This study reports the development of a new series of pyrazolo[4,3-b] pyridine and pyrazolo[1,5-a] pyrimidine derivatives designed as potential antischistosomal agents. A diverse set of fused nitrogen-containing heterocycles was successfully obtained and subjected to preliminary biological relevance assessment based on their structural features. These newly synthesized frameworks, belonging to scaffolds previously associated with notable antimicrobial and antiparasitic properties, demonstrate promising potential for further evaluation against Schistosoma species. The findings highlight the value of these heterocyclic systems as candidates for developing alternative therapies to complement existing schistosomiasis treatment strategies

Keywords: Pyrazolopyridines; Pyrazolopyrimidines; Heterocyclic synthesis; Condensation reactions

(E)-2-(naphthalen-1-yldiazenyl) malononitrile (NDMN) was synthesized via a diazotization–coupling reaction and evaluated for its antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli. The compound showed strong, concentration-dependent antibacterial activity, with significantly higher efficacy against MRSA than E. coli, as confirmed by disc diffusion, MIC, and MBC assays. These results suggest that NDMN is a promising synthetic antimicrobial agent, particularly against Gram-positive resistant bacteria, and merits further biological and toxicity investigations.

The rise of multidrug-resistant (MDR) bacteria poses a significant challenge to the antibacterial efficacy of the

produced chemical, (2-(2-(2-nitrophenyl) diazinyl) malononitrile), which is generated from malononitrile and a

diazo moiety. The molecule was synthesized using the diazotization of 2-nitroaniline, followed by coupling with

malononitrile, resulting in NPDAM with an 85% yield and a melting point of 123-125 °C. The substance at

concentrations of 1, 5, and 10 mg/mL was assessed against methicillin-resistant Staphylococcus aureus (MRSA)

(SA121) and Escherichia coli (EC49). The chemical exhibited efficacy against MRSA at varying doses, yielding

clear zones of 29.6, 32.6, and 33.0 mm, in contrast to E. coli at the same concentrations, which produced clear

zones of 10, 11.6, and 14.6 mm, respectively. The microdilution technique was employed to ascertain the

minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. The compound

exhibited low minimum inhibitory concentration (MIC) values against MRSA at concentrations of 1 and 5 mg/mL

(19.5 and 4.89 μg/mL, respectively), in contrast to E. coli, which demonstrated inhibition at 39.0 and 9.78 μg/mL

at the same concentrations. Additionally, it yielded the lowest MIC values (0.97 μg/mL) against both bacteria at

a concentration of 10 mg/mL. The MBC values against MRSA ranged from 39.0 to 1.95 μg/mL, while against

E. coli, the MBC values were slightly lower, ranging from 78.1 to 1.95 μg/mL. In conclusion, all chemical

concentrations exhibited activity against the studied microorganisms, indicating their potential as antimicrobial

agents.

Keywords: Malononitrile, Diazo compounds, antimicrobial activity, MRSA, E. coli.

Small molecule, (2-(2-(2-nitrophenyl)diazenyl)malononitrile) (NPDAM), is synthesized and its chemical structure is characterized by different analyses. NPDAM powder is identified as polycrystalline monoclinic structure, whereas the thermally deposited films have nanostructure character with average particle size of 39 nm. NPDAM films are utilized for manufacturing hybrid solar cells in the structure of Au/NPDAM/p-Si/Al. The dark current-voltage (I-V) curves of the diode are measured in the temperature range 303-383 K and the thermionic emission theory is employed to extract the ideality factor, n, and potential barrier height, ∅ at forward applied voltages of V≤0.20 volt. The n value increases, whereas the ∅ value decreases with decreasing temperature. This behavior is analyzed in terms of the lateral inhomogeneous barrier following Gaussian distribution at the NPDAM/p-Si interface. Cheung and Cheung functions are used for extracting the values of series resistance, Rs, n and ∅. The behavior of these parameters as a function of temperature is discussed. At forward applied voltages 0.20<V≤2, the I-V relation reveals crossover from thermionic emission to square power law. This behavior is discussed by means of the space charge limited current. Under illumination, the device exhibits a response to light exposure with a photoelectrical conversion efficiency of 2.91 %.

