104809-47-4Relevant articles and documents
Imaging and therapeutic applications of Zn(ii)-cryptolepine-curcumin molecular probes in cell apoptosis detection and photodynamic therapy
Huang, Xiao-Ling,Liang, Hong,Qin, Qi-Pin,Tan, Ming-Xiong,Wang, Zhen-Feng,Wei, Zu-Zhuang,Zou, Hua-Hong
, p. 3999 - 4002 (2020)
Novel red Zn(ii) complex-based fluorescent probes featuring cryptolepine-curcumin derivatives, namely, [Zn(BQ)Cl2] (BQ-Zn) and [Zn(BQ)(Cur)]Cl (BQCur-Zn), were developed for the simple and fluorescent label-free detection of apoptosis, an important biological process. The probes could synergistically promote mitochondrion-mediated apoptosis and enhance tumor therapeutic effects in vitro and vivo.
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Biehl,Li
, p. 602 (1966)
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The flavoenzyme azobenzene reductase AzoR from Escherichia coli binds roseoflavin mononucleotide (RoFMN) with high affinity and is less active in its RoFMN form
Langer, Simone,Nakanishi, Shinobu,Mathes, Tilo,Knaus, Tanja,Binter, Alexandra,Macheroux, Peter,Mase, Tomoko,Miyakawa, Takuya,Tanokura, Masaru,Mack, Matthias
, p. 4288 - 4295 (2013)
The Gram-positive bacterium Streptomyces davawensis is the only organism known to produce the antibiotic roseoflavin. Roseoflavin is a structural riboflavin analogue and is converted to the flavin mononucleotide (FMN) analogue roseoflavin mononucleotide (RoFMN) by flavokinase. FMN-dependent homodimeric azobenzene reductase (AzoR) (EC 1.7.1.6) from Escherichia coli was analyzed as a model enzyme. In vivo and in vitro experiments revealed that RoFMN binds to the AzoR apoenzyme with an even higher affinity compared to that of the "natural" cofactor FMN. Structural analysis (at a resolution of 1.07 A) revealed that RoFMN binding did not affect the overall topology of the enzyme and also did not interfere with dimerization of AzoR. The AzoR-RoFMN holoenzyme complex was found to be less active (30% of AzoR-FMN activity) in a standard assay. We provide evidence that the different physicochemical properties of RoFMN are responsible for its reduced cofactor activity.
Indicator Dyes and Catalytic Nanoparticles for Irreversible Visual Hydrogen Sensing
Smith, Michael E.,Stastny, Angela L.,Lynch, John A.,Yu, Zhao,Zhang, Peng,Heineman, William R.
, p. 10651 - 10658 (2020)
Using ultraviolet-visible (UV-vis) absorption spectroscopy, we have tested the reactivity of various indicator molecules combined with catalytic bimetallic gold-palladium nanoparticles (Au-Pd NPs) in solution for an irreversible and visual response to H2. Our aim was to identify the most suitable indicator/Au-Pd NP system for the future development of a thin, wearable, and visual H2 sensor for noninvasive monitoring of in vivo Mg-implant biodegradation in research and clinical settings with fast response time. The indicators studied were bromothymol blue, methyl red, and resazurin, and the reactions of each system with H2 in the presence of Au-Pd NPs caused visual and irreversible color changes that were concluded to proceed via redox processes. The resazurin/Au-Pd NP system was deemed best-suited for our research objectives because (1) this system had the fastest color change response to H2 at levels relevant to in vivo Mg-implant biodegradation compared to the other indicator/Au-Pd NP systems tested, (2) the observed redox chemistry with H2 followed well-understood reaction pathways reported in the literature, and (3) the redox products were nontoxic and appropriate for medical applications. Studying the effects of the concentrations of H2, Au-Pd NPs, and resazurin on the color change response time within the resazurin/Au-Pd NP system revealed that the H2-sensing elements can be optimized to achieve a faster or slower color change with H2 by varying the relative amounts of resazurin and Au-Pd NPs in solution. The results from this study are significant for future optical H2 sensor design.
