European Journal of Chemistry

Two series of N-phthaloylglycine derivatives were synthesized under Schotten-Baumann conditions. The first series consists of N-phthaloylglycine amides (4a-h), and the second one consists of benzimidazole derivatives of N-phthaloylglycine (6a-d). All the synthesized analogues were evaluated for their in vitro antimicrobial activity by using disc diffusion method. In the first series, compounds 4h (MIC, 0.5 mg/L), 4a (MIC, 0.6 mg/L), and 4e (MIC, 0.7 mg/L) were found to be the most potent against vancomycin-resistant Staphylococcus aureus (VRSA). Furthermore, three compounds i.e. 4g (MIC, 0.8 mg/L), 6b (MIC, 1.5 mg/L), and 4h (MIC, 1.6 mg/L) displayed good activity against methicillin-resistant Staphylococcus aureus (MRSA). All the synthesized compounds exhibited a wide range of antibacterial activity against all of the Staphylococcus aureus resistant strains tested. The structures of the synthesized compounds were characterized by IR, ¹H NMR, ¹³C NMR and MS (EI).

Simple, effective, and high yield synthetic procedure for the synthesis of Schiff bases 5a-c is described. The scope of this reaction was investigated and noted that the presence of nickel(II) nitrate hexahydrate gave the corresponding Schiff bases in excellent yields. The inhibition effects of N-((1-phenyl-3-(thiophen-2-yl)-1H-pyrazol-5-yl)methylene)-4H-1,2,4-triazol-3-amine (PTP), 5c, have been investigated against the corrosion of copper in 0.5 M HCl solution. The investigations were accomplished using potentiodynamic polarization and electrochemical impedance measurements. Potentiodynamic polarization measurements indicated that the examined compound is mixed-type inhibitor. The results of electrochemical impedance indicated that the values of the charge transfer resistance and the inhibition efficiency tend to be increased by increasing the inhibitor concentration.

A novel series of 1,3,5-triazine-chalcone hybrid molecules (4a-ii) have been synthesized and evaluated in vitro for Mycobacterium tuberculosis H37Rv inhibitory potency using Alamar blue assay and the activity expressed as the minimum inhibitory concentration (MIC) in µg/mL. The antitubercular activity screening data revealed that the compound 4z demonstrated comparatively the most potent inhibitory activity, with MIC value 3.125 µg/mL. It is noteworthy that the compounds 4e, 4p and 4bb also showed appreciable inhibitory activity with MIC value 6.25 µg/mL. Most of the compounds displayed significantly promising activity and their structure-activity relationships were also discussed. This could be the remarkable starting point to develop new lead molecules with potential antitubercular activity.

1,3-Dipolar cycloaddition reaction of (2E,2'E)-2,2'-(1,4-phenylene bis(methanylylidene)) bis(3,4-dihydronaphthalen-1(2H)-one) (3) and 2,2'-(1,4-phenylene bis(methanylylidene)) bis(1H-indene-1,3(2H)-dione) (8) with a variety of nitrilimines, generated in situ by triethylamine dehydrohalogenation of the corresponding hydrazonoyl halides, (4) proceeded region-selectively and affording novel spiropyrazoline derivatives 5 and 10, respectively. The mechanisms of the reactions studied are discussed and the structures of the products were confirmed by spectral data and elemental analyses. Also, molecular orbital plots for HOMO and LUMO verify our suggested mechanism and stereo-selectivity of the reaction. The antimicrobial activity of the products was evaluated and promising results were obtained.

Podophyllotoxin belongs to the class of cyclolignan family of natural products, which exhibits strong antimitotic, anti-AIDS (HIV), antitropical skin disease, antimalarial, virucidal, fungicidal and other biological activities. The new tetralone esters (9a-d) of podophyllotoxin analogues were synthesized in good yields by chalcone route to study their structure-activity relationship. All the products obtained were characterized by spectral and elemental analysis data and they were screened for antimicrobial activity. Compounds 9b and 9c were shown significant antibacterial and antifungal activities.

