Recent Advances in the Synthesis of Coumarin Derivatives via Pechmann Condensation

Prospecting for cytotoxic and antiprotozoal 4‐aryl‐4H‐chromenes and 10‐aryldihydropyrano[2,3‐f]chromenes

“…Therefore, a series of related compounds were designed as shown in Figure (drawing 2) by considering various structural changes characterized by other aryl substituents on the sp 3 CH group, the switch of the nitrile function to the methyl carboxylate group, and the introduction of a second chromene ring. Therefore, phloroglucinol was used as phenolic precursor for the coumarin synthesis via Pechmann condensation (Scheme ) in a solvent‐free condition . Thereafter, the coumarin ( 3 ) was treated with malonitrile and different aromatic aldehydes in an alkaline medium (K 2 CO 3 ) to afford 10‐aryl‐2,10‐dipyranochromenes 4 – 9 in a one‐pot manner (Scheme ).…”

“…[1,[13][14][15] Therefore, a series of related compounds were designed as shown in Figure 1 Therefore, phloroglucinol was used as phenolic precursor for the coumarin synthesis via Pechmann condensation (Scheme 1) in a solvent-free condition. [16] Thereafter, the coumarin (3) was treated with malonitrile and different aromatic aldehydes in an alkaline medium (K 2 CO 3 ) to afford 10-aryl-2,10-dipyranochromenes 4-9 in a one-pot manner (Scheme 2). Another set of pyranocoumarins derivatives (10)(11)(12)(13)(14) was obtained by using the same synthetic conditions and by treating 3 with methyl α-cyanoacetate ester and different aromatic aldehydes (Scheme 3).…”

“…4-Aryl-4H-chromenes containing halogens and a NO 2 group (16)(17)(18) were cytotoxic against CCRF-CEM cells with almost the same strength. However, compound 18 bearing a NO 2 group was twofold less active on CEM/ADR5000 cells than 16 and 17.…”

Natural Organic Acid as Green Catalyst for Xanthenones Synthesis: Methodology, Mechanism and Calcium Channel Blocking Activity

“…Oxalic acid was reported as an efficient catalyst for the synthesis of coumarins, 31 quinoxalines, 32 quinolines, 33 bis(indolyl)methanes, 34,35 tetrahydroquinolines 36 and flavone. 37 Although less explored in multicomponent reactions, oxalic acid has also shown to be an efficient catalyst in such reactions for obtaining quinazolinones, 38 piperidines 39 and N-aryl-3-aminodihydropyrrol-2-one-4-carboxylates compounds. 40 Malonic acid was reported as a catalyst in polymerization reactions 41,42 and for obtaining 1,3-dichloropropanols from glycerol; 43 however, its use in multicomponent reactions has not been described yet.…”

Synthesis of 2‐aryl‐1‐arylmethyl‐1H‐1,3‐benzimidazoles catalysed by ferric ammonium sulfate (NH4Fe(SO4)2) under solvent‐free conditions

“…Because of their importance, the synthesis of substituted benzimidazoles has become a focus of synthetic organic chemistry. Various oxidative and catalytic reagents such as 2,3‐dichloro‐5,6‐dicyanobenzoquinone, MnO 2 , ionic liquids, alumina–methanesulfonic acid, diacetoxyiodobenzene, Yb(OTf) 3 , silica sulfuric acid, oxalic acid, N ‐bromosulfonamide, N ‐iodosulfonamide, Co/Mn nanoparticles, 2,4,6‐trichloro‐1,3,5‐triazine and silica phenylsulfonic acid have been employed to effect this transformation. However, a number of these methods have some drawbacks such as low yields, the use of expensive reagents or chlorinated organic solvents, and harsh reaction conditions.…”