A series of new 3-pyrimidin-5-ylpropanamides was selectively synthesized via a microwave-assisted, chemoselective reaction of arylidene-Meldrum's acid, 6-hydroxypyrimidin-4(3H)-one, and structurally diverse amines including (S or R)-1-phenylethanamine, cyclohexanamine, and cyclopentanamine depended on nature of solvents. In this reaction, the utilization of HOAc as a solvent leads to 3-pyrimidin-5-ylpropanamides, whereas water as reaction media results in the spiro[5.5]undecane-1,5,9-triones from same starting materials. This method has the advantages of short synthetic route, operational simplicity, increased safety for small-scale high-speed synthesis, and minimal environment impact.