scholarly journals Acidic polymer containing sulfunic acid and carboxylic acid groups heterogenized with natural clay: A novel metal free and heterogeneous catalyst for acid-catalyzed reactions

Polyhedron ◽  
2020 ◽  
Vol 179 ◽  
pp. 114375 ◽  
Author(s):  
Samahe Sadjadi ◽  
Maryam Akbari ◽  
Fatemeh Ghoreyshi Kahangi ◽  
Majid M. Heravi
RSC Advances ◽  
2015 ◽  
Vol 5 (76) ◽  
pp. 61664-61670 ◽  
Author(s):  
Chottanahalli. S. Pavan Kumar ◽  
Kachigere. B. Harsha ◽  
Kempegowda Mantelingu ◽  
Kanchugarakoppal. S. Rangappa

The first one pot protocol for the diastereoselective synthesis of oxazolo[2,3-c]isoquinoline was achieved by metal-free, benzoic acid catalyzed reactions under mild conditions via C–H, C–O bond functionalization.


2020 ◽  
Vol 17 (7) ◽  
pp. 532-538
Author(s):  
Maryam Mirza-Aghayan ◽  
Mahdieh Molaee Tavana ◽  
Elaheh Golam Alipour Niazi ◽  
Rabah Boukherroub

An efficient, simple and regioselective ring-opening reaction of epoxides with various carboxylic acids under metal-free conditions is reported. The ring-opening of epoxides takes place in the presence of graphite oxide as an efficient and available catalyst to produce the corresponding 2-hydroxy monoester and 1,2-diester derivatives in good yields. Regioselective attack of the nucleophile, short reaction times, metal-free conditions and reusability of catalyst are among the advantages of the present protocol.


1986 ◽  
Vol 51 (10) ◽  
pp. 2167-2180 ◽  
Author(s):  
Lubor Fišera ◽  
Nadezhda D. Kozhina ◽  
Peter Oravec ◽  
Hans-Joachim Timpe ◽  
Ladislav Štibrányi ◽  
...  

3-Aryl-4-R-carbamoyl-5-hydroxymethylisoxazolines (IV) were synthesized by allowing R-NH2 amines with R = H, CH3, C3H7, C6H5C2H5, and NH2 to act on 3-(X-phenyl)-4-oxo-3a,4,6,6a-tetrahydrofuro[3,4-d]isoxazoles (III) with X = H, 4-CH3, 4-OCH3, 2-OCH3, 4-Cl, 2-Cl, 4-F, 2-F, 4-Br, 4-NO2, and 3-NO2. Exposed to radiation, the substances IV give Z-2-hydroxymethylamino-2-aryl-1-formylacrylamides (V) in good yields. The 4-Cl and 4-F substituted Z-derivatives V isomerize irreversibly to the E-derivatives VI if allowed to stand in solvent; the remaining derivatives V are stable. The quantum yields of the photoreaction are from 0.012 to 0.106 in dependence on the substituent X. In all cases where the compounds IV were used for the preparation of condensed heterocycles in conditions of acid-catalyzed reactions, lactones III were preferentially formed; the action of thionyl chloride on IV results in the formation of chloromethyl derivatives VIII, which do not undergo further cyclization.


Author(s):  
Mizzanoor Rahaman ◽  
M. Shahnawaz Ali ◽  
Khorshada Jahan ◽  
Damon Hinz ◽  
Jawad Bin Belayet ◽  
...  

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 502
Author(s):  
Hanene Belkahla ◽  
Andrei Alexandru Constantinescu ◽  
Tijani Gharbi ◽  
Florent Barbault ◽  
Alexandre Chevillot-Biraud ◽  
...  

Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) is a member of the TNF cytokine superfamily. TRAIL is able to induce apoptosis through engagement of its death receptors DR4 and DR5 in a wide variety of tumor cells while sparing vital normal cells. This makes it a promising agent for cancer therapy. Here, we present two different ways of covalently grafting TRAIL onto maghemite nanoparticles (NPs): (a) by using carboxylic acid groups of the protein to graft it onto maghemite NPs previously functionalized with amino groups, and (b) by using the amino functions of the protein to graft it onto NPs functionalized with carboxylic acid groups. The two resulting nanovectors, NH-TRAIL@NPs-CO and CO-TRAIL@NPs-NH, were thoroughly characterized. Biological studies performed on human breast and lung carcinoma cells (MDA-MB-231 and H1703 cell lines) established these nanovectors are potential agents for cancer therapy. The pro-apoptotic effect is somewhat greater for CO-TRAIL@NPs-NH than NH-TRAIL@NPs-CO, as evidenced by viability studies and apoptosis analysis. A computational study indicated that regardless of whether TRAIL is attached to NPs through an acid or an amino group, DR4 recognition is not affected in either case.


Author(s):  
Emanuele Moioli ◽  
Leo Schmid ◽  
Peter Wasserscheid ◽  
Hannsjoerg Freund

The kinetics of the acid catalyzed reactions of acetaldehyde ammonia trimer (AAT) and paraldehyde (para) to 2-methyl-5-ethyl pyridine (MEP) in the presence of an acid catalyst were investigated systematically. A...


Catalysts ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 1 ◽  
Author(s):  
Jie Zhang ◽  
Zhiming Zhang ◽  
Fulin Yang ◽  
Haoke Zhang ◽  
Jingzhi Sun ◽  
...  

Novel polymerizations based on alkyne monomers are becoming a powerful tool to construct polymers with unique structures and advanced functions in the areas of polymer and material sciences, and scientists have been attracted to develop a variety of novel polymerizations in recent decades. Therein, catalytic systems play an indispensable role in the influence of polymerization efficiencies and the performances of the resultant polymers. Concerning the shortcomings of metallic catalysts, much of the recent research focus has been on metal-free polymerization systems. In this paper, metal-free catalysts are classified and the corresponding polymerizations are reviewed, including organobase-catalyzed polymerizations, Lewis-acid-catalyzed polymerizations, as well as catalyst-free polymerizations. Moreover, the challenges and perspectives in this area are also briefly discussed.


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