Tumor has been one of the main diseases that threaten the health of human. The main treatment measure is chemotherapy. Multidrug resistance (MDR) of tumor cells to chemotherapeutic agents is known to be the main reason for treatment failure in cancer chemotherapy. So MDR has become a focus in the field of medicine science.The mechanism of MDR mediated by glutathione S-transferases (GSTs) is an important one of the drug resistance development of human tumor cells. In various kinds of GST isozyme, human GSTπ (hGSTπ , GSTP1-1) serves two different roles in the development of resistance toward chemotherapy agents through acting as phase II detoxification enzymes, and as regulators of the mitogen-activated protein kinase (MAPK) pathway. Therefore, GSTP1-1 has been a novel target in the research of multidrug resistance reversal agents of tumor cells.Ethacrynic acid (EA), an α, β-unsaturated carbonyl derivative, has been proved to be a effective GSTπ inhibitor which can enhance the cytotoxicity of chemotherapeutic agents towards drugresistant tumor cells. EA has been used to treat advanced tumor in combination with thiotepa, and the sensitivity of tumor cells to thiotepa is enhanced. But its side effects limit its clinical use. Taking EA as a leading compound, basing on the initial study of structure-activity relationships (SAR), our laboratory has designed and synthesized 21 α, β-unsaturated carbonyl compounds. Their inhibitory activities on GSTP1-1 and growth inhibition on tumor cells have been measured. These compounds are not reported before and the chemical structures of these compounds have been