kim, Dong Hwan,Seon, Kyoung Pyo,Hyun, Jung-mi,Jeong, Kwiwan,Ku, Jin-mo,Nam, Tae-gyu
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p. 2142 - 2152
(2019/11/03)
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- Synthesis, in vitro screening and docking studies of new thiosemicarbazide derivatives as antitubercular agents
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A series of thiosemicarbazide derivatives was designed and synthesized by reaction of carboxylic acid hydrazide with isothiocyanates. The molecular structures of the investigated thiosemicarbazides were confirmed and characterized by spectroscopic analysis. The conformational preference of carbonylthiosemicarbazide chain and intra- and intermolecular interactions in the crystalline state were characterized using X-ray analysis. The antituberculosis activity of the target compounds were tested in vitro against four Mycobacterium strains: M. H37Ra, M. phlei, M. smegmatis, M. timereck. The most active compounds were those with 2-pyridine ring. They exhibited lower minimal inhibitory concentration (MIC) values in the range 7.81–31.25 μg/mL in comparison to the other isomers. Compound 5 had activity against M. smegmatis at a concentration of 7.81 μg/mL whereas compound 2 had activity against all tested strains at a concentration of 15.625 μg/mL. The molecular docking studies were performed for investigated compounds using the Mycobacterium tuberculosis glutamine synthetase MtGS as their molecular target.
- Pitucha, Monika,Karczmarzyk, Zbigniew,Swatko-Ossor, Marta,Wysocki, Waldemar,Wos, Maciej,Chudzik, Kamil,Ginalska, Grazyna,Fruzinski, Andrzej
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- ''One-pot method'' for synthesis of capsule-like coordination compound containing Schiff base structural unit, and preparation method and application thereof
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The invention belongs to the technical field of preparation of complexes, and relates to a ''one-pot method'' for synthesis of a capsule-like complex containing a Schiff base structural unit and a preparation method and application thereof. Firstly, a three-arm ligand L as shown in the formula I is prepared, and the structural formula is as shown in the specification; and then, a capsule-like complex is obtained by the use of the three-arm ligand L and AgBF4, and the molecular formula is C91H100Ag5N30OS6Cl12F20B5 and the chemical formula is [Ag5(C84H90N30S6)].5(BF4).4(CHCl3).C3H6O. The capsule-like complex is applied to fluorescence recognition and enrichment purification of metal ions.
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Paragraph 0025; 0054; 0055
(2019/02/13)
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- NOVEL OXABOROLE ANALOGS AND USES THEREOF
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This application describes compounds, compositions, and methods which are useful in treating, preventing, inhibiting, ameliorating, or eradicating the pathology and/or symptomology of a disease caused by a parasite.
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Paragraph 0220
(2018/09/21)
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- 3. 6 - Disubstituted [1, 2, 4] triazolo [3, 4 - b] [1, 3, 4] thiadiazole compound and use thereof
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The invention discloses 3,6-disubstituted[1,2,4]triazolyl[3,4-b][1,3,4]thiadiazole compounds represented by general formula (I), and pharmaceutically acceptable salts or pharmaceutically acceptable solvates thereof. The compounds can be used as a transpeptidase SrtA inhibitor of Staphylococcus aureus, Bacillus pyogenes, Bacillus anthracis, Streptococcus pneumoniae and other Gram-positive bacteria, and can be used to prepare drugs for treating pathogen infection diseases with the transpeptidase SrtA of the Gram-positive bacteria, such as Staphylococcus aureus, Bacillus pyogenes, Bacillus anthracis and Streptococcus pneumoniae as target. The compounds avoid selection pressure induced drug resistance of pathogens to a certain degree, and mitigate threat of continuous drug-resistant pathogens to the health of human.
