Introduction: The synthesis of bisindolylalkanes has been carried out for more than two decades using several catalysts. Method: In the present study, naturally available orange juice has been demonstrated to be an efficient green catalyst for the synthesis of bisindolylalkanes from the reaction of indoles with different carbonyl compounds. Result: In this one-step process, the products were obtained with excellent yield and in a short reaction time. Conclusion: This reaction-catalysed by orange juice is a new, inexpensive, and environmentfriendly synthetic procedure for the preparation of bisindolylalkanes.

Background: B-lactams have been primarily utilized as a leading class of effective anti-biotics. They have been found to show activity against various diseases, prompting the scientific community to prioritise innovative protocols for their synthesis. The general and well-known syn-thetic strategy involves the classical Staudinger reaction exhibiting [2+2] cycloaddition reaction. However, the protocol utilizes stoichiometric excess of base for efficient product formation. Objective: A smarter and more acceptable approach for the synthesis of B-lactams would be to reduce the excess base to a catalytic amount, furnishing a catalytic version of the Staudinger reac-tion. The modified version can eliminate the hazards arising out of excess use of the base, ultimately promoting the environmentally benign approach. Methods: With this hypothesis, a base-catalyzed approach in dimethyl formamide (DMF) towards the synthesis of B-lactam via Staudinger reaction has been endorsed under moderate reaction conditions. Results: The scope of the substrates was explored with both electron-withdrawing and electron-releasing substitutions in the formation of B-lactam. The reduction of the base amount from stoichiometric to catalytic amount was justified by the involvement of DMF in generating the basic condition for the reaction. Conclusion: It was hypothesized that the decomposition of DMF under the base-catalysed reaction condition can generate dimethylamine, which produces the required basic environment.

Introduction: This research article describes the production, quantification, and purification of belinostat from 3-nitrobenzaldehyde as the starting material. A cascade-step process produces higher yields when compared to all previous existing methodologies. Method: The procedure involved the following: Horner–Wadsworth–Emmons (HWE) reaction of aromatic aldehydes with triethylphosphonoacetate in the presence of potassium carbonate, reduction of the nitro group to the amino group, sulfochlorination by thionyl chloride, aniline-mediated sulfonamidation, and hydroxylamine amidation as the last step. Results: The prepared solid belinostat was purified, and an acceptable yield of 56-60% was obtained. Conclusion: The approach has several key benefits, including low-cost beginning materials, straightforward techniques, safer and more reliable results, and substantial environmental advantages.

Background: In recent years, the use of nanomaterials as heterogeneous catalysts has attracted much attention in organic reactions. Methods: A magnetically separable mixed metal oxide, Manganese Zinc Iron Oxide (Mn2O3/Fe3O4/ZnO) nanoparticles as nanocatalyst (Mmo@NCt) were synthesized using ultrasonic wave methods in the presence of polyethylene glycol as surfactant. In the second part of the present study, a practical procedure for the one-pot ternary condensation of aromatic aldehydes, β-naphthol, and urea in short reaction time for the synthesis of pharmaceutically interesting naphtho[1,2- e][1,3]oxazine derivatives using Mmo@NCt as an efficient, cost-effective and recyclable nanocatalyst under green conditions has been developed. Results: The analysis of phase purity, magnetic structure, size, and morphology of the as-synthesized nanocatalyst was characterized by X-ray diffraction, VSM, SEM, and EDX techniques. The results of SEM imaging showed that all compounds have a spherical morphological structure with a mean diameter of 16.50 ± 3.94 nm. The structure of the products was confirmed by FT-IR, 1HNMR spectroscopy, and melting point. Conclusion: This project was designed and performed with the use of magnetic nanocatalysts as a suitable method with high efficiency a shorter time for the synthesis of naphthoxazinones heterocyclic compounds due to the medicinal importance of water as a green solvent.

: Nanoparticles have emerged as highly promising catalysts due to their unique physical and chemical properties arising from their small size and high surface area–to–volume ratio. This review delves into the diverse applications of nanoparticles as catalysts in various chemical reactions. A key advantage lies in their substantial surface area–to–volume ratio, facilitation, enhanced accessibility of reactants, and heightened interaction with the catalyst surface. This distinctive characteristic results in improved catalytic activity and efficiency. Additionally, size-dependent properties, such as surface plasmon resonance and quantum confinement effects, offer opportunities for tailoring catalytic behavior. Despite their immense potential, challenges such as synthesis, stability, toxicity, aggregation, and recyclability require attention. Future research should prioritize scalable and sustainable synthesis methods, improve catalyst stability under harsh conditions, and ensure safe handling and disposal. This review provides an overview of the role of nanoparticles as catalysts and highlights their significance in various fields, highlighting their exceptional performance, versatility, and environmental benefits.

Abstract: Over the past decade, heterocyclic compounds and their derivatives have emerged as promising substances with potential pharmacological applications due to their interesting biological properties. The significance of heterocyclic compounds in drug discovery and development is evident from the fact that a majority of drugs in the pharmaceutical market incorporate heterocyclic compounds as active substances or ingredients. Various synthetic methods and advancements have been devised to prepare these heterocyclic compounds using diverse catalysts under mild conditions. Layered double hydroxides (LDHs)-based materials have gained considerable attention across different fields, and their usability can be significantly enhanced via the selection of metal cations, their molar ratios, surface complexation, and intercalation modifications. The synthesis and application of LDH-based materials as catalysts have garnered increasing interest due to their exceptional properties. Moreover, LDH-based materials have found extensive use as heterogeneous catalysts in the synthesis of numerous heterocyclic compounds. This review presents the latest developments in the catalytic application of LDH-based materials as solid heterogeneous catalysts in the synthesis of heterocyclic compounds, covering literature published from 2018 to 2023.

