Current Organic Chemistry - Volume 26, Issue 18, 2022

This article aims to draw the attention of the scientific community toward the use of calcium-based reagents in various organic transformations. These complexes are capable of activation and nucleophilic addition of olefins, carbonyls, nitro groups of catalysts, epoxides, methyl aromatics and alcohols. These complexes are capable of activating different functional groups for nucleophilic addition to alkene, carbonyl, nitro, epoxide, methylarene and alcohol groups. Calcium-based catalysts have broad tolerance to substrates, reaction pathways, and appear to be sustainable alternatives to transition metals, rare earth metals, for a variety of organic transformations. The scope of this review is limited to catalytic alterations mediated by calcium complexes. This is the first broad review article that covers all aspects of calciummediated reactions up to the year 2022.

Hedychium coronarium J. Koenig belongs to the family Zingiberaceae, generally known as butterfly ginger, butterfly lily, cinnamon jasmine, garland flower and ginger lily. It is a medicinal plant grown throughout India, Southeast Asian countries, China, Japan, and Brazil. Traditionally, it is used as a febrifuge, tonic, anti-rheumatic, used to treat asthma, headache, arthritis, bronchitis, blood diseases, eye diseases, gastric diseases, and many other diseases. H. coronarium contains important secondary metabolites such as alcohols, aldehydes, ketones, esters, oxides, phenolics, flavonoids, saponins, glycosides, labdane diterpenes, and sesquiterpenes. Limonene, myrcene, p-cymene, camphene, γ-terpinene, β-pinene, 1,8-cineole, linalool, α-pinene, and 10-epi-γ-eudesmol have been identified as the main constituents of volatile oils of H. coronarium along with the key elements like trans-meta-mentha-2, 8-diene, linalool, α-terpineol, terpin-4-ol, α-pinene, γ-terpinene, and camphene. Phytochemical studies on various solvent extracts of H. coronarium revealed that the plant holds the diterpenes- coronarin-A-I, isocoronarin-D, pacovatin A; sesquiterpene- (+)-nerolidol, hedychiol A, hedychiol B 8,9-diacetate; sterols- daucosterol, stigmasterol, β-sitosterol and flavonoid- 5-hydroxy-3,7,4’-trimethoxyflavon, chrysin. Coronarin D, a bioactive compound, has been reported for anti-cancer activities of H. coronarium. Diterpenes isolated from H. coronarium extracts and essential have been reported as antioxidant, antitumor, antidiabetic, antiproliferative, antihelmintic, mosquitocidal, larvicidal, antilithiatic, chemopreventive, antiophidian, insecticide, antifungal, allelopathic, and antimicrobial agent. Based on the literature, the essential oils, extracts and isolated active compounds of H. coronarium could be used to develop as flavor and fragrance agents, food preservatives, botanical pesticide, neutraceuticals and pharmaceuticals. This review paper aims to go over traditional uses, phytochemical analysis, pharmacological activities, scientific techniques for variety development, conservation, and proper utilization and identify future opportunities for H. coronarium.

Triazole, which can exist in two isomeric forms: 1,2,3- and 1,2,4-triazole, is considered to be a privileged scaffold with recognized biological and pharmaceutical potential. Furthermore, due to their physicochemical properties, the applications of triazoles have been explored in fields ranging from medicinal chemistry to materials science. Triazoles have not only drawn the attention of the scientific community for all the aforementioned properties but also due to their ability to be incorporated into other bioactive and functional molecules. The connection between two pharmacophores makes it possible to potentiate specific biological activities or add different properties. Interest in the compatibility of the triazole nucleus with peptide structures is highlighted in the development of new therapeutic targets. In epigenetics, triazole is linked to various compounds that are used in the creation of new drugs that could potentially inhibit histone-modifying enzymes. Other new and potentially more effective materials that can take advantage of a triazole moiety include light-emitting diodes and solar cells, among others. Hence, we propose a novel approach to the promising applications of triazolic ring, a compound that has been gaining prominence in organic chemistry due to its applicability to many different fields.

Plant parasitic nematodes are destructive endoparasites having deleterious effect on about 5000 agricultural crops notably vegetables, fruits, field crops, ornamental plants, and even human health. The immense damage caused by nematodes has been estimated as US $150 billion per annum (21.3%) despite of the availability of commercialized nematicides. Nevertheless, crop protection is still dependent on the development of novel chemicals due to development of pesticide resistance line by diverse pathogens. The utilization of heterocyclic moieties in agricultural industry is considered as an effectual practice to manage plant diseases either as systemic or non-systemic. These scaffolds consist of heteroatoms in their ring structure such as N, S, O, which give a boost to their biological activity as reported. The principal heterocyclic scaffolds are the benzimidazole, pyridine, nicotinic acid, pyrrole, indole, isatin, triazine, triazole, pyrazole, amides, imidazole, cinnamic acid, oxadiazole, coumarin, thiadiazole, etc. derivatives which owing to their marvelous structural diversity are widely exploited. The prime purpose of the review is to provide information to researchers around the globe about varied heterocyclic scaffold decorations that have been employed for the synthesis of potential nematicidal candidates from 2000 onwards and their utilization to combat complex destructive biotic stress. Therefore, this review assembled the considerable synthetic chemistry and nematicidal investigation of moieties against various plant parasitic pathogens along with structure-activity relationship studies. The scientific details provided in the article will highlight the importance of heterocyclic compounds in the agricultural industry and may pave a pathway for the development of novel nematicides.

In medicinal chemistry, benzyloxy-benzaldehyde is a valuable intermediate, to which the attachment of a five membered heterocycle may be advantageous from the point of view of drug design. The starting iodo-benzyloxy-benzaldehydes were synthesized by the Obenzylation of o-, m- and p-hydroxybenzaldehydes with 2-, 3- and 4-iodobenzylbromides in refluxing acetone or acetonitrile in the presence of potassium carbonate and potassium iodide. Starting from the corresponding iodo-benzyloxy-benzaldehydes, the Suzuki-Miyaura carboncarbon cross-coupling reaction was utilized to get five membered heteroaryl-substituted benzyloxy- benzaldehydes. Various methods for Suzuki cross-coupling were studied. The applied boronic acids were 2- and 3-thiophene-boronic acids, as well as 2- and 3-furan-boronic acids. The reactions were followed by TLC and HPLC-UV-MS analysis. The products were purified by column chromatography. The original Suzuki method comprising NaOEt/EtOH, tetrakis(triphenylphosphine) palladium, in toluene was applied only in a few cases, resulting in poor yields. In several cases, the Suzuki coupling of substituted aryl iodides with 2-furanboronic acid failed to result in the formation of the expected products using the palladium acetate/tri(o-tolyl)phosphine/aqueous tripotassium phosphate/dimethoxyethan system. But reacting 3-thiophene-boronic acids with the corresponding iodo-benzyloxybenzaldehydes, this method afforded the products in 76-99% yields. The more powerful tetrakis(triphenylphosphine)palladium/aqueous cesium carbonate/ dimethylformamide system seemed to be more successful in cases of 2-thiophene boronic acid as well as 2- and 3-furan-boronic acids, providing the desired products in 75-93% yield. Twenty-six new compounds were synthesized.