- 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; 0092; 0095; 0102
(2021/07/24)
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- Homarine Alkyl Ester Derivatives as Promising Acetylcholinesterase Inhibitors
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Reversible acetylcholinesterase (AChE) inhibitors are key therapeutic tools to modulate the cholinergic connectivity compromised in several degenerative pathologies. In this work, four alkyl esters of homarine were synthesized and screened by using Electrophorus electricus AChE and rat brain AChE-rich fraction. Results showed that all homarine alkyl esters are able to inhibit AChE by a competitive inhibition mode. The effectiveness of AChE inhibition increases with the alkyl side chain length of the homarine esters, being HO?C16 (IC50=7.57±3.32 μM and Ki=18.96±2.28 μM) the most potent inhibitor. The fluorescence quenching studies confirmed that HO?C16 is the compound with higher selectivity and affinity for the tryptophan residues in the catalytic active site of AChE. Preliminary cell viability studies showed that homarine esters display no toxicity for human neuronal SH-SY5Y cells. Thus, the long-chain homarine esters emerge as new anti-cholinesterase agents, with potential to be considered for therapeutic applications development.
- Jo?o, Karen G.,Videira, Romeu A.,Paiva-Martins, Fátima,Valent?o, Patrícia,Pereira, David M.,Andrade, Paula B.
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p. 3315 - 3325
(2021/08/30)
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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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- 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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supporting information
(2020/09/16)
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- Lanthanoid pyridyl-β-diketonate 'triangles'. New examples of single molecule toroics
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Trinuclear lanthanoid clusters have been synthesised and investigated as toroidal spin systems. A pyridyl functionalised β-diketonate, 1,3-bis(pyridin-2-yl)propane-1,3-dione (o-dppdH) has been used to synthesise a family of clusters of the form [Dy3(OH)2(o-dppd)3Cl2(H2O)4]Cl2·7H2O (1), [Tb3(o-dppd)3(μ3-OH)2(CH3CH2OH)3Cl3][Tb3(o-dppd)3(μ3-OH)2(H2O)(CH3CH2OH)2Cl3]Cl2·H2O (2), [Ho3(OH)2(o-dppd)3Cl(H2O)5]Cl3·3H2O (3) and [Er3(OH)2(o-dppd)3Cl2(H2O)3(CH3OH)]Cl2·3H2O·CH3OH (4). Despite the previous occurrence of this structural motif in the literature, these systems have not been widely investigated in terms of torodic behaviour. Magnetic studies were used to further characterise the complexes. DC susceptibility studies support weak antiferromagnetic exchange in the complexes. Slow magnetic relaxation behaviour is observed in the dynamic AC magnetic studies for complex 1. Theoretical studies predict that complex 1 and 3 have a non-magnetic ground state based on a toroidal arrangement of spins. Changes to the coordination environment in 2 do not support a toroic spin state. The prolate nature of the ErIII centres in complex 4 and large transverse anisotropy do not support the toroidal arrangement of lanthanoid spins in the complex.
- Caporale, Chiara,Fuller, Rebecca O.,Massi, Massimiliano,Murray, Keith S.,Ogden, Mark I.,Phonsri, Wasinee,Rajaraman, Gopalan,Sobolev, Alexandre N.,Swain, Abinash
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supporting information
p. 17421 - 17432
(2020/12/28)
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- Construction of Esters through Sulfuryl Fluoride (SO 2 F 2) Mediated Dehydrative Coupling of Carboxylic Acids with Alcohols at Room Temperature
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A facile method for the construction of esters through dehydrative coupling of carboxylic acids with alcohols is developed. The reactions are mediated by sulfuryl fluoride (SO 2 F 2) at room temperature and proceed with high efficiency. The method has several advantages including broad substrate scope, mild conditions, excellent functional group compatibility and affords high yields, even on gram scale.
- Qin, Hua-Li,S Alharbi, Njud,Wang, Shi-Meng
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p. 3901 - 3907
(2019/10/11)
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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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Paragraph 0061-0063
(2019/03/24)
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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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supporting information
p. 5801 - 5806
(2019/08/02)
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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 0484
(2019/10/29)
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- Directed C-H Functionalization Reactions with a Picolinamide Directing Group: Ni-Catalyzed Cleavage and Byproduct Recycling
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An efficient strategy for the cleavage of the picolinamide directing group (DG) and recycling of the byproduct generated has been developed. In this protocol, picolinamides were first Boc activated into tertiary N-Boc-N-substituted picolinamides. These were then cleaved via a Ni-catalyzed esterification reaction with EtOH to give valuable N-Boc protected amines. Ni(cod)2 was used as a catalyst without any ligands or base additives. The byproduct, ethyl 2-picolinate can be used to install the picolinamide DG in a direct or indirect manner on amines. The protocol exhibits a broad functional group tolerance and high yields. To demonstrate the utility of this approach, it was applied on many selected examples from the recent C-H functionalization literature featuring 2-picolinamide as a DG.
