Unexpected formation of π-expanded isoquinoline from anthracene possessing four electron-donating groups via the Duff reaction

Marek K. Węcławski; Irena Deperasińska; Arkadiusz Leniak; Marzena Banasiewicz; Bolesław Kozankiewicz; Daniel T. Gryko

doi:10.1039/c6ob00981f

ChemInform Abstract: Unexpected Formation of π-Expanded Isoquinoline from Anthracene Possessing Four Electron-Donating Groups via the Duff Reaction.

ChemInform ◽

10.1002/chin.201649156 ◽

2016 ◽

Vol 47 (49) ◽

Author(s):

Marek K. Weclawski ◽

Irena Deperasinska ◽

Arkadiusz Leniak ◽

Marzena Banasiewicz ◽

Boleslaw Kozankiewicz ◽

...

Keyword(s):

Unexpected Formation ◽

Duff Reaction ◽

Electron Donating Groups

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Nε-Acetyl L-α Lysine Improves Activity and Stability of α-Amylase at Acidic Conditions: A Comparative Study with other Osmolytes

Protein and Peptide Letters ◽

10.2174/0929866526666191105130041 ◽

2020 ◽

Vol 27 (6) ◽

pp. 551-556

Author(s):

Nidhya N. Joghee ◽

Gurunathan Jayaraman ◽

Masilamani Selladurai

Keyword(s):

Enzyme Activity ◽

Amino Acid ◽

Thermodynamic Stability ◽

Protective Effects ◽

Residual Enzyme Activity ◽

Functional Stability ◽

Biotechnological Applications ◽

Optimal Temperature ◽

Acidic Conditions ◽

Cellular Components

Background: Nε-acetyl L-α lysine is an unusual acetylated di-amino acid synthesized and accumulated by certain halophiles under osmotic stress. Osmolytes are generally known to protect proteins and other cellular components under various stress conditions. Objective: The structural and functional stability imparted by Nε-acetyl L-lysine on proteins were unknown and hence was studied and compared to other commonly known bacterial osmolytes - ectoine, proline, glycine betaine, trehalose and sucrose. Methods: Effects of osmolytes on the temperature and pH profiles, pH stability and thermodynamic stability of the model enzyme, α-amylase were analyzed. Results: At physiological pH, all the osmolytes under study increased the optimal temperature for enzyme activity and improved the thermodynamic stability of the enzyme. At acidic conditions (pH 3.0), Nε-acetyl L-α lysine and ectoine improved both the catalytic and thermodynamic stability of the enzyme; it was reflected in the increase in residual enzyme activity after incubation of the enzyme at pH 3.0 for 15 min by 60% and 63.5% and the midpoint temperature of unfolding transition by 11°C and 10°C respectively. Conclusion: Such significant protective effects on both activity and stability of α-amylase imparted by addition of Nε-acetyl L-α lysine and ectoine at acidic conditions make these osmolytes interesting candidates for biotechnological applications.

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Microwave Assisted Synthesis and Antifungal Activity of Some Novel Thioethers Containing 1,2,4-triazolo[4,3-a] pyridine Moiety

Letters in Drug Design & Discovery ◽

10.2174/157018081306160618181757 ◽

2016 ◽

Vol 13 (6) ◽

pp. 521-525 ◽

Cited By ~ 25

Author(s):

Zhi-Wen Zhai ◽

Yan-Xia Shi ◽

Ming-Yan Yang ◽

Wen Zhao ◽

Zhao-Hui Sun ◽

...

Keyword(s):

Antifungal Activity ◽

Microwave Assisted Synthesis ◽

Microwave Assisted ◽

Pyridine Moiety

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Structure-Activity Relationship and Antimicrobial Evaluation of N-Phenylpyrazole Curcumin Derivatives

Current Bioactive Compounds ◽

10.2174/1573407215666190124115010 ◽

2020 ◽

Vol 16 (4) ◽

pp. 481-488

Author(s):

Heli Sanghvi ◽

Satyendra Mishra

Keyword(s):

