Mini-Reviews in Organic Chemistry - Volume 20, Issue 4, 2023

Oxadiazole is a five-membered aromatic heterocyclic ring having two nitrogen and one oxygen atom. Various isomeric forms have been reported for oxadiazole, such as 1,3,4-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, etc. Currently, a considerable population worldwide is facing several mental problems due to a competitive lifestyle. The present status of available medicines do not promise complete cure without any adverse effects. Therefore, these disorders are continuously challenging the researchers to come up with new molecules with superior efficacy and minimum side effects. All the isomeric forms of oxadiazole have numerous potential in treating various mental problems such as Parkinsonism, Alzheimer’s, schizophrenia, and epileptic disorders. In this review article, we summarize several recently reported synthetic strategies for preparing different oxadiazole and its derivatives which were found effective in psychological disorders. The researchers will be able to obtain the necessary information (synthesis strategies) through this article for their future research on new molecules containing the oxadiazole moiety. Furthermore, this review article will help the researchers in the fight against mental disorders and highlights possible molecules for the treatment of mentally challenged people.

Simple heterocyclic moieties are quite famous in synthetic organic chemistry due to their bioavailability, ease of laboratory synthesis, and variety of applications in multidisciplinary fields. Benzimidazole is an N-containing benzo-fused chemical compound with the formula C7H6N2 and belongs to the family of heterocyclic aromatic organic compounds. It is a potent bioactive molecule with prominent therapeutic activities and has been found to have prior importance in medicinal chemistry. Several advanced investigations also proved benzimidazole and its derivatives have significant antimicrobial, antiparasitic, antifungal, and anti-carcinogenic activities. It has also gained popularity in material science as well. Because of its versatile applications, numerous research groups paid considerable attention to synthesizing benzimidazoles. o-Phenylenediamine (OPD) is considered the traditional substrate for benzimidazole synthesis. This review discussed the synthetic approaches of benzimidazoles from OPD as a primary reactant with diverse substrates like aldehydes, alcohols, carboxylic acids/ esters, etc. We have also briefed up reactions using primary substrates such as o-nitroanilines and o-dinitrobenzenes. This review report covers research findings published since 2016 and describes numerous practical and greener synthesis methods. It also narrates innovative biocatalysts, photocatalysts, and nanocatalysts, which are used for the synthesis of benzimidazoles.

2-pyridones represents ubiquitous scaffolds often present in both natural products and pharmaceutical compounds. Due to their wide applications in medicinal chemistry, it is not surprising that the synthesis of 2-pyridone derivatives has attracted organic chemists for many years. This mini review focuses on the recent development in the multi-component synthesis of 2-pyridones for the period 2011 to 2021, particularly those that involve the three/four component reactions of activated methylene, aldehyde or ketone withdifferent intermediate materials under different conditions.

p-Tosylmethyl isocyanide (TosMIC) and its derivatives represent an important class of polyfunctional reagents, making them privileged “building blocks” in the targeted organic synthesis to design a plethora of heterocycles as well as natural products. This review summarizes and highlights the synthetic potential of p-tosylmethyl isocyanide and its derivatives in the reaction with various aldehydes to afford valuable heterocycles. The catalytic and technological innovations discussed in the review reveal the ease of reaction. Moreover, their mechanistic schemes are also displayed.

The review summarizes information regarding the industrial use of 3- and 4-amino-1,2,4- triazoles, the basic raw material for the industry of fine organic synthesis. A description of the existing production methods for the synthesis of 3- and 4-amino-1,2,4-triazoles under laboratory conditions is provided. Three main areas of use of these amines and their derivatives have been identified: Agriculture, medicine, high-energy substances and gas-generating composition. It has been shown that one of the earliest areas of widespread use of 3- and 4-amino-1,2,4-triazoles is the production of plant protection products. The mass production of various insecticides, fungicides, plant growth regulators, retardants, and nitrification inhibitors of nitrogen fertilizers has been organized. The use of these amines in medicine consists of the production of known drugs, such as furazonal, thiotriazoline and cardiotril, which have hepatoprotective, antioxidant, and anti-ischemic activity. The industrial processing of 3- and 4-amino-1,2,4-triazoles into explosives, solid propellants and gas-generating compositions is a third well-known field of application. The high reactivity of amines and the variety of areas for their use are explained. A significant emphasis is given to the analysis of aminotriazoles. This is the production of new types of salts and electrically conductive ionic liquids, corrosion inhibitors of non-ferrous metals, and catalysts for curing epoxy resins. The results of recent studies are discussed, and the prospects for using 3- and 4-amino-1,2,4-triazoles as raw materials for the production of new reagents in analytical chemistry, proton-exchange membranes, and new condensed nitrogen-containing heterocycles are explained.

Efficient translation of CO2 into value-added compounds is a fascinating topic in green chemistry. The effective conversion of CO2 into useful chemicals and materials helps civilization flourish in the long run. Carbon dioxide has shown tremendous applications by replacing dangerous chemicals like phosgene, isocyanates, or carbon monoxide, resulting in more environment-friendly operations. This article is an overview in which we highlight current advances in synthesizing quinazolinone, a favoured scaffold in the pharmaceutical industry for its therapeutic value in the treatment of various pathologies. The complementarity of succinct methods aids the ability to generate libraries of functionalized quinazolinone derivatives.

Functionalized polysubstituted quinoxalines have been widely reported to possess appealing biological activities of great pharmaceutical importance, which drew researchers into exploring promising synthetic protocols. On top of that, prospects on green chemistry are driving research paradigms into more cost-effective, facile, environmental-friendly, sustainable, and scalable approaches. This paper reviews the green synthesis methods of quinoxaline derivatives using recyclable heterogeneous catalysts, green solvents and energy-mediated methods that have been extensively studied and published since 2010 to offer an insight into the ongoing greener trend in the scientific field.