Ligand-free palladium-catalyzed intramolecular arylation of chromones: an expedient synthesis of 1-benzopyrano[3,2-c]quinolines

Synthesis and Biological Activity of Chromeno[3,2-c]Pyridines

The review summarizes all synthetic methodologies for the preparation of chromeno[3,2-c]pyridines and chromeno[3,2-c]quinolines. The proposed approaches are systemized based on ways for the construction of the heterocyclic system. The presence of these compounds in nature and their bioactivity are also discussed. Natural products with an annelated chromeno[3,2-c]pyridine fragment are well-known and a number of alkaloids derived from this system as a key core have been recently isolated. These compounds demonstrate antimicrobial, antivirus, and cytotoxic activities, making chromeno[3,2-c]pyridine structural motifs promising for medicinal chemistry.

A one-pot three-component reaction involving 2-aminochromone in aqueous micellar medium: a green synthesis of hexahydrochromeno[2,3-b]quinolinedione

An efficient and green synthesis of hitherto unreported 11-(chromen-3-yl)-8,8-dimethyl-8,9-dihydro-6H-chromeno[2,3-b]quinoline-10,12(7H,11H)-dione has been accomplished by a three-component reaction involving 2-aminochromone, chromone-3-carbaldehyde, and 5,5-dimethyl-1,3-cyclohexanedione (dimedone) in 0.5 M aqueous SDS solution. The mechanism of the reaction has been studied by isolating the reaction intermediate. This methodology features eco-friendly reaction conditions, a simple working procedure, high atom-economy and high efficiency in product formation.

Metal-mediated post-Ugi transformations for the construction of diverse heterocyclic scaffolds

The Ugi-4CR is by far one of the most successful multicomponent reactions leading to high structural diversity and molecular complexity. However, the reaction mostly affords a linear peptide backbone, enabling post-Ugi transformations as the only solution to rigidify the Ugi-adduct into more drug like species. Not surprisingly, the development of these transformations, leading to new structural frameworks, has expanded rapidly over the last few years. As expected, palladium-catalyzed reactions have received the foremost attention, yet other metals, particularly gold complexes, are fast catching up. This tutorial review outlines the developments achieved in the past decade, highlighting the modifications that are performed in a sequential or domino fashion with emphasis on major concepts, synthetic applications of the derived products as well as mechanistic aspects.

Palladium nanoparticles in glycerol: a clear-cut catalyst for one-pot multi-step processes applied in the synthesis of heterocyclic compounds

Palladium/TPPTS nanoparticles in glycerol represent a versatile catalyst leading to a large variety of heterocycles through domino/sequential one-pot approaches.

Synthesis of 3-tetrazolylmethyl-4H-chromen-4-ones via Ugi-azide and biological evaluation against Entamoeba histolytica, Giardia lamblia and Trichomona vaginalis

The synthesis of novel 3-tetrazolylmethyl-4H-chromen-4-ones via an Ugi-azide multicomponent reaction and their biological evaluation against Entamoeba histolytica, Giardia lamblia and Trichomona vaginalis are described. Reported yields are moderate to good and biological results show that these compounds could be considered as candidates to anti-parasitic drugs, especially against G. lamblia.