A new series of 2,6-diamino-5-arylazo-4-chloropyrimidine analogues (6-13) were synthesized from the pyrimidine scaffold 5, via diazotization with various amines. Nucleophilic displacement of compound 5 by ethanethiolate or arylthio nucleophiles, afforded the 4-alkylthio analogues (14-16). Treatment of compound 17 or 18 with thiourea under MWI gave the 4-thione derivatives 19 and 20, respectively. On treatment of compound 20 with 2-mercaptoacetic acid furnished the 4-thio analogue (21). Reaction of compound 19 or 20 with sodium hypochlorite followed by ammonium hydroxide afforded the 4-aminothio analogues 22 and 23, respectively. Oxidation of compound 23 with H₂O₂ led to the 4-sulphonamide derivative 24. All new compounds were evaluated for their in vitro antiviral activity against the replication of HIV-1 and HIV-2 in MT-4 cells. Compounds 14-16 and 21 showed an EC₅₀ values of > 2.12, 1.99, 1.80 and 1.92 μg/mL, respectively. In addition, preliminary structure-activity relationship and molecular modeling of compound 15 has been studied.

A few new sulphadimidine incorporating thiophene moiety are synthesized. These compounds were assessed by analytical and spectral data. Antioxidant evaluation for the investigated compounds was evaluated by ABTS assay and bleomycin-dependent DNA-damage; the compounds exhibited weak activities.

From shikimic acid, new series of oseltamivir analogues containing either ether sulfur or ether oxygen at C-3 position were prepared and evaluated for their biological activities. This is the first report on synthesis of oseltamivir analogues with ether sulfur at C-3. Except for compounds 4d, 4f, 7c and 7d, the remaining compounds were found to be active against MCF-7, LU-1 and KB cell lines. As oseltamivir had no cytotoxicity against different cell lines such as MCF-7, LU-1, KB, MDCK, MRC-5, VERO, MK and 293, the modification of alkyl groups at C-3 of the oseltamivir ring framework could significantly increase the cytotoxicity for this class of compounds. Loss of neuraminidase inhibition activity of these synthetic oseltamivir analogues suggested that the alkyl ether groups at C-3 should be critical for their anti-neuraminidase activity.

A complex of Fe(III) with 4-amino-5-(pyridyl)-4H-1,2,4-triazole-3-thiol was prepared and evaluated as a photodegradation for rigid poly(vinyl chloride) (PVC). Polyvinyl chloride dissolved with Fe(III) complex in THF solvent to form PVC films of 5% (40 μm) thickness containing different concentrations (0.01, 0.02, 0.03, 0.04 and 0.05 g) of the complex by weight. These different samples were produced by the casting method from the solvent. The photodegradation of films was investigated using UV-visible spectra. The photostabilization activity of these compounds was determined by calculating the photodecomposition rate constant (K_d) for modified PVC films against a blank.

A series of 2-hydroxypyrrolidine/piperidine derivatives (4a-h)/(4i-m) were prepared by reacting 2,3-dihydrofuran (2a)/3,4-dihydro-2H-pyran (2b) with various heterocyclic amines (3a-h), using FeCl₃.6H₂O as catalyst. The synthesized compounds were characterized by various physic chemical techniques such as elemental analysis and spectral analysis viz, ¹H NMR, ¹³C NMR and Mass.

Flexible nanostructured and conducting metal-polymer films have been found promising applications in pharmaceuticals and flexible electronics. These could be used as anti-bacterial agent, bio-warfare treatment, or as sensors for environmental monitoring and protection. However, mechanical strength and metal-polymer adhesion are crucial issues for practical applications of such films. Another issue associated with synthesis of such polymers is the necessity of a simple, convenient and cost-effective method. This work focused on the above issues and reports the synthesis of nanostructured Ag-polymer films (brown, blue and golden colored) and conductive Au-Ag-polymer film with a good combination of flexibility, mechanical strength and metal-polymer adhesion. The films were synthesized by simple and cost-effective routes. Ag-polymer films were prepared by one-step method through studying the effect of metal concentration and curing process. Conductive film was obtained by gold plating on the selected Ag-polymer film. SEM and EDS clearly indicated the existence of metal particles on the metal-polymer films.

