Cerium-based organic framework with aliphatic ligand as an excellent catalyst in the green synthesis of polysubstituted 1,8-naphthyridines

A novel cerium-based aliphatic Metal-Organic Framework (MOF) was hydrothermally synthesized from ceric ammonium nitrate (CAN) and hexamethylenediaminetetraacetic acid (HDTA). This highly crystalline MOF, often forming hollow tubes, and exhibits thermal stability up to 300 °C along with exceptional structural integrity. This catalyst facilitated the efficient green synthesis of polysubstituted 1,8-naphthyridines from 2,6-diaminopyridine, active methylene sources (malononitrile or ethyl cyanoacetate), and aromatic aldehydes. This condensation, performed in ethanol under green conditions, yielded high product yields across a broad range of functional groups. Critically, the catalyst demonstrated outstanding recyclability, retaining its catalytic performance over five consecutive cycles with no significant activity loss. This positions it as a highly promising heterogeneous and sustainable catalyst for environmentally benign chemical transformations.