Mini-Reviews in Organic Chemistry - Volume 20, Issue 1, 2023

5-Arylidene-2,4-thiazolidinedione (5-A-TZD) is an emerging precursor molecule in medicinal chemistry for discovering multifunctional therapeutic agents. For synthesizing this precursor molecule, Knoevenagel Condensation (KC) is one of the most excellent tools in modern organic chemistry. The 5-A-TZD framework has a variety of therapeutic functions such as antidiabetic, anticancer, antimicrobial, and anti-inflammatory. As a result, several approaches and methods of KC have been established for the synthesis of this multifunctional precursor. However, the use of highly corrosive catalysts, prolonged reaction times, by-products formation, and poor product yields are the main drawbacks in 5-A-TZDs synthesis via KC. Therefore, several authors have been successfully established fast, effective, and environmentally sustainable protocols of KC using organic catalysts, inorganic catalysts, heterogeneous solid catalysts, ionic liquids (ILs), and bio-catalysts to synthesize 5-A-TZD derivatives with high conversion yield and selectivity. In this review, we have summarized the recent approaches for synthesizing 5-A-TZDs via KC and their therapeutic application as a precursor molecule in medicinal chemistry.

Ionic liquid-promoted one-pot synthetic methodologies have emerged as a frontier for the facile access of diverse heterocycles. Owing to the high adaptability of ionic liquids (ILs), the design of functionalized ILs with desired specific and attuned properties, ideally satisfying the one-pot syntheses, are of great importance and endeavor. In particular, with the addressed drawbacks related to the use of ionic liquids as a homogeneous catalyst, the concept of using ionic liquid supported magnetic nanoparticles has drawn much attention as viable alternatives. This review focuses on the potential of functionalized ionic liquid immobilized magnetic Fe3O4 nanoparticles for the domino synthesis of diverse heterocyclic systems.

Heterocyclic compounds have specific structural peculiarities, imparting immense applications in various fields. This study has explored the medicinal importance of a captive heterocyclic compound, 1H-Indole-2,3dione, commonly known as isatin. The flexibility in the structure of isatin makes it more innovative to have applications in the biological and analytical fields. In this minireview, we have discussed Schiff bases of isatin having activities, such as antidiabetic, antioxidant, antidiabetic, antimalarial, antiviral, anticonvulsant, anti-inflammatory and analgesic activity, and also the importance of this compound in various fields based on the reports mainly focussed on the current and past couple of years.

Carbon Nanotubes (CNTs) possess a unique one-dimensional molecular geometry with a large surface area. Recently, CNTs have become a thrust area of research as they play a crucial role in molecular engineering due to their excellent mechanical, electrical, and thermal properties. CNTs have a wide range of applications in various fields due to their unique properties. The Multiple Walled Carbon Nanotubes (MWCNTs) are thermally, mechanically, and structurally stronger than single-walled carbon nanotubes (SWCNTs). The sublimation of carbon in an inert atmosphere is the basis of synthetic methods of CNTs like the solar method, laser ablation, and electric arc discharge. Specific chemical methods like CVD, electrolysis, catalytic decomposition of hydrocarbons, heat treatment of a polymer, ball milling, etc., can also be used to prepare CNTs. Attempts have been made in the present review to discuss all synthetic methods of CNTs, their discoverers, the importance of techniques, various parameters that affect the process in detail, and the mechanism for the growth of CNTs. This article aims to provide a comprehensive pathway for researchers who deal with the synthetic methodology of carbon nanotubes. This review is also interesting for readers of material science and nanochemistry.

Background: Vilsmeier-Haack formylation of N-arylacetamides and used them as a key intermediate for preparation of 2-(piperidin-1-yl) and/ or 2-(morpholin-1-yl) quinoline-3- carbaldehydes. these used as precursors for the synthesis of 2-(piperidin-1-yl) and/ or 2-(morpholin- 1-yl) quinoline derivatives through the reaction with active methyl and/ or methylene component, Claisen-Schmidt condensation, one-pot multicomponent reactions (MCRs), reductive amination, Grignard reaction, etc. Methods: This review demonstrates the synthesis of 2-chloroquinoline-3-carbaldehyde derivatives, through Vilsmeier-Haack formylation of N-arylacetamides that used as a precursor for preparation of 2-(piperidin-1-yl) and/ or 2-(morpholin-1-yl) quinoline- 3-carbaldehydes and reacted them with various reagents to form the 2-(piperidin-1-yl) and/ or 2-(morpholin-1-yl) quinolines derivatives. Results: Many 2-(piperidin-1-yl) and/ or 2-(morpholin-1-yl) quinolines derivatives were achived through the reaction with active methyl and/ or methylene component, Claisen-Schmidt condensation, one-pot multicomponent reactions (MCRs), reductive amination, Grignard reaction, etc…. Conclusion: Many quinoline ring systems, specifically concerning medicinal chemistry, had been published over the past decade. During this review, we have outlined the synthetic routes and reactions of 2-(piperidin-1-yl) and/ or 2-(morpholin-1-yl) quinoline-3-carbaldehydes. This review implies a section of the synthesis of 2-(piperidin-1-yl) and/ or 2-(morpholin-1-yl) quinoline-3-carbaldehydes which can be prepared via Vilsmeier formylation of N-arylacetamides followed by heating of the formed aldehydes with piperidine or morpholine and two sections on its reactions with different reagents were presented. Eventually, this review focus upon 2-(piperidin-1-yl) and/ or 2-(morpholin-1- yl) quinoline-3-carbaldehydes as an interesting heterocyclic compound that can be utilized as a precursor and building block for the synthesis of an extended range of heterocyclic systems which have a potent pharmacological interest.