New N-substituted-2-methyl quinazolin-4(3H)-ones derivatives comprising 1,3,4-thiadiazole, Schiff bases and 2-azetidinone moieties are reported. The structures of the newly prepared compounds were confirmed by FT-IR and ¹H NMR spectra. The compounds were also evaluated for their antimicrobial, antioxidant and study of inhibition on some enzymes activities. The results suggest that the compounds possess broad spectrum of in-vitro antimicrobial activity. Antioxidant results obtained into the present study indicate that compound 5 show moderate better scavenging activity. Compound 5 demonstrated inhibitory effects on GOT, GPT, GGT and ALP activities, and these effects increase with increasing the concentration of the compound.

Two thioether diamines 2-(2-aminoethylthio)aniline and 2-(3-aminopropylthio)aniline have been prepared employing a new procedure by reaction of 2-aminothiophenol and N-(2-bromoethyl)phthalimide or N-(3-bromopropyl)phthalimide, respectively. Then two new potentially pentadentate (N₂O₂S) Schiff base ligands derived from direct condensation between two maintained diamines and 2-hydroxybenzaldehyde or 5-bromo-2-hydroxy benzaldehyde were synthesized. Also, Zn(II) and Cd(II) complexes of Schiff base ligands have been prepared. These compounds have been characterized by physico-chemical and spectroscopic methods.

The 6-methyl-3, 4-diphenyl-7-(2-phenylhydrazono) pyrimido [1', 2':1, 5] pyrazolo [3,4-c] pyridazin-8(7H)-one and 3,4-diphenyl-7-(phenyldiazenyl)pyrimido[1',2':1,5]pyrazolo[3,4-c]pyridazine-6,8-diamine derivatives were applied to polyester fiber as disperse dyes. They were found to exhibit varying in hue from orange-yellow to orange-red, their absorption spectral characteristics, fastness properties and colour assessment are also reported.

Condensation of cyanoacetamide 3 with cycloalkanones and elemental sulfur in the presence of morpholine yielded the bisthiophenes 4 and 5. Also, its (3) condensation with terphthalaldehyde or coupling with p-phenylenedidiazonium chloride afforded compound 13 and 14, respectively. Furthermore, cyanoacetylation of compound 4 or 5 afforded the cyanoacetamides 6 and 7, respectively. Knoevenagel condensation of compound 7 with aromatic aldehyde afforded the arylidenes 10, 11 and coumarin 12, respectively. Treatment of compound 3 with CS₂ in DMF/KOH followed by alkylation reaction with ethyl bromoacetate afforded the triester derivative 16, which gave 3-aminothiophene 17 upon heating in DMF/TEA. Moreover, refluxing of compound 23 with α-haloketones afforded 3-aminothiophenes 24 and 25. Identity of newly synthesized compounds was established by the spectral data and novel compounds were evaluated as antioxidant agents.

The most widely practiced reaction of diazonium salts is azo coupling. In this process, the diazonium compound is attacked by an electron-rich substrate. When the coupling partners are arenes (phenols), the process is an example of electrophilic aromatic substitution. Poly (vinyl chloride) (PVC) react with 4-[(5-mercapto-1,3,4-thiadiazol-2-yl)diazenyl]phenol (L) in THF to form the PVC-L compound, which have been characterized by spectroscopic methods. PVC-L has further been reacted with different metals ions to form PVC-L-M^II complexes. The structure of these complexes has been characterized by FT-IR and UV-Vis spectrophotometry. The optical properties in the region from 200-900 nm were also studied using UV-Vis spectrophotometer. The optical data analyzed and interpreted in term of the theory of phonon assisted direct electronic transitions according to energy gap data the conductivity of PVC and the complexes.