Discovery of Novel Tacrine-Pyrimidone Hybrids as Potent Dual AChE/GSK-3 Inhibitors for the Treatment of Alzheimer's Disease
Yao, Hong,Uras, Giuseppe,Zhang, Pengfei,Xu, Shengtao,Yin, Ying,Liu, Jie,Qin, Shuai,Li, Xinuo,Allen, Stephanie,Bai, Renren,Gong, Qi,Zhang, Haiyan,Zhu, Zheying,Xu, Jinyi
, p. 7483 - 7506 (2021)
Based on a multitarget strategy, a series of novel tacrine-pyrimidone hybrids were identified for the potential treatment of Alzheimer's disease (AD). Biological evaluation results demonstrated that these hybrids exhibited significant inhibitory activities toward acetylcholinesterase (AChE) and glycogen synthase kinase 3 (GSK-3). The optimal compound 27g possessed excellent dual AChE/GSK-3 inhibition both in terms of potency and equilibrium (AChE: IC50 = 51.1 nM; GSK-3β: IC50 = 89.3 nM) and displayed significant amelioration on cognitive deficits in scopolamine-induced amnesia mice and efficient reduction against phosphorylation of tau protein on Ser-199 and Ser-396 sites in glyceraldehyde (GA)-stimulated differentiated SH-SY5Y cells. Furthermore, compound 27g exhibited eligible pharmacokinetic properties, good kinase selectivity, and moderate neuroprotection against GA-induced reduction in cell viability and neurite damage in SH-SY5Y-derived neurons. The multifunctional profiles of compound 27g suggest that it deserves further investigation as a promising lead for the prospective treatment of AD.
Photocatalytic degradation of dyes in water: Case study of indigo and of indigo carmine
Vautier, Manon,Guillard, Chantal,Herrmann, Jean-Marie
, p. 46 - 59 (2001)
The TiO2/UV photocatalytic degradations of indigo and of indigo carmine have been investigated both in aqueous heterogeneous suspensions and in the solid state. In addition to prompt removal of the color, TiO2/UV-based photocatalysis
Conjugation of tacrine with genipin derivative not only enhances effects on AChE but also leads to autophagy against Alzheimer's disease
Lin, Rongtian,Rao, Shuwen,Li, Yanbing,Zhang, Lei,Xu, Liyu,He, Yepu,Liu, Zhijun,Chen, Heru
, (2021)
Seven tacrine/CHR21 conjugates have been designed and synthesized. Compound 8-7 was confirmed as the most active AChE inhibitor with IC50 value of 5.8 ± 1.4 nM, which was 7.72-fold stronger than tacrine. It was also shown as a strong BuChE inhibitor (IC50 value of 3.7 ± 1.3 nM). 8-7 was clearly highlighted not only as an excellent ChEs inhibitor, but also as a good modulator on protein expression of AChE, p53, Bax, Bcl-2, LC3, p62, and ULK, indicating its functions against programmed cell apoptosis and decrease of autophagy. 8-7 significantly reversed the glutamate-induced dysfunctions including excessive calcium influx and release from internal organelles, overproduction of nitric oxide (NO) and Aβ high molecular weight oligomer. This compound can penetrate blood?brain barrier (BBB). The in vivo hepatotoxicity assay indicated that 8-7 was much less toxic than tacrine. Altogether, these data strongly support that 8-7 is a potential multitarget-directed ligand (MTDL) for treating Alzheimer's disease (AD).
Synthesis and characterization of schiff base complexes of o-vanillin and anthranilic acid and their biological evaluation
Pradhan, Rajeev,Kumar Sinha, Sumit,Verma, Punam,Kumar, Sunny,Sharma, Shivadhar
, p. 1989 - 1993 (2018)
Complexes of Schiff base derived from o-vanillin (2-hydroxy-3-methoxybenzaldehyde) and anthranilic acid (2-aminobenzoic acid) has been used for complexation with Mn(II), Fe(II) and Co(II). The complexes have been formulated as [ML2X2] where X = pyridine or α-picoline on the basic of their microanalysis. Infrared spectral study has been made to confirm the coordination sites of the Schiff base. The magnetic susceptibility and electronic spectral study leads to tetragonally distorted octahedral symmetry (T4h) of complexes. Their biological evaluation with different strains of bacteria suggest that the complexes are more active than the ligand against both Gram-positive and Gram-negative bacteria.
Chemoselective reduction of nitrobenzenes to aminobenzenes having reducible groups by a titanium(iv) oxide photocatalyst under gas- and metal-free conditions
Imamura, Kazuya,Hashimoto, Keiji,Kominami, Hiroshi
, p. 4356 - 4358 (2012)
m-Nitrovinylbenzene was chemoselectively reduced to m-aminovinylbenzene in a suspension of a TiO2 photocatalyst in the presence of a hole scavenger at room temperature under atmospheric pressure without the use of a precious metal or reducing gas, and nitrobenzenes having other reducible groups were also chemoselectively reduced to corresponding aminobenzenes. The Royal Society of Chemistry 2012.