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Paragraph 0072; 0073
(2018/11/22)
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- With piezochromic characteristic ion iridium complex and its preparation method and application
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The invention relates to an ionic type iridium complex with piezochromic characteristic as well as a preparation method and application thereof and in particular relates to an ionic type iridium complex (III) based on 1,3,4-oxadiazole N^N auxiliary ligand, wherein a structural formula of the ionic type iridium complex is shown as a formula (I) or a formula (II) in the specification. Synthesis steps of the ionic type iridium complex are simple, synthesis conditions are mild, and luminescence of an organic luminophor in a solid state is changed by virtue of external factors of heat, light, electricity, pressure and the like, wherein the phenomenon that the luminescence of the solid organic luminophor is changed by adopting a pressure or mechanical grinding manner is called as a piezochromic phenomenon. A piezochromic material has unique emitting colour changing and reversing properties, so that the ionic type iridium complex has great potential in application of record, data storage, sensors and the like.
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Paragraph 0045; 0047
(2017/06/30)
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- Synthesis and Biological Activity of Anthranilic Diamide Derivatives Incorporating 1,3,4-oxadiazole or Nitrogen-containing Saturated Heterocyclic Moieties
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A series of novel anthranilic diamide derivatives incorporating 1,3,4-oxadiazole or nitrogen-containing saturated heterocyclic moieties were synthesized, characterized, and evaluated for bacteriostatic activity against three phytopathogenic bacteria Xanthomonas oryzae pv. Oryzae (Xoo), Xanthomonas axonopodis pv. Citri (Xac), Ralstonia solanacearum (R. solanacearum). The preliminary biological results indicated that most compounds exhibit bacteriostatic activity against three phytopathogenic bacteria. Among these compounds, compounds 6g, 6f, and 6i displayed better antibacterial activity. In the test with concentration of 200 μg/mL, antibacterial activity of compound 6i and 6j was 96%. In particular, the bacteriostatic activity displayed by compound 6h against Xoo is similar to the one displayed by commercial drug bismerthiazol.
- Zhou, Wen-Juan,Zhang, Li,Xiao, Wei,Chen, He-Ju,Wu, Wen-Neng,Ouyang, Gui-Ping
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p. 1423 - 1429
(2017/03/27)
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- 1,2,4-Triazole-3-thione Compounds as Inhibitors of Dizinc Metallo-β-lactamases
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Metallo-β-lactamases (MBLs) cause resistance of Gram-negative bacteria to β-lactam antibiotics and are of serious concern, because they can inactivate the last-resort carbapenems and because MBL inhibitors of clinical value are still lacking. We previously identified the original binding mode of 4-amino-2,4-dihydro-5-(2-methylphenyl)-3H-1,2,4-triazole-3-thione (compound IIIA) within the dizinc active site of the L1 MBL. Herein we present the crystallographic structure of a complex of L1 with the corresponding non-amino compound IIIB (1,2-dihydro-5-(2-methylphenyl)-3H-1,2,4-triazole-3-thione). Unexpectedly, the binding mode of IIIB was similar but reverse to that of IIIA. The 3 D structures suggested that the triazole–thione scaffold was suitable to bind to the catalytic site of dizinc metalloenzymes. On the basis of these results, we synthesized 54 analogues of IIIA or IIIB. Nineteen showed IC50 values in the micromolar range toward at least one of five representative MBLs (i.e., L1, VIM-4, VIM-2, NDM-1, and IMP-1). Five of these exhibited a significant inhibition of at least four enzymes, including NDM-1, VIM-2, and IMP-1. Active compounds mainly featured either halogen or bulky bicyclic aryl substituents. Finally, some compounds were also tested on several microbial dinuclear zinc-dependent hydrolases belonging to the MBL-fold superfamily (i.e., endonucleases and glyoxalase II) to explore their activity toward structurally similar but functionally distinct enzymes. Whereas the bacterial tRNases were not inhibited, the best IC50 values toward plasmodial glyoxalase II were in the 10 μm range.
