Thermal Stability, Kinetic Degradation and Lifetime Prediction of Chitosan Schiff Bases Derived from Aromatic Aldehydes

2021 ◽  
Vol 6 (3) ◽  
pp. 306-317
Author(s):  
Lahcen El Hamdaoui ◽  
Maryam El Marouani ◽  
Mehdi El Bouchti ◽  
Fatima Kifani‐Sahban ◽  
Mohammed El Moussaouiti
2020 ◽  
Vol 20 (18) ◽  
pp. 1929-1941
Author(s):  
Heba A. Elhady ◽  
Hossa F. Al-Shareef

Background and Objective: Due to the well-documented anti-proliferative activity of 2-thiohydantoin incorporated with pyrazole, oxadiazole, quinazoline, urea, β-naphthyl carbamate and Schiff bases, they are noteworthy in pharmaceutical chemistry. Methods: An efficient approach for the synthesis of a novel series of 2-thiohydantoin derivatives incorporated with pyrazole and oxadiazole has proceeded via the reaction of the acyl hydrazide with chalcones and/or triethyl orthoformate. Schiff bases were synthesized by the reaction of the acyl hydrazide with different aromatic aldehydes. Moreover, Curtius rearrangement was applied to the acyl azide to obtain the urea derivative, quinazoline derivative, and carbamate derivative. Results: The synthesized compounds structures were discussed and confirmed depending on their spectral data. The anticancer activity of these heterocyclic compounds was evaluated against the breast cancer cell line (MCF-7), where they showed variable activity. Compound 5d found to have a superior anticancer activity, where it has (IC50 = 2.07 ± 0.13 μg/mL) in comparison with the reference drug doxorubicin that has (IC50 = 2.79 ± 0.07 μg / mL). Then compound 5d subjected to further studies such as cell cycle analysis and apoptosis. Apoptosis was confirmed by the upregulation of Bax, downregulation of Bcl-2, and the increase of the caspase 3/7percentage. Conclusion: Insertion of pyrazole, oxadiazole and, quinazoline moieties with 2-thiohydantoin moiety led to the enhancement of its anti-proliferative activity. Hence they can be used as anticancer agents.


Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4160
Author(s):  
Speranta Avram ◽  
Ana Maria Udrea ◽  
Diana Camelia Nuta ◽  
Carmen Limban ◽  
Adrian Cosmin Balea ◽  
...  

(1) Background: The research aims to find new treatments for neurodegenerative diseases, in particular, Alzheimer’s disease. (2) Methods: This article presents a bioinformatics and pathology study of new Schiff bases, (EZ)-N′-benzylidene-(2RS)-2-(6-chloro-9H-carbazol-2-yl)propanehydrazide derivatives, and aims to evaluate the drug-like, pharmacokinetic, pharmacodynamic and pharmacogenomic properties, as well as to predict the binding to therapeutic targets by applying bioinformatics, cheminformatics and computational pharmacological methods. (3) Results: We obtained these Schiff bases by condensing (2RS)-2-(6-chloro-9H-carbazol-2-yl)propanehydrazide with aromatic aldehydes, using the advantages of microwave irradiation. The newly synthesized compounds were characterized spectrally, using FT-IR and NMR spectroscopy, which confirmed their structure. Using bioinformatics tools, we noticed that all new compounds are drug-likeness features and may be proposed as potentially neuropsychiatric drugs (4) Conclusions: Using bioinformatics tools, we determined that the new compound 1e had a high potential to be used as a good candidate in neurodegenerative disorders treatment.


1973 ◽  
Vol 19 (6) ◽  
pp. 1666-1668
Author(s):  
V. P. Panov ◽  
A. K. Trukhmanov ◽  
R. G. Zhbankov

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Fubin Wan ◽  
Xun Chen ◽  
Zhenhua Jiang ◽  
Yinong Wu

This paper presents the operation status and results of ground thermal cycling test of pulse tube refrigerators (PTRs) for space application. Firstly, a thermal cycling degradation model was proposed by considering two physical mechanisms: contamination and fatigue damage. Then, a thermal cycling test scheme of two types of PTRs was designed and performed to demonstrate their long lifetime and high thermal stability. Two type A PTRs with cooling capacity of 1W@60 K and two type B PTRs with cooling capacity of 5W@80 K were continuously operated for about two years in a simulated vacuum thermal cycling environment. Effects of heat rejection temperature variation on thermal stability and dynamic performance of the PTRs were investigated. Furthermore, the thermal cycling degradation model was validated with the actual thermal cycling test data. Finally, the predicted pseudo-failure lifetime was acquired via experimental data and degradation model. Moreover, the estimated reliability of PTRs was obtained through using the Weibull distribution. The proposed thermal cycling test scheme and innovative lifetime prediction and reliability estimation method provide a quick and accurate approach for the cooler manufacturer to assess the lifetime and reliability of the space PTRs.


2006 ◽  
Vol 2006 ◽  
pp. 1-10 ◽  
Author(s):  
Ram K. Agarwal ◽  
Lakshman Singh ◽  
Deepak Kumar Sharma

We have synthesized a novel series of Schiff bases by condensation of 4-aminoantipyrine and various aromatic aldehydes followed by reaction with thiosemicarbazide. These thiosemicarbazones are potential ligands toward transition metal ions. The reaction of copper(II) salts with 4[N-(benzalidene)amino]antipyrinethiosemicarbazone (BAAPTS), 4[N-(4′-methoxybenzalidene) amino] antipyrinethiosemicarbozone (MBAAPTS), 4[N-(4′-dimethylamino benzalidene) amino] antipyrinethiosemicarbazone (DABAAPTS), and 4[N-(cinnamalidene) amino] antipyrinethiosemicarbazone (CAAPTS) resulted in the formation of solid complexes with the general compositionCuX2⋅(H2O)(L)(X = Cl, Br,NO3, NCS, orCH3COO; L = BAAPTS, MBAAPTS, DABAAPTS, or CAAPTS). These complexes were characterized through elemental analysis, molecular weight, electrical conductance, infrared, electronic spectra, and magnetic susceptibilities at room temperature. Copper(II) complexes with BAAPTS and MBAAPTS were screened for antibacterial and antifungal properties and have exhibited potential activity. Thermal stabilities of two representative complexes were also investigated.


2015 ◽  
Vol 68 (6) ◽  
pp. 919 ◽  
Author(s):  
Jianping Wei ◽  
Fangmei Li ◽  
Junhui Xu ◽  
Xinhua Peng

New polynitrostilbenes were directly synthesised by the Knoevenagel condensation of aromatic aldehydes with nitrotoluenes. The differential scanning calorimetry results demonstrated that the introduction of an amino group and C=C double bonds could improve the thermal stability.


2014 ◽  
Vol 2 (27) ◽  
pp. 10424-10434 ◽  
Author(s):  
Vinay Jaiswal ◽  
Kalyani Kalyani ◽  
Rashmi B. Rastogi ◽  
Rajesh Kumar

Tribological performance of sulfur, phosphorous and metal-free Schiff bases and their synergistic formulations with borate ester in paraffin oil has been evaluated using a four-ball tester at optimized concentrations (1% w/v).


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