The phosphate of pyridoxal-5′-phosphate is an acid/base catalyst in the mechanism of Pseudomonas fluorescens kynureninase
Phillips, Robert S.,Scott, Israel,Paulose, Riya,Patel, Akshay,Barron, Taylor Colt
, p. 1100 - 1109 (2014)
Kynureninase (l-kynurenine hydrolase, EC 3.7.1.3) catalyzes the hydrolytic cleavage of l-kynurenine to l-alanine and anthranilic acid. The proposed mechanism of the retro-Claisen reaction requires extensive acid/base catalysis. Previous crystal structures showed that Tyr226 in the Pseudomonas fluorescens enzyme (Tyr275 in the human enzyme) hydrogen bonds to the phosphate of the pyridoxal-5′-phosphate (PLP) cofactor. This Tyr residue is strictly conserved in all sequences of kynureninase. The human enzyme complexed with a competitive inhibitor, 3-hydroxyhippuric acid, showed that the ligand carbonyl O is located 3.7 A from the phenol of Tyr275 (Lima, S., Kumar, S., Gawandi, V., Momany, C. & Phillips, R. S. (2009) J. Med. Chem. 52, 389-396). We prepared a Y226F mutant of P. fluorescens kynureninase to probe the role of this residue in catalysis. The Y226F mutant has approximately 3000-fold lower activity than wild-type, and does not show the pKa values of 6.8 on kcat and 6.5 and 8.8 on kcat/Km seen for the wild-type enzyme (Koushik, S. V., Moore, J. A. III, Sundararaju, B. & Phillips, R. S. (1998) Biochemistry 37, 1376-1382). Wild-type kynureninase shows a resonance at 4.5 ppm in 31P-NMR, which is shifted to 5.0, 3.3 and 2.0 ppm when the potent inhibitor 5-bromodihydrokynurenine is added. However, Y226F kynureninase shows resonances at 3.6 and 2.5 ppm, and no change in the peak position is seen when 5-bromodihydrokynurenine is added. Taken together, these results suggest that Tyr226 mediates proton transfer between the substrate and the phosphate, which accelerates formation of external aldimine and gem-diol intermediates. Thus, the phosphate of PLP acts as an acid/base catalyst in the mechanism of kynureninase.
Specific influence of salts on the hydrolysis reaction rate of p-nitrophenyl anthranilate in binary acetonitrile-water solvents
Bayissa, Leta Danno,Ohmae, Yoshihito,Hojo, Masashi
, p. 294 - 300 (2014)
The hydrolysis reaction rates of p-nitrophenyl anthranilate (p-NPA) have been surveyed in aqueous buffer solutions mixed with acetonitrile (MeCN) containing various salts at 50 ± 0.1 °C. Increase in pH of the buffer solution from 8.50 to 10.0 results in an increase of the hydrolysis rate constant [log (k/s- 1)] in all solutions mixed with 0-75% (v/v) MeCN. The log (k/s- 1) values significantly decelerate as MeCN contents increase to about 50% (v/v). With further increment of MeCN contents, however, the reversal increases in log (k/s- 1) are observed. All the added salts significantly influence the hydrolysis rate in solutions containing the borate buffer of pH = 9.18. Alkali metal perchlorates (LiClO4and NaClO4) cause the deceleration with increasing salt concentration. The presence of as low as 0.1 mol dm- 3of NaN3causes a three-fold acceleration, compared to the rate without the salt in no MeCN media. The rate acceleration by NaN3becomes gradually weaker as the MeCN contents increase. Contrastingly, the rate acceleration by Et4NBr is enhanced with increasing MeCN contents. In 50% (v/v) MeCN solution, the acceleration in log (k/s- 1) caused by added salts is in the order of NaN3> (n-Bu)4NBr ~ Et4NBr > Et4NCl. The Arrhenius plots in the 50% (v/v) MeCN media without salts and with 0.20 mol dm- 3of LiClO4, NaN3and Et4NBr salts give the good linearity of high activation energy values in the temperature range of 35 to 60 ± 0.1°C, suggesting that the hydrolysis reactions are just of temperature dependence. The whole results have been discussed in terms of changes in the water structure and/or activities of H2O and OH-in the presence of both the added organic solvent and salts, and also in terms of the nucleophilicity of anions from the added salts in the modified media.
