European Journal of Chemistry

Green, red and far-red emitting Borondipyrromethene (BODIPY) derivatives with 3-ethynylthiophene units at various positions around the BODIPY core were synthesized and their photophysical properties were studied. 3-Ethynylthiophene substitution at the 2,6 positions caused significant increase in Stokes shift while substitution at the 8 and 4,4’ positions had no effect. Photooxidation of 1,3-diphenylisobenzofuran (DPBF) in the presence of 3-ethynylthiophene substituted BODIPY derivatives confirmed singlet oxygen generation. 3-Ethynylthiophene substitution at the 2,6 positions is more effective in singlet oxygen generation compared to 4’4 substitutions. Substitution through phenyl group at the meso (8) position gave the lowest rate for singlet oxygen production. All 3-ethynylthiophene containing BODIPY derivatives were highly photo-stable under our experimental conditions.

The hydrazone ligand obtained from 2-thiophene carboxaldehyde and nicotinic hydrazide reacts with equimolar mixture of vanadyl acetyl acetonate in methanol to yield oxovanadium(IV) complex with 2-thiophenecarba nicotinic hydrazone. The prepared compound shows effective solubility in organic solvents such as acetonitrile, DMF and DMSO. Molar conductivity data of the complex revealed its non-electrolytic behavior in DMF and DMSO. EPR spectra of 2-thiophenecarba nicotinic hydrazonato oxovanadium(IV) was recorded in DMF at LNT and g and A values were calculated. The complex was proposed to be square pyramidal in geometry. Cyclic voltammogram of the complex in DMF was studied by changing the scan rates 50, 100, and 200 mV/sec. ΔE values of the complex showed the reversible criterion and ipc/ipa values which were close to 1 indicating that the redox couple as reversible. Thermogram of the complex was recorded to find the weight loss at different temperature ranges. Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectra showed mass number of the molecular ions.

Amino acid of tryptophan (Trp) was chosen as a drug. A systematic approach was made to study its interaction with some transition metal ions, and qualitatively and quantitatively examine the thermodynamic and kinetic phenomena on this model drug. To accomplish these tasks, the stability constants of Trp complexes with Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Pb(II) at temperatures of 25, 30, 35, and 40 °C were determined potentiometrically, utilizing modified Bjerrum’s method. Potentiometric titrations were carried out in water, and water:dioxane mixture (50:50, v:v). Our findings showed that the stability constants of the complexes increased as the dioxane content was raised or temperature was elevated. The negative values of ΔG° are indication of spontaneity of the processes. ΔH° values are positive, conveying the complex formation is an endothermic process and ΔS° values are positive contributing more to spontaneity, causing reaction favoring and disordering. The variations of natural logarithm of the stability constants versus 1/T are linear leading to evaluation of the stability constant of the complexes at any temperature. Moreover, kinetic study gave rise to estimation of rate constant and activation energy for each complex formation process. It was concluded that the order of increasing stability of the complexes is: k_{f Co(II)-Trp} » k_{f Zn(II)-Trp} < k_{f Pb(II)-Trp} < k_{f Ni(II)-Trp} < k_{f Cu(II)-Trp} < k_{f Fe (III)}- _Trp. Furthermore the activation energy values for the aforementioned complexes in water-dioxane mixture obeyed the following trend E_{a Zn(II)-trp} < E_{a Fe(III)-Trp} < E_{a Ni(II)-trp} < E_{a Co(II)-trp} <E_{a Cu(II)-trp} <E_{a Pb(II)-trp}.

This study aimed at the development of simple and cheap conductometric method that can be used for the determination of naproxen in bulk and dosage forms. During the study, naproxen was titrated with sodium hydroxide (Method A) and potassium hydroxide (Method B) and the end points were determined with conductivity cell. Variables affecting the end point determination were also studied in the range of 1-10 mg/mL of naproxen. The proposed methods were validated by precision and recovery studies. The percentage recoveries ranged from 99.15±0.659 and 101.13±0.543 with % RSD of 0.897 and 0.749 with sodium hydroxide and potassium hydroxide, respectively. The methods were effectively applied for the determination of naproxen in tablet dosage form. The methods proposed in this study can be used as substitute for more composite and classy methods used for the determination of naproxen and are highly reproducible as compared to other reported methods.