- Biswas, Sovan,Bheemireddy, Narendraprasad Reddy,Bal, Mathias,Van Steijvoort, Ben F.,Maes, Bert U. W.
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p. 13112 - 13123
(2019/10/17)
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- Porous organic cage stabilised palladium nanoparticles: Efficient heterogeneous catalysts for carbonylation reaction of aryl halides
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Porous organic cage stabilised palladium nanoparticles were successfully prepared using methanol as a mild reductant. The as-prepared porous composite materials show high catalytic activity for the carbonylation reaction of aryl halides under mild conditions.
- Zhang, Yong,Xiong, Yu,Ge, Jin,Lin, Rui,Chen, Chen,Peng, Qing,Wang, Dingsheng,Li, Yadong
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supporting information
p. 2796 - 2799
(2018/03/21)
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- Selective Extraction of Americium(III) over Europium(III) Ions with Pyridylpyrazole Ligands: Structure–Property Relationships
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To clarify the structure–property relationships of pyridylpyrazole ligands and provide guidance for the design of new and more efficient ligands for the selective extraction of actinides over lanthanides, a series of alkyl-substituted pyridylpyrazole ligands with different branched chains at different positions of the pyrazole ring were synthesized. Extraction experiments showed that the pyridylpyrazole ligands exhibited good selective extraction abilities for AmIIIions, and the steric effects of the branched chain had a significant impact on the distribution ratios of AmIIIand EuIIIions as well as the separation factor. Moreover, both slope analyses and UV/Vis spectrometry titrations indicated the formation of a 1:1 complex of 2-(1-octyl-1H-pyrazol-3-yl)pyridine (C8-PypzH) with EuIIIions. The stability constant (log K) for this complex obtained from the UV/Vis titration was 4.45 ± 0.04. Single crystals of the complexes of 3-(2-pyridyl)pyrazole (PypzH) with Eu(NO3)3and Sm(NO3)3were obtained; PypzH acts as a bidentate ligand in the crystal structures, and the N atom with a bound H atom did not participate in the coordination. In general, this study revealed some interesting findings on the effects of the alkyl-chain structure and the special complexation between pyridylpyrazole ligands and LnIIIions.
- Su, Dongping,Liu, Ying,Li, Shimeng,Ding, Songdong,Jin, Yongdong,Wang, Zhipeng,Hu, Xiaoyang,Zhang, Lirong
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p. 651 - 658
(2017/02/05)
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- MULTISUBSTITUTED AROMATIC COMPOUNDS AS INHIBITORS OF THROMBIN
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There are provided inter alia multisubstituted aromatic compounds useful for the inhibition of thrombin, which compounds include substituted pyrazolyl or substituted triazolyl. There are additionally provided pharmaceutical compositions. There are additionally provided methods of treating and preventing a disease or disorder, which disease or disorder is amenable to treatment or prevention by the inhibition of thrombin.
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Paragraph 0403-0405
(2017/12/07)
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- Noncovalent Interactions in Ir-Catalyzed C-H Activation: L-Shaped Ligand for Para-Selective Borylation of Aromatic Esters
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An efficient strategy for the para-selective borylation of aromatic esters is described. For achieving high para-selectivity, a new catalytic system has been developed modifying the core structure of the bipyridine. It has been proposed that the L-shaped ligand is essential to recognize the functionality of the oxygen atom of the ester carbonyl group via noncovalent interaction, which provides an unprecedented controlling factor for para-selective C-H activation/borylation.
- Hoque, Md Emdadul,Bisht, Ranjana,Haldar, Chabush,Chattopadhyay, Buddhadeb
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supporting information
p. 7745 - 7748
(2017/06/21)
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- Graphene Oxide: An Efficient Acid Catalyst for the Construction of Esters from Acids and Alcohols
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Graphene oxide was found to be an efficient and reusable acid catalyst for the esterification reaction. A wide range of aliphatic and aromatic acids and alcohols were compatible with the standard conditions and afforded the corresponding products in good yields. The heterogeneous catalyst can be easily recovered and recycled in dichloro-ethane solvent with good catalytic activity.
- Chen, Zhengwang,Wen, Yuelu,Fu, Yejuan,Chen, Hai,Ye, Min,Luo, Guotian
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supporting information
p. 981 - 985
(2017/05/05)
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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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- 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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Paragraph 0037
(2017/09/01)
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- Cobalt-Catalyzed Esterification of Amides
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The first cobalt-catalyzed amide activation of N-Boc-amides, and their conversion into esters, is reported here. This new methodology presents a very practical process that does not require an inert atmosphere, uses an inexpensive cobalt catalyst, and proceeds under mild reaction conditions. This catalytic system has a broad substrate scope and has been shown to be highly efficient, with catalyst loadings as low as 1 mol %.
