The multicomponent reaction mechanisms of prop-2-en-1-amine and ethyl propiolate with alloxan were studied using density functional theory. The reaction mechanisms were found to consist of two stages. First, the prop-2-en-1-amine reacts with ethyl propiolate to form an beta-aminoacrylate through two competitive channels (channels a and b). Second, a nucleophilic addition of beta-aminoacrylate to alloxan occurs via four possible channels (channels b1, b2, b3 and b4). The calculated results revealed that the most energetically favorable path is channel b4 and suggested that the water molecule plays as a proton transfer intermediate in the reaction. Our calculations demonstrated that the reaction occurs easily at room temperature, which agrees well with the experiment. (C) 2010 Elsevier B.V. All rights reserved.