- Sevaille, Laurent,Gavara, Laurent,Bebrone, Carine,De Luca, Filomena,Nauton, Lionel,Achard, Maud,Mercuri, Paola,Tanfoni, Silvia,Borgianni, Luisa,Guyon, Carole,Lonjon, Pauline,Turan-Zitouni, Gülhan,Dzieciolowski, Julia,Becker, Katja,Bénard, Lionel,Condon, Ciaran,Maillard, Ludovic,Martinez, Jean,Frère, Jean-Marie,Dideberg, Otto,Galleni, Moreno,Docquier, Jean-Denis,Hernandez, Jean-Fran?ois
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p. 972 - 985
(2017/06/27)
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- Method for preparing aminopyridine from methylpyridine, and purifying method of aminopyridine
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The invention relates to the field of organic synthesis, and concretely relates to a method for preparing aminopyridine from methylpyridine, and a purifying method of aminopyridine. Crude aminopyridine is prepared from corresponding methylpyridine through oxidation, esterification, hydrazinolysis and rearrangement reactions, the reaction yield of every step is high, and a post-treatment technology is easy to industrially operate; in the oxidation reaction, beta-cyclodextrin is used as a catalyst, so the conversion rate of the oxidation reaction is increased, and the generation of byproducts is reduced; and anhydrous ethanol and an alkane reagent are used to re-crystallize the crude aminopyridine, and a decolorizing agent is combined, and the purity of the final product reaches 98% or more; and the purifying method has the advantages of simplicity, easiness in operation, easily available raw materials, and suitableness for industrial production.
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- Syntheses, Crystal Structures, and Spectral Characterization of Six Novel Benzimidazolyl Substituted Triaryltriazoles
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Six new benzimidazolyl substituted triaryltriazoles, 3-(2-pyridyl)-4-(p-R-phenyl)-5-(2-benzimidazolyl)-1,2,4-triazoles (L1: R?=?OCH3; L2: R?=?CH3; L3: R?=?H; L4: R?=?Br; L5: R?=?Cl; L6: R?=?F) were successfully synthesized. Yield of L1–6 is in the range from 61 to 76%. The compounds L1–6 were characterized by UV–vis, FTIR, 1H-NMR, ESI-MS spectra, and elemental analysis. Additionally, the absolute configurations of L1–5 were determined by single crystal X-ray crystallography.
- Zhou, Yong-Fei,Zhang, Shi-Pei,Feng, Zhe,Shen, Xuan,Zhu, Dun-Ru
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p. 2773 - 2780
(2017/09/26)
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- METHODS FOR INDUCING BIOORTHOGONAL REACTIVITY
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A method for catalytically converting a dihydrotetrazine 1 into a tetrazine 2, wherein one R group on the dihydrotetrazine 1 is a substituted or unsubstituted aryi, heteroaryl, alkyl, alkenyl, alkynyl, carbonyl, or heteroatom-containing group, and the other R group is selected from the group consisting of H and substituted or unsubstituted aryl, heteroaryl, alkyl, alkenyl, alkynyl, carbonyl,-or heteroatom-containing groups; 1, 2 wherein the method comprises oxidizing dihydrotetrazine 1 in a reaction medium in the presence of a catalyst and a stoichiometric oxidant.
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Page/Page column 37-38
(2017/07/06)
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- ALIPHATIC-AROMATIC HETEROCYCLIC COMPOUNDS AND USES THEREOF IN METAL EXTRACTANT COMPOSITIONS
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The invention relates to an aliphatic-aromatic heterocyclic compound A which comprises at least two heterocyclic rings B and C, to a metal extractant composition E comprising this aliphatic-aromatic heterocyclic compound A and an organic acid D having at least one carboxylic, sulfonic, sulfuric, phosphinic, phosphonic, or phosphoric acid group, and to a process to extract one or more metals M selected from the group consisting of Ni and Co from an aqueous acidic leach solution PL comprising ions of at least one of the metals M, and further, at least one kind of further ions selected from the group consisting of Fe ions, Al ions, Cu ions, Mg ions, Mn ions, and also silicate anions, by mixing the solution PL with an extractant composition E, separating the organic and aqueous phases, and recovering the metal M from the separated organic phase.
