Mixed Ligand Complexes of Oxovanadium (IV) Oxalate

The oxovanadium(IV) complexes VOC₂O₄ · 2DMF, VOC₂O₄ · 2 formamide, VOC₂O₄ · 2 ethylene urea, VOC₂O₄ · 2 urea and VOC₂O₄ · en have been prepared and characterized. The oxalato group functions as a bidentate ligand in all these complexes. Except ethylene diamine the remaining ligands – DMF. formamide, ethylene urea and urea – act as monodentate ligand coordinating through their carbonyl oxygen. Ethylene diamine is bound to the metal through nitrogen. In all the complexes vanadium is five coordinated in distorted tetragonal-pyramidal structures.     

Synthesis and characterization of a nano‐hydroxyapatite/chitosan/polyethylene glycol nanocomposite for bone tissue engineering

A novel nanocomposite involving nano‐hydroxyapatite/chitosan/polyethylene glycol (n‐HAP/CS/PEG) has been successfully synthesized via co‐precipitation approach at room temperature. The purpose to synthesize such nanocomposite is to search for an ideal analogue which may mimick the composition of natural bone for bone tissue engineering with respect to suitable biocompatibility, cytotoxicity and mechanical properties. The FTIR spectra of n‐HAP/CS and n‐HAP/CS/PEG scaffolds indicated significant intermolecular interaction between the various components of both the nanocomposites. The results of XRD, TEM and TGA/DTA suggested that the crystallinity and thermal stability of the n‐HAP/CS/PEG scaffold have decreased and increased respectively, relative to n‐HAP/CS scaffold. The comparison of SEM images of both the scaffolds indicated that the incorporation of PEG influenced the surface morphology while a better in‐vitro bioactivity has been observed in n‐HAP/CS/PEG than in n‐HAP/CS based on SBF study, referring a greater possibility for making direct bond to living bone if implanted. Furthermore, MTT assay revealed superior non‐toxic nature of n‐HAP/CS/PEG to murine fibroblast L929 cells as compared to n‐HAP/CS. The comparative swelling studies of n‐HAP/CS/PEG and n‐HAP/CS scaffolds revealed a better swelling rate for n‐HAP/CS/PEG. Also n‐HAP/CS/PEG showed higher mechanical strength relative to n‐HAP/CS supportive of bone tissue ingrowths. Copyright © 2014 John Wiley & Sons, Ltd.     

Design and synthesis of novel (Z)-5-((1,3-diphenyl-1H-pyrazol-4-yl)methylene)-3-((1-substituted phenyl-1H-1,2,3-triazol-4-yl)methyl)thiazolidine-2,4-diones: a potential cytotoxic scaffolds and their molecular modeling studies

In an effort to discover potential cytotoxic agents, a series of novel (Z)-5-((1,3-diphenyl-1H-pyrazol-4-yl)methylene)-3-((1-substituted phenyl-1H-1,2,3-triazol-4-yl)methyl)thiazolidine-2,4-dione derivatives (8a–n) were designed and synthesized in various steps with acceptable reaction procedures with quantitative yields and characterized by ¹H NMR, ¹³C NMR, IR, HRMS and ESI–MS spectra. These newly synthesized novel derivatives were screened for their in vitro cell viability/cytotoxic studies against human breast cancer cell line (MCF-7) with various concentrations of 0.625 µM, 1.25 µM, 2.5 µM, 5 µM and 10 µM, respectively. The biological interpretation assay outcome was demonstrated in terms of cell viability percentage reduction and IC₅₀ values against standard reference drug cisplatin. Based on these results, most of the derivatives exhibited promising cytotoxic activity. Among them, particularly compounds 8j (R₁?=?OMe and R₃?=?NO₂) and 8e (R₃?=?CF₃) demonstrate remarkable cytotoxic activity with IC₅₀ values 0.426 µM?±?0.455 and 0.608 µM?±?0.408, which are even better than the standard drug cisplatin 0.636 µM?±?0.458 and compounds 8m (R₂?=?OMe and R₃?=?OMe) and 8c (R₃?=?OMe) exhibited closely equivalent IC₅₀ values to the standard drug with IC₅₀ values 0.95 µM?±?0.32 and 0.976 µM?±?0.313 and rest of the compounds exhibits moderate cytotoxic activity. Moreover, molecular modeling studies and ADME calculations of the novel synthesized derivatives are in adequate consent with the pharmacological screening results.