Antibacterial Activity ◽

Gram Negative Bacteria ◽

Pyrazole Derivatives ◽

Gram Positive ◽

Gram Negative ◽

E Coli ◽

Curcumin Derivatives ◽

Structure Activity ◽

Electron Donating Groups ◽

Derivatives Of

Background: Curcumin, one of the most important pharmacologically significant natural products, has gained significant consideration among scientists for decades since its multipharmacological activities. 1, 3-Dicarbonyl moiety of curcumin was found to be accountable for the rapid degradation of curcumin molecule. The aim of present work is to replace 1, 3-dicarbonyl moiety of curcumin by pyrazole and phenylpyrazole derivatives with a view to improving its stability and to investigate the role of substitution in N-phenylpyrazole curcumin on its antibacterial activity against both Gram-positive as well as Gram-negative bacteria. Methods: Pyrazole derivatives of curcumin were prepared by heating curcumin with phenyhydrazine/ substituted phenyhydrazine derivatives in AcOH. The residue was purified by silica gel column chromatography. Structures of purified compounds were confirmed by 1H NMR and Mass spectroscopy. The synthesized compounds were evaluated for their antibacterial activity by the microdilution broth susceptibility test method against gram positive (S. aureus) and gram negative (E. coli). Results: Effects of substitution in N-phenylpyrazole curcumin derivatives against S. aureus and E. coli were studied. The most active N-(3-Nitrophenylpyrazole) curcumin (12) exhibits twenty-fold more potency against S. aureus (MIC: 10μg/mL)) and N-(2-Fluoroophenylpyrazole) curcumin (5) fivefold more potency against E. coli (MIC; 50 μg/mL) than N-phenylpyrazole curcumin (4). Whereas, a remarkable decline in anti-bacterial activity against S. aureus and E. coli was observed when electron donating groups were incorporated in N-phenylpyrazole curcumin (4). Comparative studies of synthesized compounds suggest the effects of electron withdrawing and electron donating groups on unsubstituted phenylpyrazole curcumin (4). Conclusion: The structure-activity relationship (SAR) results indicated that the electron withdrawing and electron donating at N-phenylpyrazole curcumin played key roles for their bacterial inhibitory effects. The results of the antibacterial evaluation showed that the synthesized pyrazole derivatives of curcumin displayed moderate to very high activity in S. aureus. In conclusion, the series of novel curcumin derivatives were designed, synthesized and tested for their antibacterial activities against S. aureus and E. coli. Among them, N-(3-Nitrophenylpyrazole curcumin; 12) was most active against S. aureus (Gram-positive) and N-(2-Fluoroophenylpyrazole) curcumin (5) against E. coli (Gram-negative) bacteria.

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Preparation of Organized Mesoporous Silica from Sodium Metasilicate Solutions in Alkaline Medium Using Nonionic Surfactants

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc20032019 ◽

2003 ◽

Vol 68 (10) ◽

pp. 2019-2031 ◽

Cited By ~ 1

Author(s):

Markéta Zukalová ◽

Jiří Rathouský ◽

Arnošt Zukal

Keyword(s):

Mesoporous Silica ◽

Ethylene Oxide ◽

Sodium Metasilicate ◽

Spherical Particles ◽

Structure Directing Agent ◽

Inorganic Species ◽

Poly Ethylene Oxide ◽

Acidic Conditions ◽

Poly Ethylene ◽

Hydrolysis Of

A new procedure has been developed, which is based on homogeneous precipitation of organized mesoporous silica from an aqueous solution of sodium metasilicate and a nonionic poly(ethylene oxide) surfactant serving as a structure-directing agent. The decrease in pH, which induces the polycondensation of silica, is achieved by hydrolysis of ethyl acetate. Owing to the complexation of Na+ cations by poly(ethylene oxide) segments, assembling of the mesostructure appears to occur under electrostatic control by the S0Na+I- pathway, where S0 and I- are surfactant and inorganic species, respectively. As the complexation of Na+ cations causes extended conformation of poly(ethylene oxide) segments, the pore size and pore volume of organized mesoporous silica increase in comparison with materials prepared under neutral or acidic conditions. The assembling of particles can be fully separated from their solidification, which results in the formation of highly regular spherical particles of mesoporous silica.

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The Hsp60 Protein of Helicobacter Pylori Exhibits Chaperone and ATPase Activities at Elevated Temperatures

BioChem ◽

10.3390/biochem1010002 ◽

2021 ◽

Vol 1 (1) ◽

pp. 19-25

Author(s):

Jose A. Mendoza ◽

Julian L. Ignacio ◽

Christopher M. Buckley

Keyword(s):

Helicobacter Pylori ◽

Heat Stress ◽

Molecular Chaperone ◽

Elevated Temperatures ◽

Citrate Synthase ◽

Gastric Epithelium ◽

Acidic Conditions ◽

H Pylori ◽

Induced Aggregation ◽

Hydrolysis Of

The heat-shock protein, Hsp60, is one of the most abundant proteins in Helicobacter pylori. Given its sequence homology to the Escherichia coli Hsp60 or GroEL, Hsp60 from H. pylori would be expected to function as a molecular chaperone in this organism. H. pylori is a type of bacteria that grows on the gastric epithelium, where the pH can fluctuate between neutral and 4.5, and the intracellular pH can be as low as 5.0. We previously showed that Hsp60 functions as a chaperone under acidic conditions. However, no reports have been made on the ability of Hsp60 to function as a molecular chaperone under other stressful conditions, such as heat stress or elevated temperatures. We report here that Hsp60 could suppress the heat-induced aggregation of the enzymes rhodanese, malate dehydrogenase, citrate synthase, and lactate dehydrogenase. Moreover, Hsp60 was found to have a potassium and magnesium-dependent ATPase activity that was stimulated at elevated temperatures. Although, Hsp60 was found to bind GTP, the hydrolysis of this nucleotide could not be observed. Our results show that Hsp60 from H. pylori can function as a molecular chaperone under conditions of heat stress.

