An Efficient and Versatile Deep Eutectic Solvent-Mediated Green Method for the Synthesis of Functionalized Coumarins

Abstract

Herein, we report a green and efficient synthetic route for the construction of diverse functionalized coumarins in good-to-excellent yields (60–98%) via the Pechmann condensation. The optimized synthetic route involves a biodegradable, reusable, and inexpensive deep eutectic solvent (DES) of choline chloride and l -(+)-tartaric acid in a ratio of 1:2 at 110 °C. Interestingly, phloroglucinol and ethyl acetoacetate, upon reaction, furnished the functionalized coumarin ( 20 ) in 98% yield within 10 min. On the other front, the same DES at relatively lower reaction temperature (90 °C) was found to provide the bis-coumarins in decent yields (81–97%) within 20–45 min. Moreover, this particular method was found to be quite effective for large-scale coumarin synthesis without noteworthy reduction in the yields of the desired products. Noticeably, in this versatile approach, the DES plays a dual role as solvent as well as catalyst, and it was effectively recycled and reused four times with no significant drop-down in the yield of the product.

Cyclodextrin-Based Sensors for the Recognition of Small Molecules

“…As coumarin and pyrene scaffolds are of great importance, owing to their vital role in biological systems and sensing arena as well [73]. In this regard, Ueno's group has synthesized β-CD-peptide hybrid polymeric conjugate (55), having pyrene as a donor moiety and coumarin as an acceptor one (Figure 15) [74,75].…”

Deep Eutectic Solvent (DES)-Mediated One-Pot Multicomponent Green Approach for Naphthalimide-Centered Acridine-1,8-dione Derivatives and Their Photophysical Properties

“…Among the diverse green and sustainable surrogates, − deep eutectic solvents (DESs), for the first time realized by Abbott’s group in 2003, have been continuously drawing a lot of attention of researchers globally, which can be inspected by a flow of scientific papers appearing in the literature day by day . The DESs in addition to exhibiting dual/triple features (solvent, catalyst, and/or reactant) in a reaction medium under consideration also display remarkable signatures including biodegradability, biocompatibility, atom economy, nonflammability, thermal stability, renewability, inexpensiveness, ease of handling, etc . − Taking the above-said and other, if any, amazing features of DESs into consideration and with our current research interest toward the development of green protocols for simple and interesting molecules using DESs, − herein, for the first time, we report a DES-mediated one-pot green synthesis of naphthalimide-centered acridine-1,8-dione derivatives through a multicomponent reaction of dimedone/cyclohexan-1,3-dione, hydrazine hydrate, 1,8-naphthanoic anhydride, and aromatic aldehydes. We believe that this useful eco-friendly methodology will open up new prospects for the construction of novel heterocyclic compounds in general and various interesting naphthalimide- and acridine-based conjugate molecular systems in particular.…”

Cesium salt of tungstophosphoric acid/mesoporous (zirconia–silica) composite for highly efficient synthesis of 7-hydroxy-4-methyl coumarin and removal of methylene blue

“…Coumarins which found in a variety of natural materials and are commonly used as a starting material or intermediary in the pharmaceutical, fragrance, and agrochemical industries. 41 It is also employed in the dispersed uorescent, optical brighteners, production of anticoagulants, pesticides, and insecticides, as well as additives in cosmetics and food. 2,42,43 Moreover, coumarins have been shown to exhibit a variety of bioactivities, including antibacterial, anticancer, and platelet aggregation inhibitory properties.…”