- Bourne-Branchu, Yann,Gosmini, Corinne,Danoun, Grégory
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supporting information
p. 10043 - 10047
(2017/08/01)
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- Room Temperature Carbonylation of (Hetero) Aryl Pentafluorobenzenesulfonates and Triflates using Palladium-Cobalt Bimetallic Catalyst: Dual Role of Cobalt Carbonyl
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An efficient method for the carbonylation of (hetero) aryl pentafluorobenzenesulfonates and triflates under exceptionally mild conditions using palladium/dicobalt octacarbonyl [Pd/Co2(CO)8] has been developed. Besides acting as carbon monoxide (CO) source, Co2(CO)8enhances the reaction rate by accelerating the CO insertion through an in situ generated bimetallic palladium cobalt tetracarbonyl [Pd-Co(CO)4] complex. Under the optimized reaction condition, carbonylation of a wide range of activated and deactivated, as well as sterically hindered and heteroaromatic, substrates proceeded efficiently at room temperature. The high chemoselectivity and improved synthesis of biologically relevant Isoguvacine and Lazabemide intermediates highlights its scope as a valuable synthetic method. The generality of this protocol was further extended to other electrophiles (bromides, chlorides and tosylates). (Figure presented.).
- Joseph, Jayan T.,Sajith, Ayyiliath M.,Ningegowda, Revanna C.,Shashikanth, Sheena
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p. 419 - 425
(2017/02/10)
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- Development and Applications of Transesterification Reactions Catalyzed by N-Heterocyclic Olefins
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A novel method to utilize N-heterocyclic olefins (NHOs), the alkylidene derivatives of N-heterocycic carbenes, as organocatalysts to promote transesterification reactions has been developed. Because of their strong Br?nsted/Lewis basicity, NHOs can enhance the nucleophilicity of alcohols for their acylation reactions with carboxylic esters. This transformation can be employed in industrially relevant processes such as the production of biodiesel, the depolymerization of polyethylene terephthalate (PET) from plastic bottles for recycling purposes, and the ring-opening polymerization of cyclic esters to form biodegradable polymers such as polylactide (PLA) and polycaprolactone (PCL).
- Blümel, Marcus,Noy, Janina-Miriam,Enders, Dieter,Stenzel, Martina H.,Nguyen, Thanh V.
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supporting information
p. 2208 - 2211
(2016/06/01)
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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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- Potent antimicrobial agents against azole-resistant fungi based on pyridinohydrazide and hydrazomethylpyridine structural motifs
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Abstract Schiff base derivatives have recently been shown to possess antimicrobial activity, and these derivatives include a limited number of salicylaldehyde hydrazones. To further explore this structure-activity relationship between salicylaldehyde hydrazones and antifungal activity, we previously synthesized and analyzed a large series of salicylaldehyde and formylpyridinetrione hydrazones for their ability to inhibit fungal growth of both azole-susceptible and azole-resistant species of Candida. While many of these analogs showed excellent growth inhibition with low mammalian cell toxicity, their activity did not extend to azole-resistant species of Candida. To further dissect the structural features necessary to inhibit azole-resistant fungal species, we synthesized a new class of modified salicylaldehyde derivatives and subsequently identified a series of modified pyridine-based hydrazones that had potent fungicidal antifungal activity against multiple Candida spp. Here we would like to present our synthetic procedures as well as the results from fungal growth inhibition assays, mammalian cell toxicity assays, time-kill assays and synergy studies of these novel pyridine-based hydrazones on both azole-susceptible and azole-resistant fungal species.
- Backes, Gregory L.,Jursic, Branko S.,Neumann, Donna M.
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p. 3397 - 3407
(2015/08/03)
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- Gold nanoparticles supported on metal oxides as catalysts for the direct oxidative esterification of alcohols under mild conditions
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Gold nanoparticles supported on metal oxides were used to catalyze the direct oxidative esterification of alcohols; esters were obtained using molecular oxygen as an oxidant under ambient temperature and pressure. Higher activities for the reaction between the benzyl alcohol and methanol were obtained over Au/CeO2 and Au/ZrO2 than Au/TiO2 (anatase), Au/HT (hydrotalcite) and Au/Al2O3. These catalysts were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), atomic absorption spectroscopy (AAS) and X-ray photoelectron spectroscopy (XPS). The distribution of gold nanoparticles was uniform; no change of chemical states occurred for supports and gold nanoparticles after the catalysts were reused 10 times. The oxidative esterification of various alcohols over these catalysts could also occur under optimized reaction conditions. The substituted benzyl alcohols and cinnamyl alcohols were more active than heterocyclic alcohols and aliphatic alcohols because their α-H could be eliminated more easily during the induction of adsorbed dioxygen. Self-oxidative esterification was available for benzyl alcohol in inert solvents with low polarity indexes. A reaction mechanism was proposed for the synthesis of esters from alcohols with molecular oxygen.
