Facile four component synthesis of pyrido[2,3-d:6,5-d′]-dipyrimidines catalyzed by [HNMP]+[HSO4]- in water

Multicomponent reactions (MCRs) are of importance in synthetic organic chemistry as they can produce complex molecules with greater efficacy and atom economy from three or more starting materials in a one step without isolation of intermediates1-2. MCRs have been shown to be environmentally friendly as they minimize the number of synthetic steps and workups, and eliminate isolation unstable intermediates. In addition, the synthesis of a broad range of complex products can be achieved by MCRs such as; knoevenagel condensation, and intermolecular cycloaddition, metathesis, aza-Wittig and Mitsunobu reaction thetic2.A simple, efficient method for the synthesis of pyrido[2,3-d:6,5-d’]dipyrimidine derivatives via one-pot four-component reaction of aromatic aldehydes (1), 2-thiobarbituric acid (2), ammonium aetate (3) in the presence of a catalytic amount of [H-NMP]+[HSO4]- in water at room temperature is reported (Fig. 1). The process proved to be simple, environmentally friendly, efficient and high to excellent yielding. Moreover, some of the synthetic compounds were investigated and revealed important antimicrobial activity of prepared products.

Keywords:

Multicomponent reactions , Pyrido-dipyrimidines , Knoevenagel condensation , Aldehyde , 2-Thiobarbituric acid.