The antioxidant activity of new hydrazones derived from bisdemethoxycurcumin pyrazole was investigated. The study was divided into two main parts: The first one includes the synthesis and characterization of the target compounds from bisdemethoxycurcumin (BDMC), while the second step is devoted to the investigation of their antioxidant activities. In the first step of synthesis, the curcumin-pyrazole (2) was synthesized by the reaction of BDMC with hydrazine hydrate. Later, the obtained product treated with ethyl 2-chloroacetate to produce curcumine ester (3), then the product was converted to hydrazide (4) by the reaction of curcumin ester (3) with hydrazine hydrate. Finally, curcumine hydrazones (5a-f) were synthesized from the reaction of hydrazide (4) with substituted aromatic aldehydes. All compounds were characterized with the aid of suitable spectroscopic techniques. The antioxidant activity of the prepared compounds was studied against the stable radical α,α-diphenyl-β-picrylhydrazyl. The study showed that only the phenolic OH-containing compounds (2, 5b and 5f) have antioxidant activity.

Two new compounds, 1H-indole-7-amine (1) and N-(1H-indol-7-yl)-2-methylbenzamide (2) were synthesized and structurally characterized by NMR and FT-IR spectroscopic techniques. The molecular structure of compound 2 was further elucidated by single-crystal X-ray diffraction technique. Moreover, the crystal packing of compound 2 is analyzed in terms of non-covalent N-H···O, C-H···π, and parallel displaced π···π interactions. Hirshfeld surface analysis and decomposed fingerprint plots of the compound 2 were performed to visualize the presence of strong hydrogen bond N-H···O and C-H···π stacking interactions. Hirshfeld surface analysis and decomposed fingerprint plots show that the structure of compound 2 is stabilized by H···H, N-H···O, C-H···π and π···π intermolecular interactions and these interactions contribute mostly to molecular self-assembly in the crystal. In addition, compound 2 was evaluated for both their in-vitro antibacterial and antifungal activity. The obtained results have been reported, explained and compared with fluconazole and ampicillin used as reference drugs.

A one pot three component reaction of 4-phenyldiazenyl-1-naphthol (1), p-chloro benzaldehyde (2) and malononitrile or ethyl cyanoacetate (3) in ethanol/piperidine under reflux afforded 2-amino-4-(p-chlorophenyl)-6-phenyldiazenyl-4H-naphtho[1,2-b]pyrano-3-carbonitrile (4a) and ethyl 2-amino-4-(p-chlorophenyl)-6-phenyldiazenyl-4H-naphtho[1,2-b]pyrano -3-carboxylate (4b). Structure of these compounds was established on the basis of IR, ¹H NMR, ¹³C NMR, Mass and UV-Vis spectra. Molecular geometry of compounds 4a and b was obtained at B3LYP/6-31+G(d) level. Two tautomers and two conformers were geometrically optimized. The tautomers are separated by about 7.942 kcal/mol while rotational conformers are only separated by 0.511 kcal/mol. Molecular reactivity descriptors including global electrophilicity, hardness, softness and local condensed Fukui functions were computed and discussed. Frontier molecular orbitals (HOMO and LUMO) were also computed.

Two ligands; pyrrolidine-1-carbodithioate sodium (L¹) and piperidine-1-carbodithioate sodium salt(L²) and their nickel(II) mixed ligands complexes with 1,10-phenanthroline (L³) have been synthesized and characterized by FT-IR, UV-visible,¹H NMR spectra. The biological activities of these complexes were also evaluated. The spectral data indicated that the 1,10-phenanthrolineand dithiocarbamate ligands are considered as a bidentate nitrogen and sulfur ligands, respectively. The study suggested that the above ligands formed complexes of general formula [Ni(L^x)₂(L³)₁] and [Ni(L^x)₁(L³)₂]Cl (x=1 or 2) mononuclear (monomer) complexes. The complexes show moderate and selective activity against tested microorganisms.