Crystal Structure of Escherichia coli Enterobactin-specific Isochorismate Synthase (EntC) Bound to its Reaction Product Isochorismate: Implications for the Enzyme Mechanism and Differential Activity of Chorismate-utilizing Enzymes
Sridharan, Sudharsan,Howard, Nigel,Kerbarh, Olivier,Blaszczyk, Michal,Abell, Chris,Blundell, Tom L.
, p. 290 - 300 (2010)
EntC, one of two isochorismate synthases in Escherichia coli, is specific to the biosynthesis of the siderophore enterobactin. Here, we report the crystal structure of EntC in complex with isochorismate and Mg2+at 2.3 A resolution, the first structure of a chorismate-utilizing enzyme with a non-aromatic reaction product. EntC exhibits a complex α+β fold like the other chorismate-utilizing enzymes, such as salicylate synthase and anthranilate synthase. Comparison of active site structures allowed the identification of several residues, not discussed previously, that might be important for the isochorismate activity of the EntC. Although EntC, MenF and Irp9 all convert chorismate to isochorismate, only Irp9 subsequently exhibits isochorismate pyruvate lyase activity resulting in the formation of salicylate and pyruvate as the reaction products. With a view to understanding the roles of these amino acid residues in the conversion of chorismate to isochorismate and to obtaining clues about the pyruvate lyase activity of Irp9, several mutants of EntC were generated in which the selected residues in EntC were substituted for those of Irp9: these included A303T, L304A, F327Y, I346L and F359Q mutations. Biochemical analysis of these mutants indicated that the side chain of A303 in EntC may be crucial in the orientation of the carbonyl to allow formation of a hydrogen bond with isochorismate. Some mutations, such as L304A and F359Q, give rise to a loss of catalytic activity, whereas others, such as F327Y and I346L, show that subtle changes in the otherwise closely similar active sites influence activity. We did not find a combination of these residues that conferred pyruvate lyase activity.
Chemoselective hydrogenation of functionalized nitroarenes using MOF-derived co-based catalysts
Wang, Xi,Li, Yingwei
, p. 56 - 65 (2016)
The synthesis, characterization, and application of nitrogen-doped carbon supported Co catalysts in selective hydrogenation of nitroarenes are described. The cobalt-based catalysts are prepared by simple pyrolysis of ZIF-67, a typical MOF material, under inert atmosphere. Physicochemical properties of the Co/C-N catalysts have been investigated by X-ray diffraction, elemental analysis, atomic absorption spectroscopy, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The Co-based materials were found to be highly efficient in the chemoselective hydrogenation of nitroarenes. A broad range of substituted nitroarenes are converted to the corresponding anilines in excellent yields under industrially viable conditions with other reducing groups remaining intact. In situ ATR-IR and XPS characterizations reveal that the Co-N centers present in the catalyst favor the preferential adsorption of nitro groups, leading to this unique chemoselectivity. The kinetic parameters of 4-nitrostyrene hydrogenation over the Co/C-N catalyst were investigated.
Facile fabrication of γ-Fe2O3-nanoparticle modified N-doped porous carbon materials for the efficient hydrogenation of nitroaromatic compounds
Cui, Xueliang,Zhang, Qiaolan,Tian, Meng,Dong, Zhengping
, p. 10165 - 10173 (2017)
Novel γ-Fe2O3-nanoparticle (NP) modified N-doped porous carbon materials (γ-Fe2O3/mCN) were prepared by one-pot pyrolysis of a mixture of melamine, polyacrylonitrile, and FeCl3·6H2O at different temperatures. At a pyrolysis temperature of 900 °C, γ-Fe2O3/mCN-900-20 exhibited a high surface area and a N content of 8.47%, caused by the complete pyrolysis of melamine and polyacrylonitrile at 900 °C. The obtained material γ-Fe2O3/mCN-900-20 was used as a cost-effective catalyst for the hydrogenation of nitrobenzene using N2H4·H2O as the reductant under mild reaction conditions. As compared to other catalysts (e.g., noble metal catalysts), γ-Fe2O3/mCN-900-20 exhibited high catalytic performance (TOF of 311.83 h-1, selectivity of 100%). During the catalytic hydrogenation of nitroaromatic compounds with reducible groups, e.g., alcoholic hydroxyl, halogen, and amino groups, an excellent selectivity close to 100% was achieved. Moreover, because the active sites of γ-Fe2O3 has magnetic performance, the catalyst can be easily recovered using a magnet, and reused at least four runs without an obvious activity decrease. Hence, the easily prepared, cost-effective and reusable γ-Fe2O3/mCN catalyst fabricated in this study demonstrates potential for applications in selective reduction of aromatic nitro compounds.
