The green chemistry of chalcones: Valuable sources of privileged core structures for drug discovery

The sustainable use of resources is essential in all production areas, including pharmaceuticals. However, the aspect of sustainability needs to be taken into consideration not only in the production phase, but during the whole medicinal chemistry drug discovery trajectory. The continuous progress in the fields of green chemistry and the use of artificial intelligence are contributing to the speed and effectiveness of a more sustainable drug discovery pipeline. In this light, here we review the most recent sustainable and green synthetic approaches used for the preparation and derivatization of chalcones, an important class of privileged structures and building blocks used for the preparation of new biologically active compounds with a broad spectrum of potential therapeutic applications. The literature here reported has been retrieved from the SciFinder database using the term "chalcone" as a keyword and filtering the results applying the concept: "green chemistry", and from the Reaxys database using the keywords "chalcone" and "green". For both databases the time-frame was 2017-2022. References were manually selected based on relevance.

1,8-naphthyridine derivatives: an updated review on recent advancements of their myriad biological activities

Among all nitrogen-containing heterocycles, the 1,8-naphthyridine scaffold has recently gained an immense amount of curiosity from numerous researchers across fields of medicinal chemistry and drug discovery. This new attention can be ascribed to its versatility of synthesis, its reactiveness and the variety of biological activities it has exhibited. Over the past half-decade, numerous diverse biological evaluations have been conducted on 1,8-naphthyridine and its derivatives in a quest to unravel novel pharmacological facets to this scaffold. Its potency to treat neurodegenerative and immunomodulatory disorders, along with its anti-HIV, antidepressant and antioxidant properties, has enticed researchers to look beyond its broad-spectrum activities, providing further scope for exploration. This review is a consolidated update of previous works on 1,8-naphthyridines and their analogs, focusing on the past 5 years.

Fused chromeno and quinolino[1,8]naphthyridines: Synthesis and biological evaluation as topoisomerase I inhibitors and antiproliferative agents

The synthesis of 1,8-naphthyridine derivatives fused with other heterocycles, such as chromenes and quinolines, as well as their behaviour as topoisomerase I inhibitors is studied. The preparation is carried out through a direct and simple process as an intramolecular [4 + 2] cycloaddition reaction between functionalized aldimines, obtained by the condensation of 2-aminopyridine and unsaturated aldehydes, and olefins. In particular, while no clear inhibitory activity is observed for chromeno[4,3-b][1,8]naphthyridine fused heterocycles, a very different result is observed for quinolino[4,3-b][1,8]naphthyridine derivatives. Experimental assays indicated that quinolino[4,3-b][1,8]naphthyridines inhibited the topoisomerase I enzymatic reaction behaving like a poison, as occurs with the natural TopI inhibitor, camptothecin. Furthermore, the cytotoxic effect on cell lines derived from human lung adenocarcinoma (A549), human ovarian carcinoma (SKOV3), and on non-cancerous lung fibroblasts cell line (MRC5) was also screened.