Synthesis and Application of Imidazolium-Based Ionic Liquid Supported on Hydroxyapatite Encapsulated γ-Fe2O3 Nanocatalyst in Preparation of Pyrido[2,3-d]Pyrimidines

Synthesis of novel 2-amino-5-aryl-7-(1-methyl-1H-pyrrol-2-yl)-4-oxo-3,4,5,8-tetrahydro-pyrido[2,3-d]pyrimidine-6-carbonitrile derivatives is reported by the reaction of 2,6-diaminopyrimidin-4(3H)-one, 3-(1-methy-1H-pyrrol-2-yl)-3-oxopropane nitrile and aryl aldehydes in the presence of newly synthesized imidazolium based ionic liquid supported on hydroxyapatite encapsulated gamma-Fe2O3 nanocatalyst [gamma-Fe2O3@HAp-Si(CH2)(3)Cl@DMIM] in short reaction times (7-13 min) and high to excellent yields (80%-95%). Cleaner reaction profile, mild reaction conditions, use of the green solvent and reusability of the catalyst, make this protocol attractive for the large scale synthesis of pyrido[2,3-d]pyrimidine-6-carbonitrile derivatives and is amenable for iterative combinatorial library generation. The synthesized nanoparticles were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscope, energy dispersive analysis of X-rays, thermogravimetric analysis, differential thermogravimetric and vibrating sample magnetometer.