The roles of Ser-36, Asp-132 and Asp-201 in the reaction of Pseudomonas fluorescens Kynureninase
Phillips, Robert S.,Crocker, Mori,Lin, Richard,Idowu, O. Elijah,McCannon, David K.,Lima, Santiago
, p. 722 - 731 (2019)
Kynureninase from Pseudomonas fluorescens (Pfkynase)catalyzes the pyridoxal-5′-phosphate (PLP)dependent hydrolytic cleavage of L-kynurenine to give anthranilate and L-alanine. Asp-132 and Asp-201 are located in the structure near the pyridine NH of the PLP, with Asp-201 forming a hydrogen bond. Mutation of Asp-132 to alanine and glutamate and Asp-201 to glutamate results in reduced catalytic activity with L-kynurenine and β-benzoyl-L-alanine, but not O-benzoyl-L-serine. D132A, D132E D201E and S36A mutant Pfkynases all can form quinonoid and vinylogous amide intermediates with β-benzoyl-L-alanine, similar to wild-type enzyme. D132A, D132E, and D201E Pfkynase react more slowly with β-benzoyl-L-alanine and benzaldehyde to form an aldol product absorbing at 490 nm than wild-type, with D132E reacting the slowest. The 1H NMR spectra of wild-type and D201E Pfkynase are very similar in the low field region from 10 to 18 ppm, but that of D132A Pfkynase is missing a resonance at 13.1 ppm. These results show that these residues modulate the reactivity of the PLP at different stages during the reaction cycle. Ser-36 is located near the expected location of the carbonyl oxygen of the substrate. Mutation of Ser-36 to alanine results in a 230-fold reduction of kcat and 30-fold reduction in kcat/Km with L-kynurenine, but very little effect on the reaction of O-benzoyl-L-serine. Thus, the rate-determining step in the reaction of S36A Pfkynase is the Cβ-Cγ bond cleavage. These results support the hypothesis that Ser-36 together with Tyr-226 is part of an oxyanion hole that polarizes the carbonyl of the substrate in the catalytic mechanism of Pfkynase.
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Dunn,Prysiazniuk
, p. 285,288 (1961)
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Strong in vitro and in vivo cytotoxic effects of two platinum(II) complexes with cryptolepine derivatives
Qin, Li-Qin,Wei, Zu-Zhuang,Yang, Lin,Qin, Qi-Pin,Zeng, Jia-Jing,Tan, Ming-Xiong,Liang, Hong
, p. 1419 - 1426 (2021)
Two mononuclear Pt(II) compounds, [Pt(BQL1)Cl]Cl (BQL1-Pt) and [Pt(BQL2)Cl]Cl (BQL2-Pt), with [5-(benzo[4,5]furo[3,2-b]quinolin-11-yloxy)-pentyl]-bis-pyridin-2-ylmethyl-amine (BQL1) and [9-(benzo[4,5]furo[3,2-b]quinolin-11-yloxy)-nonyl]-bis-pyridin-2-ylmethyl-amine (BQL2), were prepared as new chemotypes for potential antitumor agents. In this study, the effects of cryptolepine derivatives in BQL1-Pt, 2,2′-dipicolylamine Pt(II) complex, and BQL2-Pt on cellular Pt(II) accumulation, cytotoxicity, and in vitro and in vivo antitumor activities against T-24 cancer cells and normal HL-7702 cells were evaluated. BQL1-Pt and BQL2-Pt displayed cytotoxic activities in the micromolar range (1.3 ± 0.1 and 0.2 ± 0.2 μM, respectively) on T-24 cancer cells; however, they did not exhibit any toxicity against HL-7702 cells. They triggered T-24 cell apoptosis through a mitochondrial dysfunction pathway. BQL1-Pt and BQL2-Pt prepared from the neutral BQL1 and BQL2 ligands with cryptolepine derivatives showed better antitumor activities than 2,2′-dipicolylamine. Furthermore, BQL2-Pt effectively inhibited the growth of bladder T-24 tumor in vivo. BQL2-Pt could be a potential therapeutic candidate for cancers. [Figure not available: see fulltext.]