The propose of this article is to evaluate the effect of caffeine on some indicators of bone metabolism in rats by biochemical measurement of minerals, bone densitometry and histometry. Forty eight Wistar albino male rats, age 6-8 weeks and weighing 100±0.11 g were randomly divided into four groups (12 rats each). Each group of animals received balanced diet; the second, third and fourth groups received pure caffeine dissolved in distilled water with different oral doses (0.35, 0.43 and 50 mg/day) for 12 constitutive weeks. Blood samples were withdrawn at 3, 6, 9 and 12 weeks. Serum and urinary calcium, phosphorus, magnesium and caffeine were estimated. Bone density and bone length were measured. Bone minerals were also estimated. The data revealed that the bone density was significantly decreased (p ≤ 0.05) in the fourth set (1.05±0.10 g/cm³) for right femur rats. The length of right femur increased with more doses of caffeine and it was highly significant in the fourth group (3.40±0.12cm). The proportion of each calcium, phosphors and magnesium in bone ash was significantly lower (p ≤ 0.05). Serum levels of calcium, phosphors and magnesium were decreased with increasing the dose over time. The levels of urinary calcium and magnesium were increased significantly (p ≤ 0.05) in group 4, but phosphors was raised (p ≤ 0.05) in all groups. In conclusion, intakes of caffeine in amounts >300 mg/dl significantly affected the quantitative composition of the bone and this finding lead to be at a greater risk for bone loss. These results suggested that appropriate lifestyle changes to conserve bone mineral density (BMD) by reducing the consumption of caffeine and need further studies to elucidate the mechanism that caffeine effects on bone metabolism.

A selective, sensitive, and rapid liquid chromatography-electro spray ionization tandem mass spectrometry method has been developed and subsequently validated for the simultaneous determination of Moexipril (MOX), and its active metabolite Moexiprilat (MOXT) in spiked human plasma, using Benazepril (BENZ) as an internal standard (IS). Various modes were tried and the Multiple Reaction Monitoring (MRM) mode was found the most suitable one. The two analytes and Benazepril (IS) were extracted from human plasma by simple protein precipitation using acetonitrile as the precipitating solvent. The stationary phase used was a C18 Sunfire column while water and acetonitrile at 0.1% formic acid (30:70, v:v) was used as a mobile phase. The flow rate used was 0.8 mL/min. Food and Drug Administration guidelines were followed for the method validation. The linearity range was found to be 0.5-100 ng/mL for MOX and 5-200 ng/mL for MOXT and the correlation coefficient was more than 0.9980 for each analyte. Results for accuracy and precision showed satisfactory results. Also the method was compared with reported HPLC method and no significant difference was found.

β-Cyclodextrin catalyzed synthesis of indole derivatives from indole, aldehyde and N-methylaniline is reported. The β-cyclodextrin can be recovered and reused without significant loss of catalytic activity, and it is inexpensive, readily available when compared to other cyclodextrins (α, γ).

A simple, green and environmentally benign procedure has been developed for the synthesis of 2,3-dihydroquinazoline-4(1H)-ones in basic ionic liquid via the cyclocondensation of 2-amino benzamide with an aldehyde. This offers several advantages such as high yields, simple procedure, low cost, short reaction times, mild and solvent free condition.

An efficient and convenient route is described for the synthesis of new pyrazolo [1,5-a] pyrimidine derivatives by the reaction of 4-(4’-chloro-phenylazo)-5-amino pyrazole with α,β-unsaturated carbonyl compounds (chalcones) using polyethylene glycol (PEG-400) as benign reaction medium. The advantage of this protocol includes the excellent yields, operational simplicity, short reaction times and avoidance of volatile organic solvents and expensive catalysts.

This review deals with synthesis, reactions and their applications of pyrano triazolo pyrimidines. The main purpose of this review is present a survey of literatures on the reactivity of amino imino derivatives and carboxylic acid derivatives. Some of these reactions have been applied successfully to the synthesis of biological important compounds.

Erratum to ‘‘Photostability studies on gemifloxacin and lomefloxacin in bulk powder and dosage forms” [Eur. J. Chem. 5 (1) (2014) 73-80].