Thiazole Functionalized Porous Metal‐Organic Framework‐Based Catalyst for Solvent‐Free Synthesis of Biologically Important Quinoline Derivatives Through Friedlander Condensation

The demand for quinoline derivatives is increasing rapidly owing to their extensive use in the synthesis of pharmaceutically active compounds. In this work, a thiazole-functionalized zirconium(IV) based metal-organic framework (MOF) was utilized to synthesize quinoline derivatives through catalytic Friedlander condensation. The synthesized MOF (1) exhibited good thermal stability and remained stable in diverse chemical environments. The as-synthesized MOF was activated to obtain guest-free 1', and its porous nature was thoroughly investigated. The catalyst 1' facilitated the selective diffusion of the targeted substrate. Moreover, the strategic design of MOF 1' enables the incorporation of both Lewis acidic and basic sites in a single catalyst, which led to high conversion of the product via activation of substrates. The designed heterogeneous catalyst efficiently synthesized quinoline moiety under a solvent-free medium at 100°C for 18 h with 92% conversion of the product. In addition, 1' exhibited a wide substrate and was also reusable up to the third catalytic cycle with minimum loss of catalytic efficiency. The role of active sites within the catalyst was verified through control experiments. This study highlights the potential of MOFs as heterogeneous catalysts for the sustainable synthesis of quinoline derivatives, offering a promising alternative to conventional homogeneous catalysts.