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Paragraph 0158-0159
(2016/09/26)
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- Vanadium–Schiff base complex-functionalized SBA-15 as a heterogeneous catalyst: synthesis, characterization and application in pharmaceutical sulfoxidation of sulfids
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VO2(picolinichydrazone) complex as a catalyst was stabilized on a SBA-15 mesoporous silica as a catalytic support by using (3-chloropropyl)triethoxysilane as a connector. SBA-15 is nanoporous and has a high ratio of surface area to volume. The immobilization of a metal–Schiff base complex to the surface area of SBA-15 can improve its catalytic effects by increasing the catalytic surface area. Unlike homogeneous catalysts, heterogeneous catalysts can be recovered and reused several times without any significant loss of catalytic activity. A vanadium–Schiff base complex-functionalized SBA-15 was synthesized by covalency connected by a pre-synthesised VO2(picolinichydrazone) complex to silanated SBA-15. The synthesized vanadium–Schiff base complex was characterized by proton nuclear magnetic resonance (1H NMR) spectroscopy, carbon nuclear magnetic resonance (13C NMR) spectroscopy and Fourier transform infrared spectroscopy (FT-IR), and the final V/SBA-15 was characterized by FT-IR, ultraviolet–visible spectrophotometry and X-ray powder diffraction. The morphology of V/SBA-15 was also obtained by scanning electron microscopy and transmission electron microscopy. The catalytic effect was examined by using V/SBA-15 as a heterogeneous catalyst in sulfoxidation reactions. The synthesis of modafinil and modafinic acid by pharmaceutical sulfoxidation of solfides was carried out and the effects of different solvents, reaction times and also recoverability and reusability of the heterogeneous catalyst were investigated. This catalyst showed high yield of sulfide conversion, stability and recyclability in the sulfoxidation of sulfides.
- Taghizadeh, Mohammad Javad,Karimi, Homman,Abandansari, Hamid Sadeghi
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p. 8201 - 8215
(2016/11/25)
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- Synthesis, antibacterial and antiproliferative potential of some new 1-pyridinecarbonyl-4-substituted thiosemicarbazide derivatives
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In this study, the antibacterial, cytotoxic and antiproliferative activities of novel thiosemicarbazide derivatives were assessed. Our results demonstrated that some of the novel compounds possess good antibacterial properties against Staphylococcus epidermidis, Streptococcus mutans and Streptococcussanguinis and are only slightly cytotoxic; thus, they exhibit an excellent therapeutic index, which is higher than that of ethacridine lactate. Moreover, our data showed that compounds 2 and 4 have an antiproliferative activity against human breast adenocarcinoma and human hepatocellular carcinoma cell lines. We expect that the novel thiosemicarbazide derivatives can be used as agents for treatment of dental caries and also for chemotherapy support.
- Pitucha, Monika,Wo?, Maciej,Miazga-Karska, Malgorzata,Klimek, Katarzyna,Miros?aw, Barbara,Pachuta-Stec, Anna,G?adysz, Agata,Ginalska, Grazyna
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p. 1666 - 1677
(2016/07/30)
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- Acylhydrazones as Widely Tunable Photoswitches
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Molecular photoswitches have attracted much attention in biological and materials contexts. Despite the fact that existing classes of these highly interesting functional molecules have been heavily investigated and optimized, distinct obstacles and inherent limitations remain. Considerable synthetic efforts and complex structure-property relationships render the development and exploitation of new photoswitch families difficult. Here, we focus our attention on acylhydrazones: a novel, yet underexploited class of photochromic molecules based on the imine structural motif. We optimized the synthesis of these potent photoswitches and prepared a library of over 40 compounds, bearing different substituents in all four crucial positions of the backbone fragment, and conducted a systematic study of their photochromic properties as a function of structural variation. This modular family of organic photoswitches offers a unique combination of properties and the compounds are easily prepared on large scales within hours, through an atom-economic synthesis, from commercially available starting materials. During our thorough spectroscopic investigations, we identified photoswitches covering a wide range of thermal half-lives of their (Z)-isomers, from short-lived T-type to thermally stable P-type derivatives. By proper substitution, excellent band separation between the absorbance maxima of (E)- and (Z)-isomers in the UV or visible region could be achieved. Our library furthermore includes notable examples of rare negative photochromic systems, and we show that acylhydrazones are highly fatigue resistant and exhibit good quantum yields.
- Van Dijken, Derk Jan,Kova?í?ek, Petr,Ihrig, Svante P.,Hecht, Stefan
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supporting information
p. 14982 - 14991
(2015/12/08)
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