One-pot three-component synthesis of pyrano[2,3-d] pyrimidines derivatives using silica-bonded ionic liquid as recyclable catalyst

Multi-component reactions (MCRs) achieve significant role in combinatorial chemistry due to the ability to prepare target compounds with more efficiency and atomic economy by the reaction of three or more compounds together in a single step [1]. In the recent years, ionic liquids (ILs) have become powerful alternatives to the conventional molecular organic solvents due to their particular properties such as the ability to dissolve many organic and inorganic substances [2]. Among them, basic ILs have attracted unparalleled attention because, compared to the combination of an inorganic base and an IL, they have represented more advantages such as high catalytic efficiency and simple catalyst recycling for some base-catalyzed processes [3]. Pyrano[2,3- d]pyrimidines have received considerable attention owing to their wide range of diverse pharmacological activity. They are nicotinic acid receptor (NAR) agonists and show antitumor, hepatoprotective, antibronchitic, and anti-AIDS activity, among others [4]. Here in, we have reported that the synthesis of pyrano[2,3- d]pyrimidines derivatives in the presence of silicapropyl-caffeine chloride ([SP-Caff]Cl) as a recyclable solid basic catalyst from the reaction of an aldehyde, malononitrile, and N, N′- dimethyl barbituric acid in water at 60 ºC.