- Wei, Huili,Li, Jingyi,Yu, Jing,Zheng, Jianwei,Su, Haiquan,Wang, Xiaojing
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- Metal-free aerobic oxidative esterification of aldehydes in the presence of cyanide
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A metal-free aerobic oxidative esterification of aldehydes in the presence of cyanide is described. Various aromatic aldehydes and sterically congested alcohols were amenable to this protocol. In addition, this method could be extended to the preparation of thioesters with a thiol in place of an alcohol. Furthermore, the cyanide-mediated aerobic oxidation of aldehydes was applied to the synthesis of lactones via intramolecular esterification in the absence of an alcohol.
- Kim, Yoo-Jin,Cheon, Cheol-Hong
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supporting information
p. 2055 - 2061
(2015/08/18)
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- MULTISUBSTITUTED AROMATIC COMPOUNDS AS SERINE PROTEASE INHIBITORS
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There are provided inter alia multisubstituted aromatic compounds useful for the inhibition of kallikrein, which compounds include substituted pyrazolyl or substituted triazolyl. There are additionally provided pharmaceutical compositions. There are additionally provided methods of treating and preventing certain diseases or disorders, which disease or disorder is amenable to treatment or prevention by the inhibition of kallikrein.
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Paragraph 0265; 0266
(2014/09/29)
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- A novel chemosensor with visible light excitability for sensing Zn 2+ in physiological medium and in HeLa cells
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In the present study a novel imine-hydrazone based fluorescent chemosensor (L1) for efficient and selective sensing of Zn2+ over other biologically important metal ions under physiological conditions is reported. An enhancement in fluorescence emission intensity of the developed probe with a red shift of ~25 nm was observed for Zn2+, whereas other metal ions failed to reveal any significant change in the emission spectra. Interestingly, the receptor functioned under completely physiological conditions (99.7% HEPES buffer) and has visible light excitability. Sensing of Zn2+ was investigated in detail by absorption spectroscopy, emission spectroscopy, DFT calculation, 1H-NMR titration experiment and ESI-MS experiment. The association constant between L1 and Zn2+ was found to be 5.58 × 105 M-1. The receptor could detect as low as 69 ppb Zn2+. Sensing of Zn2+ is proposed through switch-on of intramolecular charge transfer (ICT) and chelation enhanced fluorescence (CHEF) processes after the introduction of Zn2+ into the free ligand. The developed receptor was non-toxic and rendered intracellular sensing of Zn2+ in HeLa cells through fluorescence imaging studies. This journal is the Partner Organisations 2014.
- Datta, Barun Kumar,Thiyagarajan, Durairaj,Samanta, Soham,Ramesh, Aiyagari,Das, Gopal
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p. 4975 - 4982
(2014/07/07)
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- Pd-containing organopolyoxometalates derived from Dawson polyoxometalate [P2W15V3O62]9-: Lewis acidity and dual site catalysis
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Grafting of a palladium complex to the Dawson vanadotungstate polyanion [P2W15V3O62]9- via an organic ligand generates a large family of pincer-type hybrid polyoxometalates. The palladium-POM derivatives have dual catalytic properties. Unlike their parent inorganic polyanions, they catalyze allylations while retaining their oxidant character, which leads to single-pot dual site catalysis. This opens a new route for multicatalytic reactions.
- Riflade, Benoit,Lachkar, David,Oble, Julie,Li, Joaquim,Thorimbert, Serge,Hasenknopf, Bernold,Lacote, Emmanuel
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supporting information
p. 3860 - 3863
(2014/08/18)
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- Microwave-induced synthesis and anti-nemic activity of 4-amino-3-mercapto-5-pyridin-2-yl-4H-1,2,4-triazole Schiff bases
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A series of twenty Schiff bases, 4-(benzylideneamino)-3-mercapto-5-pyridin-2-yl-4H-1,2,4-triazoles 6a-t, designed incorporating the picolinic acid moiety present in fusaric acid, a natural nematicide isolated from Fusarium oxysporum EF119, have been synthesized in MW-induced conditions and characterized using 1H and 13C NMR, FT-IR spectroscopy and elemental analysis. The Schiff bases obtained in high yields and screened for anti-nemic activity against Meloidogyne incognita and Rotylenchulus reniformis. Some of the test compounds show promising nematicidal and nematode repelling activity. 4-(4-Methoxybenzylideneamino)-3-mercapto-5-pyridin-2-yl-4H-1,2,4-triazole 6m, exhibits the highest nematicidal activity (LC50=218 μg mL-1, M. incognita and 174 μg mL-1, R. reniformis).