     

(±)-Camphor-10-sulfonic acid as recyclable and efficient catalyst for the synthesis of some novel coumarin derivatives

A highly competent-diversity oriented synthesis of coumarin core derivatives using a Knoevenagel condensation followed by Michael addition and subsequent cyclization in the presence of (±)-camphor-10-sulfonic acid in a water/ethanol (1:1) solvent system is depicted. Furthermore, easy workup procedures with good yield, rapid reactions with high atom economy, and catalyst recyclability are the fascinating features of the procedure.     

Solid phase extraction of trace metals in water and leafy vegetables using a resin functionalized with potassium 2-benzoylhydrazinecarbodithioate and determination by ICP–AES

A solid phase extraction method for the determination of Cu(II), Mn(II) and Zn(II) metal ions in natural water and leafy vegetable samples by ICP-AES was developed. The method was based on the sorption of metal ions onto Amberlite XAD-16 functionalized with a new chelating ligand potassium 2-benzoylhydrazinecarbodithioate (Amberlite XAD-16-PBHCD) and elution with nitric acid. The optimum experimental conditions for the quantitative sorption of the three metal ions, namely, effect of pH, sample volume, flow rate, concentration of eluent, sorption capacity, kinetics of sorption, and the effect of diverse ions on the sorption of analytes have been investigated. All the metal ions were quantitatively retained by the functionalized resin at pH 5.0 and sorbed metals could be eluted with 2.0?M HNO₃. The detection limits were 5.6, 4.5 and 1.8?µg?L^?1 for Cu(II), Mn(II) and Zn(II), respectively. The developed method was applied for the determination of Cu(II), Mn(II) and Zn(II) in water and leafy vegetable samples.     

Novel [1,2,4]triazolo[3,4-b][1,3,4]thiadiazine derivatives embedded with benzimidazole moiety as potent antioxidants

Fourteen novel [1,2,4]triazolo[3,4-b][1,3,4]thiadiazine derivatives bearing benzimidazole moiety ( 7a-n ) have been synthesized using the one-pot nitro reductive cyclization method. All the synthesized compounds were confirmed by ¹H nuclear magnetic resonance (¹H NMR), ¹³C NMR, fourier-transform infrared (FT-IR), mass spectrum, and elemental analyses. All the title compounds were subjected to in vitro antioxidant activity. The free radical scavenging activity of the compounds was examined using DPPH, nitric oxide, and superoxide radical scavenging methods. The results demonstrated that compound 3-(2-(3,4-dimethoxyphenyl)-1-propyl-1H-benzo[d]imidazol-5-yl)-6-4-tolyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazine ( 7c ) was potent in scavenging both DPPH and nitric oxide radical with IC₅₀ values of 13.57 and 18.55 μg/ml when compared to the standard with IC₅₀ values of 23.75 and 23.14 μg/ml, respectively, which was due to the presence of electron-donating groups. The activity was found to decline when electron-donating groups were replaced by electron-withdrawing groups. Moderate scavenging activity was observed for the superoxide radical. Structure activity relationship and physiochemical properties were studied for all the derivatives.     

Catalytic Transfer Hydrogenation,A Facile Conversion of Hydroxyflavanones Into Hydroxydihydrochalcones

Catalytic transfer hydrogenation of naringenin, hesperetin and eriodictyol using sodium formate as the donor and commercially available pd/C gives the respective hydroxydihydrochalcones in good yields. The method is an excellent alternative to catalytic hydrogenation.