Mini-Reviews in Organic Chemistry - Volume 19, Issue 7, 2022

Piperazine is a six-membered heterocyclic ring with two nitrogen atoms at positions one and four. This piperazine moiety can be present in a slew of well-known medicines that have pharmacophoric effects on a variety of receptors. Various piperazine analogs have core biological activities involving the activation of monoamine pathways, primarily on neurotransmitter receptors. As a result, piperazine analogs have a wide range of central clinical uses, including anxiolytic, antipsychotic, and antidepressant. Due to its stimulant and euphoric effects, benzyl-piperazine is the prototype of piperazine analogs, and this molecule is the main substance of recreational drugs. This review focuses on the activity of piperazine pharmacophore on diverse neurotransmitter receptors used therapeutically as anxiolytics (buspirone), antidepressants (vortioxetine), antipsychotics (clozapine), and other drugs.

Thermal reactions accompanied by emission of light (UV-Vis, IR, radio waves) are briefly reviewed. The Boltzmann law requires that molecules (atoms, ions, radicals, radical-ions) have distribution of energy levels according to the exponential law. Criteria for observation of emission of light quanta are presented. The well-known example is chemiluminescence, where a thermally “hot” molecular product returns to the ground state emitting light. Other types of similar reactions are presented. The observation of microwave emission is discussed.

Covalent Organic Frameworks (COFs) are porous crystalline materials that have emerged as promising molecular materials in optoelectronics, catalysis, and gas storage applications. COFs exhibit unique features, such as adaptability for various substrates, high chemical stability, tunability, ease of working, and recyclability, making them efficient catalysts. The current mini-review article discusses the synthesis and applications of COFs as catalysts. We hope that the present review will be highly beneficial for researchers working in the area of COFs and their applications in catalysis.

Nowadays, heterocyclic compounds have attained a prominent place among the various classes of aromatic organic compounds. Benzimidazoles are important classes of heterocyclic compounds that comprise six-member benzene and five-member imidazole fused ring systems. Benzimidazole scaffolds remain the central focus among the available heterocyclic compounds because of several pharmacological, clinical, and biological properties. Benzimidazoles attain the focus due to their stability, outstanding bioavailability, and wide spectrum of biological efficiency. The present study reveals and discusses the chemistry of various benzimidazole scaffolds widely used in medicinal chemistry with the available data until 2021.

Marine microorganisms are an important source of active natural products and drugs, which have become a research hotspot in recent decades. Due to the special marine ecological environment, the metabolic pathways of marine organisms have certain characteristics, and their metabolites are novel in structures and unique in activities. Xanthones and benzophenones are widely distributed in nature, and most of them are found in fungi and higher plants. They are described as "dominant structures" in the field of modern medicine because of their obvious pharmacological activities, including antibacterial and antifungal activities. This paper reviews the research progress of isolated microbial xanthone and benzophenone compounds from marine sources at home and abroad in recent years, including their chemical synthesis and biosynthesis, which lays a foundation for future utilization and development.