- Mandal, Abhishek,Dutta,Gupta
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p. 228 - 239
(2015/03/04)
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- Alkali-metal ion catalysis in nucleophilic substitution reactions of 5-Nitro-8-quinolyl picolinate with alkali metal ethoxides: Effect of modification of nonleaving group from benzoyl to picolinyl on reactivity and transition state structure
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A kinetic study on nucleophilic substitution reaction of 5-nitro-8-quinolyl picolinate (6) with alkali-metal ethoxides (EtOM; M = K, Na, and Li) in anhydrous ethanol is reported. The plot of kobsd vs. [EtOM] curves upward in the absence of crown ethers but is linear with significantly decreased reactivity in the presence of crown ethers. Dissection of kobsd into kEtO- and kEtOM (i.e., the second-order rate constants for the reactions with the dissociated EtO- and ion-paired EtOM, respectively) has revealed that the ion-paired EtOM is significantly more reactive than the dissociated EtO- (e.g., kEtOM/k EtO- = 33.4-141). This indicates that the reaction of 6 is catalyzed by M+ ions in the order Na+ > Li+ > K+ and the catalytic effect disappears in the presence of a proper crown ether. Picolinate ester 6 is much more reactive and is more strongly catalyzed by M+ ions than 5-nitro- 8-quinolyl benzoate (5). It has been concluded that M+ ions catalyze the reaction of 6 by increasing electrophilicity of the reaction center through a cyclic transition state, which is structurally not possible for the reaction of 5.
- Jeon, Seong Hoon,Yoon, Jung Hwan,Kim, Min-Young,Um, Ik-Hwan
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p. 1506 - 1510
(2014/06/09)
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- Photolysis and thermolysis of pyridyl carbonyl azide monolayers on single-crystal platinum
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The photochemical and thermal reactivity of a number of acyl azide-substituted pyridine compounds, namely nicotinyl azide, isonicotinyl azide, picolinyl azide and dinicotinyl azide with investigated as saturated monolayers on a single-crystal Pt(111) surface in an ultrahigh vacuum chamber. Multilayers of the substrates exhibited a maximum rate of desorption at 270 K, above which, stable saturated monolayers formed as characterized by reflection-absorption infrared spectroscopy by observation of C=O and N 3 bands at 1700 cm-1, and 2100 and 1300 cm-1 respectively. The monolayers were stable up to 400 K. Photolysis of the monolayer (or heating above 400 K) results in the formation of the respective isocyanate intermediate after loss of nitrogen as evidenced by the appearance of a new infrared band at 2260 cm-1 with concomitant loss of the azide bands. The resulting isocyanate saturated monolayer is stable in absence of nucleophiles, but can be quenched with appropriate nucleophiles. Saturated monolayers of a number of acyl azide-substituted pyridine compounds, namely nicotinyl azide, isonicotinyl azide, picolinyl azide and dinicotinyl azide, were formed on single-crystal Pt(111) surfaces in a UHV chamber. These monolayers were characterized by RAIR and thermal programmed desorption. Photolysis or thermolysis of these saturated monolayers leads to the corresponding isocyanate via a Curtius rearrangement.
- Adkinson, Dana K.,Magri, David C.,Pitters, Jason L.,Griffiths, Keith,Norton, Peter R.,Workentin, Mark S.
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p. 1020 - 1028
(2013/09/24)
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- Novel 1,3,4-oxadiazole thioether derivatives targeting thymidylate synthase as dual anticancer/antimicrobial agents
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A series of novel 1,3,4-oxadiazole thioether derivatives (compounds 9-44) were designed and synthesized as potential inhibitors of thymidylate synthase (TS) and as anticancer agents. The in vitro anticancer activities of these compounds were evaluated against three cancer cell lines by the MTT method. Among all the designed compounds, compound 18 bearing a nitro substituent exhibited more potent in vitro anticancer activities with IC50 values of 0.7 ± 0.2, 30.0 ± 1.2, 18.3 ± 1.4 μM, respectively, which was superior to the positive control. In the further study, it was identified as the most potent inhibitor against two kinds of TS protein (for human TS and Escherichia coli TS, IC50 values: 0.62 and 0.47 μM, respectively) in the TS inhibition assay in vitro and the most potent antibacterial agents with MIC (minimum inhibitory concentrations) of 1.56-3.13 μg/mL against the tested four bacterial strains. Molecular docking and 3D-QSAR study supported that compound 18 can be selected as dual antitumor/antibacterial candidate in the future study.
- Du, Qian-Ru,Li, Dong-Dong,Pi, Ya-Zhou,Li, Jing-Ran,Sun, Jian,Fang, Fei,Zhong, Wei-Qing,Gong, Hai-Bin,Zhu, Hai-Liang
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p. 2286 - 2297
(2013/05/09)
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- The dual role of ionic liquid BmimBF4, precursor of N-heterocyclic carbene and solvent, in the oxidative esterification of aldehydes
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Room temperature ionic liquid BmimBF4 (1-butyl-3- methylimidazolium tetrafluoroborate) has been utilized in the N-heterocyclic carbene-catalyzed oxidation of aldehydes to yield esters. In the presence of MnO2 as oxidant and of DBU and caesium carbonate as bases, aromatic, heteroaromatic and aliphatic esters have been isolated in good to excellent yields. The recyclability of the used ionic liquid along with the excess of inorganic reagents has been proved. The simple and cheap BmimBF4 ionic liquid played the dual role of precatalyst and solvent. This is the first time that such a reaction has been carried out with an ionic liquid as solvent.
