Overview of coumarin-fused-coumarins: synthesis, photophysical properties and their applications

Coumarin-fused-coumarins have attracted significant attention in the scientific world owing to their boundless applications in interdisciplinary areas. Various synthetic pathways have been developed to construct novel coumarin-fused-coumarin analogues by the fusion of modern methodologies with a classical Pechmann reaction or Knoevenagel condensation. Owing to their extended molecular framework, they possess interesting photophysical properties depending on the fused coumarin ring systems. This review highlights previously published reports on the synthetic strategies for structurally diverse coumarin-fused-coumarins. Furthermore, the scope of the synthesized biscoumarin-fused entities is described by highlighting their photophysical properties and applications.

Synthesis of 3,15-Disuccinate-12-Coumarin Substituted Andrographolide Derivatives and Their Antiplatelet Aggregation Activities In Vitro

In order to develop a series of novel compounds with antiplatelet aggregation activities, 3,15-disuccinate-12-coumarin substituted derivatives were designed and synthesized based on the natural product andrographolide. In vitro antiplatelet aggregation activities were evaluated by the turbidimetric method with thrombin, adenosine diphosphate (ADP), arachidonic acid (AA), and collagen as inducers. The biological evaluation revealed that compound 11k showed significant inhibition activity for thrombin, AA, and collagen-induced platelet aggregation at the same time and exhibited a dose-dependent behavior. Compound 11c showed the highest antiplatelet aggregation activity induced by ADP. Most of the derivatives had no significant cytotoxicity. Therefore, our work proved that 3,15-disuccinate-12-coumarin substituted andrographolide derivatives had the potential to become a novel candidate structure for antiplatelet aggregation and deserved further study.

Photophysical properties and photodynamic anti-tumor activity of corrole-coumarin dyads

A new non-conjugated corrole-coumarin dyad and its gallium complex has been synthesized. Photophysical properties of the dyads were tested in two solvents, exhibiting strong solvent effect on the absorption and fluorescence spectra. Absorption spectra of the dyads are a linear combination of the spectra of their corresponding monomers, demonstrating a negligible electronic communication between coumarin and corrole moiety. However, fluorescence emission of coumarin entity in all dyads were quenched significantly as compared to pristine coumarin; this was attributed to intramolecular energy transfer from coumarin to the corrole. Photodynamic anti-tumor tests revealed that gallium corrole-coumarin dyads (2-Ga) exhibited good PDT activity towards SiHa cells. After PDT treatment, 2-Ga could induce apoptosis in SiHa cells, which was associated to cell S phase arrest, collapse of the mitochondrial membrane potential and increase of the intracellular ROS level.

Coumarin-Tetrapyrrolic Macrocycle Conjugates: Synthesis and Applications

This review covers the synthesis of coumarin-porphyrin, coumarin-phthalocyanine and coumarin-corrole conjugates and their potential applications. While coumarin-phthalocyanine conjugates were obtained almost exclusively by tetramerization of coumarin-functionalized phthalonitriles, coumarin-porphyrin and coumarin-corrole conjugates were prepared by complementary approaches: (a) direct synthesis of the tetrapyrrolic macrocycle using formylcoumarins and pyrrole or (b) by functionalization of the tetrapyrrolic macrocycle. In the last approach a range of reaction types were used, namely 1,3-dipolar cycloadditions, hetero-Diels-Alder, Sonogashira, alkylation or acylation reactions. This is clearly a more versatile approach, leading to a larger diversity of conjugates and allowing the access to conjugates bearing one to up to 16 coumarin units.

Synthesis of Corroles and Their Heteroanalogs

Corroles have come a long way from being a curiosity to being a mainstream research topic. They are now regularly synthesized in numerous research laboratories worldwide with diverse specific aims in mind. In this review we present a comprehensive description of corroles' synthesis, developed both before and after 1999. To aid the investigator in developing synthetic strategies, some of the sections culminate in tables containing comparisons of various methodologies leading to meso-substituted corroles. The remaining challenges are delineated. In the second part of this review, we also describe the syntheses of isocorroles and heteroanalogs of corroles such as triazacorroles (corrolazines), 10-heterocorroles, 21-heterocorroles, 22-heterocorroles, N-confused corroles, as well as norcorroles. The review is complemented with a short outlook.

Gallium(iii)corrole–BODIPY hybrid: novel photophysical properties and first observation of B–F⋯F interactions

Anchoring a BODIPY onto Ga(iii)corrole via a meso-β linkage facilitated PeT in polar solvents, which quenched the fluorescence, and is further confirmed by electrochemical studies.

New meso-substituted corroles possessing pentafluorophenyl groups – synthesis and spectroscopic characterization

In this paper, the synthesis and spectroscopic characterization of new free-base corroles substituted with different peripheral groups are reported.

Pentacyclic coumarin-based blue emitters – the case of bifunctional nucleophilic behavior of amidines

Esters of coumarin-3-carboxylic acids undergo addition to DBU and DBN leading to the formation of a 6-membered ring.

From π-expanded coumarins to π-expanded pentacenes

Dihydroxyanthraquinone can be transformed into head-to-tail bis-coumarins which undergo photo-dehydrogenative coupling leading to coronene derivatives.

Vertically π-expanded coumarin – synthesis via the Scholl reaction and photophysical properties

A short and efficient access to a unique type of π-expanded coumarin is achieved.