Metal Complexes with Naphthalene-Based Acetic Acids as Ligands: Structure and Biological Activity

Naproxen (6-methoxy-α-methyl-2-naphthaleneacetic acid), 1-naphthylacetic acid, 2-naphthylacetic acid and 1-pyreneacetic acid are derivatives of acetic acid bearing a naphthalene-based ring. In the present review, the coordination compounds of naproxen, 1- or 2-naphthylacetato and 1-pyreneacetato ligands are discussed in regard to their structural features (nature and nuclearity of metal ions and coordination mode of ligands), their spectroscopic and physicochemical properties and their biological activities.

One-pot synthesis of new alkyl 1-naphthoates bearing quinoline, pyranone and cyclohexenone moieties via metal-free sequential addition/oxidation reactions

A mild and one-pot synthetic pathway was successfully developed for the synthesis of new naphthoate-based scaffolds containing quinoline, pyranone and cyclohexenone moieties via a multistep reaction between acenaphthoquinone and various 1,3-diketones in the presence of different primary aliphatic and benzylic alcohols. This reaction proceeds via a sequential addition/oxidation mechanistic process including a metal-free addition step of acenaphthoquinone and 1,3-diketones followed by the H₅IO₆-mediated C–C oxidative cleavage of the corresponding vicinal diols at room temperature. The alcohols play a dual role, as the reaction solvent as well as the nucleophile, to conduct the reaction process toward naphthoate formation. All alkyl naphthoate derivatives prepared in this work are new compounds and were definitively characterized using ¹H-NMR, ¹³C-NMR and HRMS analysis, while X-ray crystallography was carried out for one of the products. The synthesis of a naphthalene-based nucleus attached to heterocyclic moieties is noteworthy to follow in the near future for diverse applications in biology, medicine, metal complex design, and semiconductor and optical materials.

Various new alkyl 1-naphthoates bearing quinoline, pyranone and cyclohexenone moieties were successfully synthesized by a one-pot sequential addition/oxidation process.