- Chiarotto, Isabella,Feroci, Marta,Sotgiu, Giovanni,Inesi, Achille
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p. 8088 - 8095
(2013/08/23)
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- P-Sulfonic acid calix[n]arenes as homogeneous and recyclable organocatalysts for esterification reactions
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Esterification yields were significantly improved using calix[n]arenes catalysts under simple conditions. p-Sulfonic acid calix[4]arene and p-sulfonic acid calix[6]arene were powerful organocatalysts in several esterification reactions, which showed activity comparable or even superior to other well-established acids catalysts, such as, sulfuric acid, p-toluenesulfonic acid, and p-hydroxybezenesulfonic acid described in the literature.
- Fernandes, Sergio Antonio,Natalino, Ricardo,Gazolla, Poliana Aparecida Rodrigues,Da Silva, Márcio José,Jham, Gulab Newandram
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experimental part
p. 1630 - 1633
(2012/04/17)
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- Syntheses, crystal structures, and spectral characterization of three new asymmetrical substituted triaryltriazoles
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Triaryltriazoles are of interest in iron(II) complexes designed to study spin-crossover properties. In this study, three new asymmetrical substituted triaryltriazoles, 3-(p-R-phenyl)-4-(p-chlorophenyl)-5-(2-pyridyl)-1,2,4- triazoles (R = OCH3, 5a; Cl, 5b; Br, 5c), were successfully synthesized from 2-picolinic acid by a three-step reaction through an intermediate N-(p-R-phenylcarbonyl)-N'-(2-pyridylcarbonyl)hydrazine (4a-4c). Yield of 5a-5c is in the range from 74 to 87%. The compounds 5a-5c were characterized by UV, FTIR, 1H-NMR, electrospray ionization mass spectrum spectra, and elemental analysis. Additionally, the absolute configurations of 5a-5c were determined by single crystal X-ray crystallography.
- Zhao, Jian,Shen, Guo-Ping,Shen, Xuan,Zhu, Dun-Ru,Zhang, Yu
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p. 1114 - 1119,6
(2020/09/16)
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- Facile preparation of aromatic esters from aromatic bromides with ethyl formate or DMF and molecular iodine via aryllithium
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Various aromatic bromides were treated with n-BuLi and subsequently with ethyl formate, followed by the reaction with ethanol and molecular iodine in the presence of K2CO3 to provide the corresponding aromatic ethyl esters in good yields. Moreover, aromatic bromides could be transformed into the corresponding aromatic methyl esters in good yields by the treatment with n-BuLi and subsequently with DMF, followed by the reaction with methanol, molecular iodine, and K2CO3. Some aromatics could be also converted into the corresponding aromatic esters in good yields by the treatment with n-BuLi, and subsequently with ethyl formate or DMF, followed by the reaction with molecular iodine and K2CO3. The present reactions offer a novel route for the transition-metal-free, carbon-monoxide-free, and therefore environmentally benign one-pot conversion of aromatic bromides and aromatics into aromatic esters.
- Ushijima, Sousuke,Moriyama, Katsuhiko,Togo, Hideo
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experimental part
p. 4701 - 4709
(2012/07/28)
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- MULTISUBSTITUTED AROMATIC COMPOUNDS AS INHIBITORS OF THROMBIN
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There are provided inter alia multisubstituted aromatic compounds useful for the inhibition of thrombin, which compounds include substituted pyrazolyl or substituted triazolyl. There are additionally provided pharmaceutical compositions. There are additionally provided methods of treating and preventing a disease or disorder, which disease or disorder is amenable to treatment or prevention by the inhibition of thrombin.
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Page/Page column 100
(2011/10/31)
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- Synthesis and antimicrobial evaluation of 1,3,4-oxadiazole-2-thione from some pyridine carboxylic acids
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The 5-(2-pyridyl)-1,3,4-oxadiazole-2-thione (4a) and the bis-5-(2,6-pyridyl)-1,3,4-oxadiazole-2-thione (4b) have been synthesized from the corresponding 2-pyridine carboxylic acid (picolinic acid) (1a) and 2,5-pyridine dicarboxylic acid (1b) by similar method. The esterification of the acids with ethyl and methyl alcohols gave the corresponding esters 2a and 2b. The hydrazides 3a and 3b were obtained in good yields. The 1,3,4-oxadiazoles 4a and 4b were formed by treatment of the corresponding hydrazides with CS 2 and KOH. The intermediates and the final products were characterized with IR, UV, 1H and 13C NMR and MS. The hydrazides 3a and 3b, the final products and the commercially available 5-(4-pyridyl)-1,3,4-oxadiazole-2-thione (5) were tested in vitro against the following micro organisms: Escherichia coli ATCC 25924, Pseudomonas aeruginosa ATCC 27853, Enterococcus faecalis ATTC 29212, Staphylococcus aureus ATCC 25923 and Pseudomonas fluorescens ATCC 17552 and compared with the known antibiotics Cephalosporin (cefotaxim) and Gentamycin. The results have shown that the synthesized compounds have appreciable effects. The bis-5-(2,6-pyridyl)-1,3,4- oxadiazole-2-thione (4b) had the highest effect upon all the tested microorganisms in general and on the gram-negative bacteria Pseudomonas fluorescens in particular, where its effect exceeded that of the well known Cephalosporin (cefotaxim).
