Multilinker Phosphorous Acid Anchored En/MIL-100(Cr) as a Novel Nanoporous Catalyst for the Synthesis of New N-heterocyclic Pyrimidoquinolines

Nowadays, solid compounds with crystalline structure formed by inorganic clusters or metalions (generally transition metals) linked by two or multifunctional organic units, which calledmetal-organic frameworks (MOFs). In recent years, metal-organic frameworks (MOFs) arevaluable materials because of their applications on the preparation of adsorption, catalysis,sensors, electronics, selective separation, fuel cells, petrochemistry, large scale of industrialproducts and drug delivery [1-2]. N-Heterocyclic compounds such as uracil derivatives areone of the important categories of compounds in the organic synthesis. Quinoline and pyrimidinederivatives containing uracil in their structure are interesting classes of organic compoundsbecause of their pharmacological activity including antitumour, cardiotonic, hepatoprotactive,antihypertensive, antibronchitic and antifungal activity. Pyrimido[4,5-b]quinolonederivatives are a category of fused quinolines separated from the marine bacteria having antibacterialand antifungal activities [3-4]. In the present research, we explored MOFs chemicallymodified by organophosphonic acid MIL-100(Cr)/NHEtN(CH2PO3H2)2 based on En/MIL-100(Cr) by a heterogeneous synthetic method, and used it as a task-specific, recyclable andreusable catalyst for the operational and one-pot synthesis of new N-heterocyclic compoundssuch as tetrahydropyrimido[4,5-b]quinoline-2,4,6(1H,3H,7H)-trione, tetrahydropyrimido[4,5-b]quinoline-4,6(3H,7H)-dione and octahydropyrimido[4,5-b]quinolin-6(1H)-one derivatives(Fig. 1).