The toxicity of a novel series of ten pyranothiazolopyrimidine derivatives (1–9a,b) against the insect Aphis gossypii (Glover, 1887) has been determined. In addition, the safety profile of two selected compounds 2,8 against earthworms was determined. Acetamiprid insecticide was utilized as a reference insecticide. Spectroscopic data and elemental analyses were used for verifying the structures of the synthesized compounds. Studying the toxicity of synthesized derivatives against the Aphis gossypii (Glover, 1887) revealed that compounds 2,8 were more active than the reference insecticide acetamiprid against Aphis gossypii (Glover, 1887), while the remaining compounds exhibited moderate to low activities. But, in detecting the safety profile against earthworms (Aporrectodea caliginosa) for compounds 2,8, it was found that; compound 2 (LC50 = 32.7753–22.4079) and compound 8 (LC50 = 131.6081–101.0537) are less toxic and safer on earthworms than acetamiprid (LC50 = 0.1992–0.0086) after 5 and 10 days of test. Also, the chemical characteristics of the investigated soil holding the used earthworms diversified significantly before and after treatment with agrochemicals.

The structural and optical properties, as well as dielectric characteristics at various frequencies (0.1 Hz—20 MHz) and temperatures, T (300–400 K), of hydrothermally synthesized SnO₂ nanoparticles, Cu/SnO₂, and Fe/SnO₂ composites have been investigated. The crystal structure is mostly formed of a tetragonal SnO₂ phase, with a second phase of monoclinic CuO or rhombohedral Fe₂O₃ detected in Cu/SnO₂, and Fe/SnO₂ composites, respectively. The direct optical band gap, residual dielectric constant, and density of charge carriers are increased, while ac conductivity (σ_ac) and dielectric constant decreased in Cu/SnO₂ and Fe/SnO₂. The value of σ_ac was decreased while the electric Q-factor was increased by increasing T. SnO₂ obeyed the hole-conduction mechanism for 400 ≥ T (K) ≥ 300, while Cu/SnO₂ and Fe/SnO₂ obeyed the electronic-conduction mechanism for 400 ≥ T (K) > 300. The binding energy is independent of T for SnO₂, whereas it increases with rising T for Cu/SnO₂ and Fe/SnO₂ composites. F-factor and electronic polarizability are improved by a rise of T for SnO₂ and Cu/SnO₂ meanwhile are decreased for Fe/SnO₂. The electrical impedance of the grains and their boundaries as well as equivalent capacitance are increased by increasing T and have higher values for Fe/SnO₂ at T > 300 K. The obtained results recommend the synthesized Cu/SnO₂ and Fe/SnO₂ composites to be used as catalysts for water purification, anodes for lithium batteries, supercapacitors, and solar cell applications amongst others.

The structural parameters, optical properties, and dielectric constants at a frequency (f) range of 0.1–20 MHz, and temperature (T) range of 300–400 K of hydrothermally synthesized M/SnO₂ nanocomposites (for simplicity M denotes oxides of Al, Ni, or Mn) were compared. Rietveld refined X-ray powder diffraction (XRD) analysis demonstrated the formation of hexagonal, cubic, or spinel crystal structures of Al₂O₃, NiO, or Mn₃O₄ phases, respectively, besides the tetragonal rutile crystal structure of SnO₂. The impact of Al addition on the optical band gap of SnO₂ is negligible while it decreased or increased by incorporation of Ni or Mn, respectively. The residual lattice dielectric constant of SnO₂ was increased, while the real part of the dielectric constant and the ac conductivity of SnO₂ were decreased by M incorporation. The dielectric parameters are remarkably affected by selected M, T, and f values and their changes agree with the Maxwell-Wagner model. The Q-factor of SnO₂ was increased by M addition while decreased with increasing T. The Ni/SnO₂ obeys the hole conduction at T ≤ 330 K, while Mn/SnO₂ and Ni/SnO₂ obey the electronic conduction at T > 330 K. The binding energy is independent of the chosen T for SnO₂, whereas it sharply increases for Ni/SnO₂ and slightly decreases for Al/SnO₂ and Mn/SnO₂. The F-factor of SnO₂ was slightly decreased by M addition, but it was increased with T for SnO₂, Al/SnO₂, and Mn/SnO₂ while was decreased for Ni/SnO₂. The Cole-Cole plots for M/SnO₂ composites were analyzed, and the components of the equivalent circuit were determined. The electrical impedance, resistance of grains, resistance of grain boundaries, and equivalent resistance of SnO₂ were increased by M incorporation, whereas equivalent capacitance was decreased. The findings recommend the SnO₂-based nanocomposites for applications in optoelectronics, lithium batteries, supercapacitors, and solar cell devices.

The reaction of 7-methyl-1-(morpholin-4-yl)-3-sulfanylidene-2,3,5,6,7,8-hexahydro-2,7-naph thyridine-
4-carbonitrile with hydrazine hydrate gave 1-hydrazinyl-7-methyl-3-sulfanylidene-2,3,5,6,7,8-hexahydro-
2,7-naphthyridine-4-carbonitrile which was used as a key intermediate for the synthesis of new fused naphthyridine-
based heterocyclic systems. The condensation of 1-amino-7-methyl-5-(morpholin-4-yl)-6,7,8,9-
tetra hydrothieno[2,3-c][2,7]naphthyridine-2-carbonitrile with different reagents afforded fused tetra- and
pentacyclic systems. The structure of the newly synthesized compounds was confirmed by elemental analysis
and spectral techniques.

In examining for unique insecticidal agents, two derivatives namely, 2-((3-cyano-4,6-
distyrylpyridin-2-yl)thio)-N-(4-nitrophenyl)acetamide (2) and 3-amino-N-(4-nitrophenyl)-4,6-
distyrylthieno[2,3-b]pyridine-2-carboxamide (3) were synthesized from distyrylpyridine-2-
thione (1). The new compounds were structurally clarified by spectral and elemental analysis
data. The insecticidal activity of these compounds were carried out against cowpea aphid, Aphis
craccivora Koch. It is demonstrated that the compounds 2 and 3 have noteworthy insecticidal
activity against nymphs of cowpea aphid with LC50 values of 0.025-0.027 ppm and 0.005-0.006
ppm after 24 h and 48 h of treatment, respectively. Also, the compounds 2 and 3 have noteworthy
insecticidal activity against adults of cowpea aphid with LC50 values of 0.112-0.129 ppm and
0.014-0.015 ppm after 24 h and 48 h of treatment, respectively, that were comparable to that of
the control acetamiprid.

Oxygen-containing heterocycles are largely distributed in natural and synthetic compounds.
Coumarins are among the most famous heterocycles which possess one oxygen atom in their
rings. Coumarins are classified as multifunctional scaffold and are used as anti-oxidant reagents,
anti-inflammatory, anti-microbial, anti-fungal, anti-HIV active, analgesic, anti-histaminic,
insecticides, dyes, herbicides, sensitizers, perfumes, cosmetics and food additives. Due to their
diverse applications in industrial and pharmaceutical fields, many chemists have given
significant interest to these compounds. Herein, the review highlights various methods for the
synthesis and interactions of coumarin moiety as one of the most efficient categories of
heterocycles.