- Benhammadi, Samia,Othman, Adil A.,Derdour, Aicha,Mami, Anas
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experimental part
p. 5535 - 5542
(2012/07/30)
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- Synthesis, biological evaluation, and molecular docking studies of 2-chloropyridine derivatives possessing 1,3,4-oxadiazole moiety as potential antitumor agents
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A series of new 2-chloropyridine derivatives possessing 1,3,4-oxadiazole moiety were synthesized. Antiproliferative assay results indicated that compounds 6o and 6u exhibited the most potent activity against gastric cancer cell SGC-7901, which was more potent than the positive control. Especially, compound 6o exhibited significant telomerase inhibitory activity (IC 50 = 2.3 ± 0.07 μM), which was comparable to the positive control ethidium bromide. Docking simulation was performed to position compound 6o into the active site of telomerase (3DU6) to determine the probable binding model.
- Zheng, Qing-Zhong,Zhang, Xiao-Min,Xu, Ying,Cheng, Kui,Jiao, Qing-Cai,Zhu, Hai-Liang
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scheme or table
p. 7836 - 7841
(2011/01/13)
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- Metal ion catalysis in nucleophilic substitution reaction of 4-nitrophenyl picolinate with alkali metal ethoxides in anhydrous ethanol
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Pseudo-first-order rate constants (kobsd) were measured spectrophotometrically for nucleophilic substitution reactions of 4-nitrophenyl picolinate (6) with alkali metal ethoxides (EtOM, M+ = K+, Na+ and Li+) in anhydrous ethanol at 25.0 ± 0.1 °C. The plot of kobsd vs. [EtOM] exhibits upward curvature regardless of the nature of M+ ions. However, the plot for the reaction of 6 with EtOK is linear with significantly decreased kobsd values when 18-crown-6-ether (18C6, a complexing agent for K+ ion) is added in the reaction medium. Dissection of kobsd into k EtO- and kEtOM (i.e., the second-order rate constant for the reaction with dissociated EtO- and ion-paired EtOM, respectively) has revealed that ion-paired EtOM is 3 ~ 17 times more reactive than dissociated EtO-. The reaction has been proposed to proceed through a 5-membered cyclic transition state, in which M+ ion increases the electrophilicity of the reaction site. Interestingly, Na+ ion exhibits the largest catalytic effect. The presence of a nitrogen atom in the pyridine moiety of 6 has been suggested to be responsible for the high Na + ion selectivity.
- Hong, Yeon-Ju,Kim, Song-I.,Um, Ik-Hwan
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experimental part
p. 2483 - 2487
(2011/01/12)
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- Formation of HoIII trinuclear clusters and GdIII monodimensional polymers induced by ortho and para regioisomers of pyridyl-functionalised a-diketones: Synthesis, structure, and magnetic properties
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Reaction of GdCl3(H2O)6 and 1,3-bis(pyridin-4-yl)propane-1,3-dione in methanol with an excess of triethylamine produced a monodimensional polymeric chain [Gd(p-dppd) 3-(H2O)]∞, whereas treatment of HoCl 3(H2O)6 with 1,3-bis(pyridin-2-yl)propane-1,3- dione yielded a trinuclear cluster [Ho3(o-dppd) 3(μ3-OH)2(H2O)4Cl 2]Cl2. The compounds were characterised by elemental analysis, IR spectroscopy and magnetism, and their structures were investigated by X-ray crystallography. The 8.20-μB magnetic-moment value of the polymeric [Gd(p-dppd)3(H2O)]∞, between 300 and 20 K, and the magnetisation isotherms (2-20 K; fields 0-5 T), are in agreement with essentially uncoupled single-ion Gd3+ f7 centres, a small decrease in μeff below 20 K being indicative of zero-field splitting. A temperature-dependent dc-susceptibility and magnetisation investigation of the trinuclear (tri-angular) [Ho 3(o-dppd)3(μ3-OH)2(H 2O)4Cl2]Cl2 revealed that spin-orbit and ligand-field effects on the Ho3+ centres, leading to thermal depopulation of Zeeman levels and consequent decreases in μeff values with decreasing temperature, are occurring rather than weak intra-cluster antiferromagnetic coupling. Frequency- and temperature-dependent acsusceptibility studies on this homometallic Ho3+ cluster did not show clear evidence for slow magnetisation reversal, characteristic of single-molecule magnetism (SMM), and this contrasts with such behaviour recently reported, elsewhere, for a Dy3+ triangle having the same core structure but with different chelating {O,O} ligands. Wiley-VCH Verlag GmbH & Co. KGaA, 2009.