Cu-catalyzed reduction of azaarenes and nitroaromatics with diboronic acid as reductant
Pi, Danwei,Zhou, Haifeng,Zhou, Yanmei,Liu, Qixing,He, Renke,Shen, Guanshuo,Uozumi, Yasuhiro
, p. 2121 - 2129 (2018)
A ligand-free copper-catalyzed reduction of azaarenes with diboronic acid as reductant in an aprotic solvent under mild conditions has been developed. Most interestingly, the nitroazaarenes could be reduced exclusively to give the corresponding amines without touching the azaarene moieties. Furthermore, the reductive amination of aromatic nitro compounds and aromatic aldehydes has also been realized. A series of hydrogenated azaarenes and secondary amines were obtained with good functional group tolerance.
Efficient reduction of nitroarenes to the corresponding anilines with sulfur in basic media under solvent-free conditions
Niknam, Khodabakhsh,Kiasat, Ali Reza,Kazemi, Foad,Hossieni, Abolghasem
, p. 1385 - 1389 (2003)
Aromatic nitro compounds can be conveniently reduced to the corresponding primary amines in the presence of S8 under solvent-free conditions in excellent yields. Alumina supported NaOH catalyses this transformation. Chemoselectivity was observed in the reduction of the nitro group in the presence of phenol, carboxylic acid, aldehyde, and benzyl halide groups.
Pd(0) supported on N-doped graphene quantum dot modified cellulose as an efficient catalyst for the green reduction of nitroaromatics
Keshipour, Sajjad,Adak, Kamran
, p. 89407 - 89412 (2016)
A new efficient catalyst was introduced for the green reduction of nitroaromatics. The catalyst was obtained via modification of cellulose with N-doped graphene quantum dots and Pd nanoparticles. The new cellulose nanocomposite after characterization was applied as the catalyst in the reduction reaction of nitroaromatics using NaBH4 at room temperature. Aromatic amines were obtained as the product of the reduction reaction over 2 h. This reaction has green reaction conditions such as mild reaction conditions, high yield, green solvent and recyclable catalyst. Also, the recovered catalyst is applicable in the reduction reaction 6 times without significant decrease in activity.
Copper mediated C-H amination with oximes: En route to primary anilines
Xu, Lin-Lin,Wang, Xing,Ma, Biao,Yin, Ming-Xing,Lin, Hai-Xia,Dai, Hui-Xiong,Yu, Jin-Quan
, p. 5160 - 5164 (2018)
Here we report an efficient Cu(i)-mediated C-H amination reaction with oximes as amino donors to introduce NH2 groups directly. Various strongly coordinating heterocycles including quinoline, pyrimidine, pyrazine, pyrazole and triazole were tolerated well. The potential utility was further demonstrated in a late-stage modification of telmisartan (an antagonist for the angiotensin II receptor).
Aglycone Ebselen and β- D -Xyloside Primed Glycosaminoglycans Co-contribute to Ebselen β- D -Xyloside-Induced Cytotoxicity
Tang, Yang,Zhang, Siqi,Chang, Yajing,Fan, Dacheng,Agostini, Ariane De,Zhang, Lijuan,Jiang, Tao
, p. 2937 - 2948 (2018)
Most β-d-xylosides with hydrophobic aglycones are nontoxic primers for glycosaminoglycan assembly in animal cells. However, when Ebselen was conjugated to d-xylose, d-glucose, d-galactose, and d-lactose (8A-D), only Ebselen β-d-xyloside (8A) showed significant cytotoxicity in human cancer cells. The following facts indicated that the aglycone Ebselen and β-d-xyloside primed glycosaminoglycans co-contributed to the observed cytotoxicity: 1. Ebselen induced S phase cell cycle arrest, whereas 8A induced G2/M cell cycle arrest; 2. 8A augmented early and late phase cancer cell apoptosis significantly compared to that of Ebselen and 8B-D; 3. Both 8A and phenyl-β-d-xyloside primed glycosaminoglycans with similar disaccharide compositions in CHO-pgsA745 cells; 4. Glycosaminoglycans could be detected inside of cells only when treated with 8A, indicating Ebselen contributed to the unique property of intracellular localization of the primed glycosaminoglycans. Thus, 8A represents a lead compound for the development of novel antitumor strategy by targeting glycosaminoglycans.
