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.

Pyrimidine compounds continue to attract great interest in the field of organic synthesis due to
their various chemical and biological applications observed, especially in recent times. As a
result, this review covering some periods from 1957 to 2021 has been prepared to discuss some
of the structural pathways of these compounds as well as some of their interactions and
applications.

Thiazolopyrimidnes are considered one of the most interesting classes in heterocyclic chemistry
due to their pharmaceutical importance. Herein, we report the synthesis of some new heterocyclic
compounds containing thiazolopyrimidine starting from compound (1) which was previously
prepared in literature. The starting compound was allowed to react with different alkylating
agents such as chloroacetone, chloroacetyl chloride, and phenacyl bromide to afford derivatives
(2-4). Compound (5), benzylidene derivative, was obtained by the reaction of compound (2) with
benzaldehyde while amino-dicarbonitrile compound (6) can be obtained by the reaction of
compound (5) and malononitrile. Acetylation of amino group in compound (6) with chloroacetyl
chloride led to formation of compound (7). Nucleophilic substitution of chlorine in compound
(7) by aniline gave compound (8) which further subjected the Munich reaction to form compound
(9). All new synthesized compounds were characterized using different elemental and spectral
analysis.

Starting from 3-cyano-4,6-distyrylpyridin-2(1H)-thione (1), the compound N-(4-
chlorophenyl)-2-((3-cyano-4,6-distyrylpyridin-2-yl)thio)acetamide (2) was prepared.
Compound (2) underwent cyclization upon heating in ethanolic sodium ethoxide solution to
give the corresponding cyclized form 3-amino-N-(4-chlorophenyl)-4,6-distyrylthieno[2,3-
b]pyridine-2-carboxamide (3). The elemental analyses and spectroscopic data of compounds
(2) and (3) are in agreement with their proposed structures. Their insecticidal activity against
cowpea aphid, Aphis craccivora Koch, was studied. The results of insecticidal activity for
compounds (2) and (3) against the nymphs and the adults of the tested insects exhibited that
compounds (2) and (3) have a higher insecticidal activity than that of acetamiprid, a reference
insecticide, after 24 h of treatment.

Heterocyclic compounds with effective solid-state luminescence
offer a wide range of uses. It has been observed that combining
pyrimidine and indole moieties in a single molecule can enhance material
behavior dramatically. Here, different heterocyclic compounds with
indole and pyrimidine moieties have been synthesized effectively, and
their structures have been validated using NMR, IR, and mass
spectroscopy. The photoluminescence behavior of two substances was
investigated in powder form and solutions of varying concentrations.
After aggregation, one molecule displayed a redshifted luminescence
spectrum, whereas another homolog showed a blueshift. Thus, density
functional theory calculations were carried out to establish that
introducing a terminal group allows modifying of the luminescence
behavior by altering the molecular packing. Because of the non-planarity,
intermolecular interactions, and tiny intermolecular distances within the
dimers, the materials demonstrated a good emission quantum yield (Φem) in the solid state (ex. 25.6%). At high temperatures, the
compounds also demonstrated a stable emission characteristic.