- Andrews, Philip C.,Deacon, Glen B.,Frank, Rene,Fraser, Benjamin H.,Junk, Peter C.,MacLellan, Jonathan G.,Massi, Miliano,Moubaraki, Boujemaa,Murray, Keith S.,Silberstein, Morry
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experimental part
p. 744 - 751
(2009/06/05)
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- Therapeutic Compounds
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The invention provides a compound of formula I: wherein R1-R6, X, Y, and B have any of the values described herein, as well as salts of such compounds, compositions comprising such compounds, and therapeutic methods that comprise the administration of such compounds. The compounds are inhibitors of MAO-B enzyme function and are useful for improving cognitive function and for treating psychiatric disorders in animals.
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Page/Page column 54-55
(2010/11/28)
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- Synthesis and characterization of lanthanide complexes of 1-phenyl-3-methyl-5-hydroxy-4-pyrazolyl-phenyl ketone-2′-picolinoyl hydrazone
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The ligand, 1-phenyl-3-methyl-5-hydroxy-4-pyrazolyl phenyl ketone 2′-picolinoyl hydrazone (HL) is prepared by condensation of 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone with 2-picolinic acid hydrazide. Seven complexes of lanthanides with HL of the type [Ln(HL)3].2H2O (where Ln=trivalent lanthanides such as La, Ce, Nd, Sm, Gd, Dy and Er) have been synthesized and characterized by complexometric titration of lanthanoid ions, elemental analysis, molar conductance, IR. 1HNMR, electronic spectral studies and TGA analysis. IR spectra and thermogram shows the presence of two water moieties outside the coordination sphere and are non-electrolytic in nature. The complexes appear to be nine-coordinated and ligand act as a tridentate ligand.
- Thaker,Modi, Chetan K.
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p. 2544 - 2547
(2007/10/03)
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- Simple transformation of nitrile into ester by the use of chlorotrimethylsilane
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Treatment of nitriles with alcohol and chlorotrimethylsilane at 50°C for 4 h could give esters in fair to good yields. Under similar reaction conditions, intramolecular lactonization via the concomitant nitrile and hydroxy groups in good yield were also demonstrated.
- Luo, Fen-Tair,Jeevanandam, Arumugasamy
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p. 9455 - 9456
(2007/10/03)
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- Processes for producing 2-Halo-nicotinic acid derivatives and precursors thereto
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Disclosed are preferred processes for the preparation of 2-halo-nicotinic acid derivatives of formula (IV): STR1 by cyclocondensation of a 4-halo-4-cyanocarbonyl compound of formula (III): STR2 wherein X is Cl or Br; Y is a carbonyl group and R1, R2 and R3 are each, independently, H, Cl, Br or an organic radical. Further preferred aspects include the preparation of the above-noted 4-halo-4-cyanocarbonyl compound via Michael addition of a 2-halonitrile with an α,β-unsaturated aldehyde or ketone, and the preparation of the 2-halonitrile by redistribution of halogen between a 2,2-dihalonitrile and a parent nitrile.
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- Simple and mild method for preparation of α-pyridinecarboxylates and α-pyridyl ketones via trimethylstannyl derivatives
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Alkoxycarbonylation and acylation at the α-position of pyridine, quinoline, and isoquinoline via the respective trimethylstannyl derivatives were satisfactorily performed by employing ethyl chloroglyoxylate and acylformyl chloride under mild conditions.
- Yamamoto,Ouchi,Tanaka
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p. 1028 - 1030
(2007/10/03)
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- N-heteroarylium Salts in Synthesis, 3 Intramolecular ortho-Acylation of Some N-Heteroaromatic Ring Systems
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The title compounds 17 (prepared by methods A-C) have been reacted with sodium bis(trimethylsilyl)amide (18) in a heterogeneous mixture (-80 deg C, 2-60 h).The ortho-substituted N-heteroaromatic compounds 4 are isolated exclusively after an intramolecular and regiospecific reaction .This method represents the first widely applicable acylation technique for N-heteroaromatic compounds in which the incoming substituent (R1CO) functions as an internal electrophile and in which the formation of isomeric or polyacylated products has not yet been observed.Both experimental and theoretical (MNDO) investigations show that the substitution reaction (5) is primarily determined by the conformational and electronic properties of the deprotonation product 25 , which is formed preferentially.
- Anders, Ernst,Boldt, Hans Guenter,Clark, Timothy,Fuchs, Renate,Gassner, Thomas
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p. 279 - 296
(2007/10/02)
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