Transition Metal-Free Chemoselective Synthesis of Quinaldic Acid Derivatives via One-Pot Assembly: Assessment of their Photophysical Properties

Abstract

A convenient and metal-free one-pot sustainable procedure has been devised for the synthesis of fluorescent quinaldic acid derivatives from (Z)-alkyl 2-chloro-4-oxobut-2-enoates and aromatic amines. By employing this strategy, a library of 29 molecules of 2-quinaldic acid derivatives with diverse substitution patterns was created. We have also demonstrated the scope of strategy for the synthesis of heterocycles like oxabicyclo[2.2.1]hept-5-enes, oxazole, and diverse building blocks, including quinoline-2-carbaldehyde, quinoline-2-carbohydrazide, quinoline-2-amides, allylic alcohol, as well as azido aldehyde. Moreover, quinaldic acid derivatives exhibited significant luminescent properties with a quantum yield (ΦF) up to 33%.