In this study, we developed and validated different spectrophotometric and chromatographic methods for determination of clotrimazole (CLO) and hydrocortisone (HDC) in their combined dosage form. The developed spectrophotometric methods were first derivative spectrophotometry (¹D) by measuring the peak amplitude at 247.4 and 236.2 nm for CLO and HDC, respectively, second derivative of ratio spectra (²DD) at 225.4 nm for CLO and 269 nm for HDC, dual wavelength spectrophotometry (DW) by measuring absorbance difference between 225.4 and 264 nm for CLO and between 228 and 247 nm for HDC determination, advanced absorbance subtraction method (AAS) between 225.4 and 264 nm and mean centering of ratio spectra (MCR) spectrophotometric method in the range of 232-265 nm. On the other hand, the proposed chromatographic method was Ultra Performance Liquid Chromatography method (UPLC) using acetonitrile:water (50:50, v:v) as a mobile phase and the peaks were detected at 228 nm. All these methods were successfully applied to determine the two studied drugs in pure forms; laboratory prepared mixtures and combined dosage form. Methods validations were carried out regarding linearity, accuracy, precision and selectivity. The spectrophotometric methods exhibited a linear dynamic range over 5-40 and 5-45 µg/mL for CLO and HDC, respectively, and over 3-35 and 5-50 µg/mL for UPLC method. Sensitive and selective spectrophotometric and UPLC methods for the determination of clotrimazole and hydrocortisone in their topical formulation were successfully developed and validated. The developed methods were statistically confirmed to be accurate, precise and reproducible.

A rapid and sensitive method for determination of cystatin C (CC) protein in human blood by means of high performance liquid chromatography (HPLC) was developed and validated. Estimated glomerular filtration rate (eGFR) has been calculated for the patients with chronic kidney disease (CKD). Ion pair liquid chromatography technique was utilized to separate CC along with UV detection. Calibration curve with excellent correlation (r² = 0.99) over the range from 0.75 to 20.50 mg/L of CC was accomplished. Limits of detection and quantify-cation were 0.375 and 0.75 mg/L of CC, respectively. The recoveries were in the range of 93.6-102.3%. Intra-assay and inter-assay variabilities were 8.2 and 6.14%, respectively.

A series of new molecules having 4-substituted-3,4-dihydro-2H-benzo[b][1,4]oxazin-2-yl)methane substituted sulfonamide derivatives were synthesized. The structures of the synthesized compounds were elucidated and confirmed by ¹H NMR, ¹³C NMR, Mass spectra, and the purity was checked through HPLC analysis. The compounds were also evaluated for their in vitro antiproliferative activity against MCF-7, HeLa, A-549 and DU-145 cancer cell lines by MTT assay. Compounds 4d, 7c and 7d were tested for their activity against a panel of eight human kinase at 10 µM concentrations. Among them the compounds 4d and 7d showed very promising activity against CDK5/P25 kinase with 66 and 70% inhibitions, respectively. Compound 7c also showed promising activity of 59% inhibition. The preliminary bioassay showed that most of the compounds were antiproliferative with different degrees, and some compounds showed better activity than 5-fluorouracil which was used as positive control.

A facile synthesis of new phthalimide dithiocarbamate and dithioate analogs 8a-j, 9a-e and 9g-j were achieved by the reaction of N-chloromethyl and N-bromoethylphthalimide with carbon disulfide (CS₂) and various amines. The structures of the synthesized analogs were elucidated by spectroscopic methods, including IR, ¹H NMR and ¹³C NMR, and ESI-HRMS techniques. The antiproliferative activity of the newly synthesized compounds was also evaluated against various human cancer cell lines. The compound 9e and 9i exhibited the highest activity against human breast adenocarcinoma MCF-7 and hepatocellular carcinoma HepG2 cells. Compound 8f showed better antiproliferative effect against colon carcinoma HCT-116 and cervical carcinoma HeLa compared to thalidomide. The binding affinity to vascular endothelial growth factor receptor (VEGFR) of some compounds was assessed in addition to molecular docking study. Compounds 9e and 9i showed high docking score values and they significantly declined the concentration of VEGFR.

A series of new molecules having 3-(substituted)-4,5,6,7-tetrahydro-6-(substituted)-1H-pyrazolo[3,4-c]pyridine and 3-(substituted)-5,6-dihydro-6-(substituted)-1H-pyrazolo[3,4-c] pyridin-7(4H)-one derivatives were designed and synthesized in large scale (grams range). The structures of the synthesized compounds were elucidated and confirmed by ¹H NMR, ¹³C NMR, Mass spectra; and purity was also checked through LC/MS and HPLC analysis. The antiproliferative activity of the compounds was checked for lung cancer, cervical cancer, breast cancer and prostate cancer on panel of four cell lines. A few compounds (13c, 13g, 15g and 15h) showed promising antiproliferative activity in the range of 5.12-17.12 µM which were further tested for their inhibitory activity against panel of 8 human kinases at 10 µM concentrations. The compounds 13c, 13g, 15g and 15h shows prominent inhibitory activity against Aurora-A, Aurora-B, CDK₅/P₂₅ and mTOR kinases.

