A green approach for an efficient preparation of 2,4-diamino-6-aryl-5-pyrimidinecarbonitriles using a TiO2–SiO2 nanocomposite catalyst under solvent-free conditions

We report on the preparation of a series of 2,4-diamino-6-aryl-5-pyrimidinecarbonitriles, a new efficient protocol, via the condensation reaction of aromatic aldehydes, malononitrile, and guanidine nitrate using a TiO2–SiO2 nanocomposite with a molar ratio of 1:1 as a heterogeneous catalyst. The use of a low-cost and reusable catalyst under mild and solvent-free conditions, and simplicity in operation with easier isolation of the products in high to excellent yields are the main advantages of this highly versatile and eco-friendly protocol.