Two pyrazolo[4,3-b] pyridine derivatives namely; 2,3-dihydro-6-(4-methoxyphenyl)-1-methyl-3-oxo-2-phenyl-1H-pyrazolo[4,3-b]pyridine-5-carbonitrile (L1) and 2,3-dihydro-6-(4-hydroxyphenyl)-1-methyl-3-oxo-2-phenyl-1H-pyrazolo[4,3-b]pyridine-5-carbonitrile (L2) were prepared. The thermal analysis showed that the L1 is stable up to 266 °C, whereas L2 is stable up to 376 °C. The L1 and L2 powders were found to have polycrystalline structure in which their lattice parameters and Miller indices were determined. Thin films of L1 and L2 were deposited by thermal evaporation technique. The absorption spectra of the films were measured, from which the optical band gap of L1 and L2 films was estimated as 2.72 and 2.83 eV, respectively. Two devices based on the films of both materials, independently, were deposited onto p-Si single crystal substrates, were fabricated and showed rectification behavior. The current

In this paper, of primary interest is to synthesis 8-(1H-indol-3-ylazo)-naphthalene-2-sulfonic acid (INSA) and to evaluate the main parameters of Au/INSA/n-Si/Al diode in dark and under illumination. Different techniques are used for interpreting the proposed INSA chemical structure. The dark current-voltage measurements were achieved in the temperature range of 293−413 K. It is noticed that INSA films modify the interfacial barrier height of classical Au/n-Si junction. At low applied voltages, the I–V relation shows exponential behavior. The values ideality factor, n, and the barrier height, φ, are improved by heating. The abnormal trend of n and φ is discussed, and a homogenous barrier height of 1.45 eV is evaluated. The series resistance is also calculated using Norde's function and it changes inversely with temperature. The space charge limited current ruled with exponential trap distribution dominates at relatively high potentials, trap concentration and carriers mobility are extracted. The reverse current of the diode has illumination intensity dependence with a good photosensitivity indicating that the device is promising for photodiode applications.

Several new pyrazolo[3,4-b]pyridines 7a,b were prepared via reacting compound 1,5-dimethyl-4-nitroso-2-phenyl-1H-pyrazol-3(2H)-one 1 with the arylmethylenemalononitriles 3 .The reaction of 4-(aryldiazenyl)-1H-pyrazole-3,5-diamines 2 with arylmethylenemalononitriles 3a,b ,ethoxymethylenemalononitrile 3d and 2-(1H-benzo[d]imidazol-2-yl) -3-(dimethylamino)acrylonitrile 12 resulted in the formation of pyrazolo [1,5-a]pyrimidine derivatives 8,10 and 15 respectivily.

الوصف

In this study, 6-(5-bromothiohen-2-yl)-2,3-dihydro-1-methyl-3-oxo-2-phenyl-1H-pyrazolo[4,3-b]pyridine-5-carbonitrile (BDPC) powder was synthesized. BDPC powder showed a polycrystalline structure, whereas the thermally evaporated films had an amorphous structure. The optical parameters such as absorption coefficient and refractive index were calculated in the spectral range 200–500 nm. Spectral distribution analysis of the absorption coefficient revealed that the films had an indirect band transitions with energy gaps of 2.57 eV and 3.5 eV. According to the single oscillator model, the oscillation energy, dispersion energy, and dielectric constant were estimated. The room-temperature current–voltage characteristics of the fabricated Au/BDPC/p-Si/Al heterojunction showed diode-like behavior. The ideality factor, the barrier height and series resistance were determined based on thermionic emission theory and

A novel organic compound containing antipyrine and thiadiazole moieties, N-(5-{[antipyrinyl-hydrazono]-cyanomethyl}-[1,3,4]thiadiazol-2-yl)-benzamide (ACTB) has been synthesized. The thermal properties, alternating current electrical conductivity (σAC) and electrical modulus of ACTB have been reported. The thermal properties were analyzed using differential scanning calorimetry and thermogravimetric measurements. The AC measurements of bulk ACTB were performed in frequency range 100 Hz–5 MHz and temperature range 303–503 K. The frequency dependence of AC conductivity is found to follow Jonscher’s universal power law with the applicability of the correlated barrier hopping model. The temperature dependence of σAC could be described in terms of Arrhenius relation with two activation energies. The activation energy decreases with increasing frequency. The dielectric relaxation behavior is explained in terms of electric modulus formalism. At relatively higher temperatures, the imaginary modulus spectra exhibit asymmetric maxima with peak-width much broader than that of the Debye peak and are skewed toward the high frequency sides of the maxima with increasing temperature. The relaxation time is calculated and exhibited thermally activated process with activation energy of 0.77 eV.

The electrical and dielectric properties of the synthesized 2-(antipyrin-4-ylhydrazono)-2-(4-nitrophenyl)acetonitrile (AHNA) have been studied. The direct and alternating current (DC and AC) conductivities and complex dielectric constant were investigated in temperature range 303–403 K. The AC conductivity and dielectric properties of AHNA were investigated over frequency range 100 Hz–5 MHz. From DC and AC measurements, electrical conduction is found to be a thermally activated process. The frequency-dependent AC conductivity obeys Jonscher's universal power law in which the frequency exponent decreases with increasing temperature. The correlated barrier hopping (CBH) is the predominant model for describing the charge carrier transport in which the electrical parameters are evaluated. The activation energy is found to decrease with increasing frequency. The behaviors of dielectric and dielectric loss are discussed in terms of a polarization mechanism. The dielectric loss shows frequency power law from which the maximum barrier height is determined as 0.19 eV in terms of the Guintini model.