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Polyoxometalate based ionic crystal: dual applications in selective colorimetric sensor for hydrated ZnCl2 and antimicrobial activity

New Journal of Chemistry ◽

10.1039/d1nj00138h ◽

2021 ◽

Vol 45 (12) ◽

pp. 5576-5588

Author(s):

C. Sabarinathan ◽

M. Karthikeyan ◽

R. M. Murugappan ◽

Savarimuthu Philip Anthony ◽

Bhaskaran Shankar ◽

...

Keyword(s):

Antimicrobial Activity ◽

Ionic Crystal ◽

Colorimetric Sensor ◽

Icp Oes ◽

One Pot ◽

One Pot Synthesis ◽

Acidic Conditions

One-pot synthesis of POM-salt ([Himi]4[SiMo12O40] (1)) was achieved by mixing silicomolybdic acid and imidazole in acidic conditions and characterized by FTIR, TGA, SEM, EDX, ICP-OES and XPS.

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Prediction of Sodium Substitution Sites in Octacalcium Phosphate: The Relationships of Ionic Pair Ratios in Reacting Solutions

Ceramics ◽

10.3390/ceramics4020018 ◽

2021 ◽

Vol 4 (2) ◽

pp. 240-248

Author(s):

Yuki Sugiura ◽

Masanori Horie

Keyword(s):

Dicarboxylic Acid ◽

Experimental Studies ◽

Ionic Species ◽

Octacalcium Phosphate ◽

Pair Formation ◽

Formation Processes ◽

Ionic Pair ◽

Substitution Process ◽

Sodium Substitution ◽

Acidic Conditions

Octacalcium phosphate (OCP) is widely used in biomaterial fabrication by virtue of its unique crystal structure and low environmental loading. Although various ion and molecule substitution methods into the OCP unit lattice have been introduced, it remains unclear which factors and mechanisms dominate the substitution process. Experimental studies have indicated that Na alkali metal ions are substituted at the P3 PO4 conjugated site in acidic to weakly acidic conditions and the P5 PO4 conjugated site in neutral to weak basic conditions. Ionic species calculation methods have indicated that the pair ratios of Na and HPO42− (NaHPO4−) are small in acidic reacting solutions but large under weakly basic conditions. Consequently, the roles played by NaHPO4− and ionic pair formation processes are thought to dominate ion and molecule substitution into the OCP unit lattice. Such ionic pair formation strongly inhibits dicarboxylic acid substitution into the OCP unit lattice due to the replacement of the Ca ion, which conjugates P5 PO4 as an anchor of dicarboxylic acid.

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4-vinylpyridine derivatives: Protonation, methylation and silver(I) coordination chemistry

Journal of Chemical Research ◽

10.1177/1747519821989659 ◽

2021 ◽

pp. 174751982198965

Author(s):

Guoqi Zhang

Keyword(s):

Mass Spectrometry ◽

Schiff Base ◽

Coordination Chemistry ◽

Elemental Analysis ◽

Silver Complex ◽

Spectroscopic Techniques ◽

X Ray ◽

X Ray Crystallography ◽

Pyridine Moiety ◽

New Compounds

( E)-4-[2-(Pyridin-4-yl)vinyl]benzaldehyde, containing both a 4-vinylpyridine and an aldehyde functionality, is utilized to develop new, highly conjugated chalcone compounds and a bis-Schiff base azine compound. The chalcone-containing compounds are further explored for their protonation, methylation and silver(I) coordination chemistry using the pyridine moiety. In parallel, a cyano-containing analogue, ( E)-4-[2-(pyridin-4-yl)vinyl]benzonitrile is also synthesized and studied for its silver(I) coordination chemistry. These new compounds are fully characterized by mass spectrometry, elemental analysis and spectroscopic techniques. The methylated product of ( E)-1-(9-anthryl)-3-{4-[2-(pyridin-4-yl)vinyl]phenyl}prop-2-en-1-one and a silver complex of ( E)-4-[2-(pyridin-4-yl)vinyl]benzonitrile are structurally determined by X-ray crystallography.

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