Synthesis and Antifungal Activity of 4‐ and 6‐(1H‐Pyrrol‐1‐yl) Coumarins, and their Thiocyanato Derivatives

Abstract

Facile and efficient syntheses of 4‐(1H‐pyrrol‐1‐yl)‐coumarins and 6‐(1H‐pyrrol‐1‐yl)‐coumarins from the corresponding aminocoumarins are reported. The transformations were optimized and their corresponding scope and limitations were assessed. Selected (1H‐pyrrol‐1‐yl)‐coumarins were further subjected to a mild thiocyanation, undergoing selective functionalization on the pyrrole nucleus. A set of 10 differently substituted compounds was submitted to activity testing against various fungal strains. It was found that the introduction of a SCN moiety increased the antifungal activity, turning some compounds into fungicidal agents, to the point that one of the thiocyanato derivatives displayed an antifungal profile comparable to those of fluconazole and nystatin.

Cascade Synthesis of Pyrroles from Nitroarenes with Benign Reductants Using a Heterogeneous Cobalt Catalyst

“…In the presence of 1.8 mol % Co/NGr‐C@SiO 2 ‐L under solvent‐free conditions, the starting nitroarenes were converted to their corresponding N‐phenylpyrroles. In addition to chemical building blocks, this cascade reaction can be easily used to prepare biologically active compounds such as 37 and 38 which are known for their anti‐HIV and antifungal activities . Notably, the acidic nature of formic acid allows for expansion of the reaction scope to include previously inaccessible substrates with basic N‐atoms, including pyridines ( 40 ), benzimidazoles ( 39 ), pyrazoles ( 41 ) and 1,10‐phenanthroline ( 42 ).…”

“…In the presence of 1.8 mol %Co/NGr-C@SiO 2 -L under solvent-free conditions,t he starting nitroarenes were converted to their corresponding N-phenylpyrroles.I na ddition to chemical building blocks,t his cascade reaction can be easily used to prepare biologically active compounds such as 37 and 38 which are known for their anti-HIV and antifungal activities. [31] Notably,t he acidic nature of formic acid allows for expansion of the reaction scope to include previously inaccessible substrates with basic N-atoms,i ncluding pyridines (40), benzimidazoles (39), pyrazoles (41)a nd 1,10phenanthroline (42). When piperazine substrate 43 was tested under the optimized reaction conditions,t he hydrogenation of nitro group and subsequent pyrrole formation proceeded smoothly.However,the secondary amine was formylated with HCOOH giving product 44 in 54 %yield.…”

Synthesis and Antifungal Activity of Some Novel Coumarin‐Amino Acid Conjugates

“…[15,16] They are also well documented for their antifungal activities. [17][18][19] On the other hand, due to their structural diversity and functional versatility amino acids have received considerable attention in pharmaceutical research. In recent years many studies have explored the effect of combination of amino acids with other pharmacophoric groups on the biological activity.…”

“…Coumarins have been found to possess anticancerous, antimicrobial, antiviral, anti‐inflammatory, antitubercular and antioxidant activities [15,16] . They are also well documented for their antifungal activities [17–19] …”

Solvent Free Three-Component Synthesis of 2,4,5-trisubstituted-1H-pyrrol-3-ol-type Compounds from L-tryptophan: DFT-B3LYP Calculations for the Reaction Mechanism and 3H-pyrrol-3-one↔1H-pyrrol-3-ol Tautomeric Equilibrium

“…Several studies employing hybrid heterocyclic systems have led to a synergistic effect, expanding the scope on their biological activities [ 10 , 11 , 12 , 13 ]. Novel derivatives of pyrano[2,3- b ]pyridine and pyrrolo[2,3- b ]pyrano[2,3- d ]pyridine proved to be active against Candida sp.…”