The compound N-(dibenzylcarbamothioyl)-3-methylbutanamide as a thiourea derivative was synthesized and structurally characterized by NMR and FT-IR spectroscopic techniques. The molecular structure of compound was also characterized by single crystal X-ray diffraction method. Crystal data for title compound C₂₀H₂₄N₂OS: monoclinic, space group C2/c (no. 15), a = 19.6882(9) Å, b = 9.4045(4) Å, c = 19.5012(8) Å, β = 98.433(2)°, V = 3571.8(3) Å³, Z = 8, μ(CuKα) = 1.665 mm^-1, 25057 reflections measured (9.168° ≤ 2Θ ≤ 144.196°), 3500 unique (R_int = 0.0322, R_sigma = 0.0200) which were used in all calculations. The final R₁ was 0.0363 (I>2σ(I)) and wR₂ was 0.0910 (all data). Intermolecular contacts obtained from X-ray single crystal diffraction study were also explored using both Hirshfeld surfaces and fingerprint plots. Hirshfeld surface analysis showed the occurrence of S···H, O···H and H···H contacts that display an important role to crystal packing stabilization of the thiourea derivative compound. In addition, the compound was evaluated for both their in-vitro antibacterial and antifungal activity.

5-(4-Methoxy-3-methylphenyl)-2(3H)-furanone was prepared and reacted with some nucleophilic and electrophilic reagents. The condensation of furanone with aromatic aldehydes or phthalic anhydride yielded the corresponding 3-arylidenefuranone derivatives and phthalide, respectively. While the treatment of furanone with amines in refluxing ethanol led to the formation of amides. The reaction of the amides with thionyl chloride afforded the corresponding isothiazolones. The benzimidazole derivative was prepared via the reaction of the 2(3H)-furanone with o-phenylenediamine in boiling ethanol. However, hydrazine hydrate affected ring opening of furanone to give the corresponding acid hydrazide, which underwent in situ cyclization into the corresponding pyridazinone. The base catalyzed ethanolysis of furanone afforded the corresponding ethyl ester.

Two new quinolone derivatives, 5-nitroquinolin-8-yl-3-bromobenzoate (1) and 5-nitroquinolin-8-yl-3-chlorobenzoate (2), were synthesized and their structures were elucidated using X-ray diffraction techniques. Both compounds crystallized in P2₁/n (monoclinic) space group having four independent molecules in asymmetric unit. The dihedral angle between benzene and planner quinoline rings in compounds 1 and 2 were found to be 117.7(2) and 117.4(2)ᵒ, respectively. No intermolecular hydrogen bonding was observed in compound 1. However, C-H···O intermolecular interaction was found to connect the molecules in crystal lattice of compound 2. Hirshfeld surfaces analysis was performed to evaluate the directions, and strength of interactions of molecules of compounds and 1 and 2 with neighbouring molecules, and the major contribution in the crystal packing was due to O-H (1, 24.6% and 2, 25.1%) interactions. The synthesized quinoline derivatives were found as potent anti-bacterial agents against E. coli reference (ATCC25922 and ATCC 35218) and multi-drug resistant strains (M2 and M3) with 91.42 to 94.72% inhibition. Both compounds 1 and 2 showed weak antileishmanial activity against L. Major promastigotes in vitro with IC₅₀ values 73.2±3.1 and 72.2±2.3 mg/mL, respectively, and also found as cytotoxic in nature against 3T3 fibroblast cell line.

Quality by Design (QbD) for the pharmaceutical industry includes the design, development and production control of products and production processes from the beginning to the end of the product development phase for ensuring the consistent quality of a pharmaceutical product. The QbD is a systematic scientific approach aimed at meeting the needs of the patient in the desired and targeted quality and aiming to produce the same quality pharmaceutical product in this direction. Process Analytical Technology, which is assessed in that regard, is part of a design quality approach that is used to design, analyze, and control real-time measurements of quality and performance criteria for raw and processed materials to achieve the desired final product. This scientific and systematic approach to pharmaceutical product development, which is also acknowledged and supported by the health authorities, serves to the changing and developing pharmaceutical sector.