MOF-derived Ni-based nanocomposites as robust catalysts for chemoselective hydrogenation of functionalized nitro compounds
Tang, Bo,Song, Wei-Chao,Yang, En-Cui,Zhao, Xiao-Jun
, p. 1531 - 1539 (2017)
Porous graphitic carbon layers encapsulating Ni nanoparticles (Ni@C) were prepared by a facile thermolysis of a Ni-containing metal-organic framework, the structure of which were characterized by power X-ray diffraction (XRD), N2 adsorption-desorption, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) in detail. The resulting Ni@C nanocomposites served as highly efficient and magnetically recyclable catalysts for the hydrogenation of diverse functionalized nitro compounds to the corresponding anilines under relatively milder conditions. The high catalytic performance and the enhanced stability are ascribed to the synergistic effects and electron transfer between the metallic Ni and graphitic carbon as well as the unique encapsulation structure. The achieved success in the MOF-derived Ni@C nanocomposites may pave the way for designing environmentally benign catalytic hydrogenation processes for industrial applications.
Gold nanoparticles anchored onto the magnetic poly(ionic-liquid) polymer as robust and recoverable catalyst for reduction of Nitroarenes
Moghaddam, Firouz Matloubi,Ayati, Seyed Ebrahim,Firouzi, Hamid Reza,Hosseini, Seyed Hassan,Pourjavadi, Ali
, (2017)
Gold nanoparticles supported on poly ionic-liquid magnetic nanoparticles (MNP@PIL@Au) were synthesized by reduction of HAuCl4 with sodium borohydride. The synthesized catalyst was characterized using by AAS, TEM, FT-IR, EDS, TGA and XRD techniques. The performance of the synthesized catalyst was investigated in the reduction of nitroarenes with NaBH4. The reaction was carried out for various nitroarenes in water and mild conditions with high yields. The catalyst selectivity for the reduction of nitro group in the presences of other functional groups such as halides and alkynes was fairly well. The recycling of the catalyst was done 8 times without any significant loss of its catalytic activity.
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Isbell,Henze
, p. 2096 (1944)
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Synthesis of oxazolidinones from N-aryl-carbamate and epichlorohydrin under mild conditions
Buscemi, Silvestre,Insuasty, Braulio,Marzullo, Paola,Moreno, Leydi Marcela,Piccionello, Antonio Palumbo
supporting information, p. 140 - 155 (2022/03/27)
The reaction conditions for an enantiospecific synthesis of various N-aryl-oxazolidinones from N-aryl-carbamates and (R) or (S) epichlorohydrin were optimized. The N-aryl-oxazolidinones were applied to the synthesis of compounds of biological interest such as DuP 721, toloxatone and a linezolid analogue.
NaI/PPh3-Mediated Photochemical Reduction and Amination of Nitroarenes
Qu, Zhonghua,Chen, Xing,Zhong, Shuai,Deng, Guo-Jun,Huang, Huawen
supporting information, p. 5349 - 5353 (2021/07/21)
A mild transition-metal- and photosensitizer-free photoredox system based on the combination of NaI and PPh3 was found to enable highly selective reduction of nitroarenes. This protocol tolerates a broad range of reducible functional groups such as halogen (Cl, Br, and even I), aldehyde, ketone, carboxyl, and cyano. Moreover, the photoredox catalysis with NaI and stoichiometric PPh3 provides also an alternative entry to Cadogan-type reductive amination when o-nitrobiarenes were used.
Copper nanoparticles (CuNPs) catalyzed chemoselective reduction of nitroarenes in aqueous medium
Chand, Dillip Kumar,Rai, Randhir
, (2021/08/20)
Abstract: A procedure for practical synthesis of CuNPs from CuSO4·5H2O is established, under appropriate reaction conditions, using rice (Oryza sativa) as an economic source of reducing as well as a stabilizing agent. Optical and microscopic techniques are employed for the characterization of the synthesized CuNPs and the sizes of the particles were found to be in the range of 8 ± 2 nm. The nanoparticles are used as a catalyst for chemoselective reduction of aromatic nitro compounds to corresponding amines under ambient conditions and water as a reaction medium. Graphic abstract: CuNPs are synthesized using hydrolysed rice and used as catalyst for chemoselective reduction of nitroarenes to their corresponding amines in water. [Figure not available: see fulltext.]