Background::Benzimidazole is a remarkable heterocyclic chemical compound in which the phenyl ring is fused with the imidazole ring at positions 4 and 5. Benzimidazole derivatives have lots of medicinal activity in the pharmaceutical industry. Therefore, the synthesis of benzimidazole derivatives is challenging in this scientific field.Methods::In benzimidazole synthesis, simple nucleophilic substitution and condensation reactions involving carbonyl compounds and o-phenylenediamine have been used in previous times. Currently, green chemistry aspects such as solvent-free conditions, metal-free conditions, or using nanoparticle catalysts in various ways involving condensation, and cyclization are the methods of the new era.Results::Green chemistry methods are used widely in various chemical reactions, such as it was observed that the use of solvent-free conditions, metal-free conditions, or using nanoparticle catalysts molecules is a more efficient way to synthesize benzimidazole derivative.Conclusion::In this review, benzimidazole scaffold syntheses that have only recently been described in the literature through the end of 2021 are covered. Monosubstituted benzimidazoles (MSBs) and disubstituted-benzimidazoles (DSBs) are the primary targets of our research currently. Different ways have been found to make functionalized derivatives of benzimidazole, which are shown in this review as a powerful scaffold.

Background: In the search for a new and effective synthetic approach to bio-logically chromene-derived compounds, a series of 2-amino-7, 7-dimethyl-5-oxo-4H-tetrahydrochromene-3-carbonitrile derivatives (4a-i) were synthesized. This synthesis involved the use of 4-(dimethylamino)pyridiniump-toluenesulfonate (DPTS) as a catalyst in an aqueous medium. Additionally, the relative stability between isomers was investigated using DFT/B3LYP calculations. Methods: The target compounds were synthesized through a multicomponent reaction of 5,5-dimethyl-1,3-cyclohexanedione (dimedone) 1, various arylaldehydes (2a-i), and malononitrile 3 in water and were recrystallized in ethanol. The reaction was promoted using DPTS, which is a low-toxic, inexpensive, commercially available, and easy-to-handle catalyst. Results: The catalytic activity of DPTS was investigated in a condensation reaction conducted in an aqueous medium at room temperature. All synthesized compounds displayed considerable antimicrobial activities against human pathogenic bacteria and fungi. Conclusion: The developed synthetic protocol demonstrates energy efficiency, shorter reaction time, environmental friendliness, high product yields with purity, and scalability to gram-scale synthesis. DPTS proved to be a valuable contribution to the field of organocatalysis. The synthesized compounds were screened for in vitro antimicrobial activities, demonstrating varying potency against the microbial strains. Compound 4h exhibited the most potent activity with a zone of inhibition (ZOI) measuring 15 mm against E.coli. This was followed by compounds 4b, 4d, 4f, and 4g, which displayed a ZOI of 12 mm. Furthermore, the antifungal results revealed promising anticandidal activity for compounds 4b, 4e, and 4h, with a lower minimum inhibitory concentration (MIC) of 0.031 mg/ml. In addition, molecular electrostatic potential (MEP) mapping, reactivity indices such as electronegativity, electrophilic index, softness, and hardness, as well as frontier molecular orbitals (HOMO-LUMO), were used to provide further evidence regarding the stability and reactivity of the synthesized products.

Background: Ketone is one of the important functional groups in synthetic chemistry. For this reason, organic chemists focused on the synthesis of ketone starting from various functionalities since nineties. One of the method deals with the conversion of carboxylic acids to ketones in a one pot manner. We have recently reported a one pot transformation of carboxylic acid to ketone using TsCl or MsCl as an activator of carboxylc acid. In our previous reports, two equivalents of organometallic reagent have been used which may not be useful in medicinal chemistry. In this report, we have developed an alternative process for the transformation where only one equivalent of organometallic reagent has been employed. Objective: In present scenario, we are interested to develop a process for the transformation of carboxylic acid to ketone using one equivalent of an organometallic reagent. Methods: A carboxylic acid reacted with tosyl chloride in the presence of a sodium hydride to form a mixed anhydride. Here, the acidic proton was removed from the reaction mixture as hydrogen gas. This mixed anhydride was then treated with one equivalent of an organomagnesium reagent at -30°C to obtain the desired ketone. Results: Following the optimum conditions, a few commercially available carboxylic acids were treated with TsCl, followed by the treatment of phenyl magnesium and methyl magnesium bromide to obtain phenyl and methyl ketones, respectively, in good to excellent yields. Conclusion: A simple and modified one pot method for the conversion of carboxylic acids to ketone has been reported. In this developed process, one equivalent of the organomagnesium reagent has been used to obtain the desired ketone under the optimized reaction conditions.

Aims: The aim of this study is to investigate the p-toluene sulphonic acid (p-Ts.OH)- catalyzed reaction of racemic-azetidine-2,3-diones with enantiomerically pure cis and trans-4- hydroxy-L-proline in refluxing ethanol culminating in a synthesis of substituted novel 3-(pyrrol-1- yl)-azetidin-2-ones at the C-3 position. Methods: This work describes an alternative synthetic route enabling the tandem transformation of proline to pyrrole, followed by intramolecular chirality transfer to the β -lactams ring. Results: All four diastereomers of 3-(pyrrol-1-yl)-azetidin-2-ones could be achieved in good to excellent yield with high diastereoselectivity in a single-pot operation. Conclusion: This method can be applied to other activated carbonyl compounds and functionalized pyrroles can be obtained through an expeditious process.