Unexpected Selectivity in Cyclotetrasiloxane Formation by the Hydrolytic Condensation Reaction of Trichloro(phenyl)silane

2016 ◽  
Vol 2016 (18) ◽  
pp. 2882-2886 ◽  
Author(s):  
Fujio Yagihashi ◽  
Masayasu Igarashi ◽  
Yumiko Nakajima ◽  
Kazuhiko Sato ◽  
Yoshiyuki Yumoto ◽  
...  
2010 ◽  
Vol 7 (2) ◽  
pp. 67
Author(s):  
Mohd Abdul Fatah Abdul Manan ◽  
Hadariah Bahron ◽  
Karimah Kassim ◽  
Mohd Asrul Hafaz Mohamad ◽  
Syed Nazmi Sayed Mohamad

A novel Schiff base containing nitrogen-oxygen-sulfur (NOS) donor atoms formed from the condensation reaction of S-2,4-dichlorobenzyldithiocarbazate (S-2,4BDTC) with 5-fluroisatin has been synthesized. Complexes of cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) with this Schiff base have been prepared and characterized using elemental analysis and various physico-chemical techniques. In the cobalt(II) and nickel(II) complexes the Schiff base behaves as a uninegatively charged tridentate nitrogen-oxygen-sulfur (NOS) chelating ligand, bonding through the azomethine nitrogen, thiolate sulfur and carbonylic oxygen of the isatin moiety. However, in the copper(II), zinc(II) and cadmium(II) complexes the Schiff base behaves as a nitrogen-sulfur (NS) bidentate chelating ligand, bonding through the azomethine nitrogen and thiolate sulfur. The Schiff base and the metal complexes were evaluated with respect to antimicrobial activity, which was performed in relation to two selected pathogenic microbials (Bacillus subtilis and Pseudomonas aeruginosa). It was observed that only the zinc Schiff base complex exhibited strong activity against the Bacillus subtilis bacteria with an inhibition zone of 25 mm. 


2010 ◽  
Vol 7 (2) ◽  
pp. 67
Author(s):  
Mohd Abdul Fatah Abdul Manan ◽  
Hadariah Bahron ◽  
Karimah Kassim ◽  
Mohd Asrul Hafiz Muhamad ◽  
Syed Nazmi Sayed Mohamad

A novel Schiff base containing nitrogen-oxygen-sulfur (NOS) donor atoms formed from the condensation reaction of S-2,4- dichlorobenzyldithiocarbazate (S-2.4BDTC) with 5-fluroisatin has been synthesized. Complexes of cobalt(ll), nickel(ll), copper(ll), zinc(ll) and cadmium(ll) with this Schiff base have been prepared and characterized using elemental analysis and various physico-chemical techniques. In the cobalt(ll) and nickel(II) complexes the SchifJbase behaves as a uninegatively charged tridentate nitrogen-oxygen-sulfur (NOS) chelating ligand, bonding through the azomethine nitrogen, thiolate sulfur and carbonylic oxygen of the isatin moiety. However. in the copper(ll), zinc(II) and cadmium(II) complexes the Schiff base behaves as a nitrogen-sulfur (NS) bidentate chelating ligand, bonding through the azomethine nitrogen and thiolate sulfur. The Schiff base and the metal complexes were evaluated with respect to antimicrobial activity, which was performed in reallion to two selected pathogenic microbials (Bacillus subtilis and Pseudomonas aeruginosa). It was observed that only the zinc Schiffbase complex exhibited strong activity against the Bacillus subtilis bacteria with an inhibition zone of25 mm.


Author(s):  
Birgit Meindl ◽  
Katharina Pfennigbauer ◽  
Berthold Stöger ◽  
Martin Heeney ◽  
Florian Glöcklhofer

Anthracene derivatives have been used for a wide range of applications and many different synthetic methods for their preparation have been developed. However, despite continued synthetic efforts, introducing substituents in some positions has remained difficult. Here we present a method for the synthesis of 2,3,6,7-substituted anthracene derivatives, one of the most challenging anthracene substitution patterns to obtain. The method is exemplified by the preparation of 2,3,6,7-anthracenetetracarbonitrile and employs a newly developed, stable protected 1,2,4,5-benzenetetracarbaldehyde as the precursor. The precursor can be obtained in two scalable synthetic steps from 2,5-dibromoterephthalaldehyde and is converted into the anthracene derivative by a double intermolecular Wittig reaction under very mild conditions followed by a deprotection and intramolecular double ring-closing condensation reaction. Further modification of the precursor is expected to enable the introduction of additional substituents in other positions and may even enable the synthesis of fully substituted anthracene derivatives by the presented approach.<br>


2020 ◽  
Author(s):  
Takayuki Tonoi ◽  
Miyuki Ikeda ◽  
Teruyuki Sato ◽  
Ryo Kawahara ◽  
Takatsugu Murata ◽  
...  

