Diethyl　2,6-dimethyl-4-aryl-4H-pyran-3,5-dicarboxylates　(1)　have　been　synthesized　by　the　reaction　of　aryl　aldehyde　and　1,3-diketone　catalyzed　by　ZnCl2　under　ultrasound　irradiation.　The　effects　of　changes　in　the　ultrasonic　power,　temperature,　and　reaction　time　are　discussed.　With　the　optimized　reaction　conditions,　various　aryl　aldehydes　were　used　to　synthesize　4H-pyrans　(1)　under　the　influence　of　ultrasound　irradiation.　Compared　with　the　conventional　thermal　methods,　the　remarkable　advantages　of　this　method　are　the　simple　experimental　procedure,　shorter　reaction　time　and　high　yield　of　product.　(C)　2009　Elsevier　B.V.　All　rights　reserved.