<div>An efficient and practical method for the synthesis of (9R,14R,17R)-FE399, a novel antitumor bicyclic depsipeptide, was developed. A 2-methyl-6-nitrobenzoic anhydride (MNBA)-mediated dehydration condensation reaction was effectively employed for the formation of the 16-membered macrocyclic depsipeptide moiety of FE399. FE399 was found to exist as an inseparable equilibrium mixture of conformational isomers; the mixture was quantitatively transformed into the corresponding S-benzyl product and isolated as a single isomer. Thus, we could confirm that the molecular structure of FE399 obtained by this method is identical to that of the natural product.</div>


2018 ◽  
Author(s):  
Jaya Prakash Madda ◽  
Pilli Govindaiah ◽  
Sushant Kumar Jena ◽  
Sabbhavat Krishna ◽  
Rupak Kishor

<p>Covalent organic Imine polymers with intrinsic meso-porosity were synthesized by condensation reaction between 4,4-diamino diphenyl methane and (para/meta/ortho)-phthaladehyde. Even though these polymers were synthesized from precursors of bis-bis covalent link mode, the bulk materials were micrometer size particles with intrinsic mesoporous enables nitrogen as well as carbon dioxide adsorption in the void spaces. These polymers were showed stability up to 260<sup>o</sup> centigrade. Nitrogen gas adsorption capacity up to 250 cc/g in the ambient pressure was observed with type III adsorption characteristic nature. Carbon dioxide adsorption experiments reveal the possible terminal amine functional group to carbamate with CO<sub>2</sub> gas molecule to the polymers. One of the imine polymers, COP-3 showed more carbon dioxide sorption capacity and isosteric heat of adsorption (Q<sub>st</sub>) than COP-1 and COP-2 at 273 K even though COP-3 had lower porosity for nitrogen gas than COP-1 and COP-2. We explained the trends in gas adsorption capacities and Qst values as a consequence of the intra molecular interactions confirmed by Density Functional Theory computational experiments on small molecular fragments.</p>


2019 ◽  
Author(s):  
Chem Int

A multifunctional ligand derivative of pyrrolidone has been synthesized by condensation reaction between 4-aminoantipyrine and 2-pyrrolidinone. The ligand and its Iron(II) complex were characterized using physical method and UV and IR techniques. The ligand and Fe(II) complex were tested against broad spectrums of bacterial organisms and the results show that both the ligand and complex were active against various organisms tested.


2018 ◽  
Vol 21 (4) ◽  
pp. 298-301 ◽  
Author(s):  
Ghasem Marandi

Aim and Objective: The reaction of cyclohexylisocyanide and 2-aminopyridine-3- carboxylic acid in the presence of benzaldehyde derivatives in ethanol led to 3-(cyclohexylamino)-2- arylimidazo[1,2-a]pyridine-8-carboxylic acids in high yields. In a three component condensation reaction, isocyanide reacts with 2-aminopyridine-3-carboxylic acid and aromatic aldehydes without any prior activation. Material and Methods: The synthesized products have stable structures which have been characterized by IR, 1H, 13C and Mass spectroscopy as well as CHN-O analysis. Results: In continuation of our attempts to develop simple one-pot routes for the synthesis of 3- (cyclohexylamino)-2-arylimidazo[1,2-a]pyridine-8-carboxylic acids, aromatic aldehydes with divers substituted show a high performance. Conclusion: In conclusion, this study introduces the art of combinatorial chemistry using a simple one-pot procedure for the synthesis of new materials which are interesting compounds in medicinal and biological sciences.


2019 ◽  
Vol 15 ◽  
Author(s):  
Thais Batista Fernandes ◽  
Natanael Dante Segretti ◽  
Felipe Rebello Lourenço ◽  
Thalita Marcílio Cândido ◽  
André Rolim Baby ◽  
...  

Background: Antimicrobial resistance is a persistent problem about infections treatment and carries needing for develop new antimicrobial agents. Inhibiting of bacterial β-ketoacyl acyl carrier protein synthase III (FabH), which catalyzes the condensation reaction between a CoA-attached acetyl group and an ACP-attached malonyl group in bacteria is an interesting strategy to find new antibacterial agents. Objective: The aim of this work was to design and synthesize arylsulfonylhydrazones potentially FabH inhibitors and evaluate their antimicrobial activity. Methods: MIC50 of sulfonylhydrazones against E. coli and S. aureus was determined. Antioxidant activity was evaluated by DPPH (1-1’-diphenyl-2-picrylhydrazyl) assay and cytotoxicity against LL24 lung fibroblast cells was verified by MTT method. Principal component analysis (PCA) was performed in order to suggest a structure-activity relationship. Molecular docking allowed to propose sulfonylhydrazones interactions with FabH. Results: The most active compound showed activity against S. aureus and E. coli, with MIC50 = 0.21 and 0.44 µM, respectively. PCA studies correlated better activity to lipophilicity and molecular docking indicated that sulfonylhydrazone moiety is important to hydrogen-bond with FabH while methylcatechol ring performs π-π stacking interaction. The DPPH assay revealed that some sulfonylhydrazones derived from the methylcatechol series had antioxidant activity. None of the evaluated compounds was cytotoxic to human lung fibroblast cells, suggesting that the compounds might be considered safe at the tested concentration. Conclusion: Arylsufonylhydrazones is a promising scaffold to be explored for design of new antimicrobial agents.


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