Leflunomide, a new antirheumatoid arthritis drug was synthesized from the starting material ethyl acetoacetate, triethyl orthoformate, acetic anhydride, etc. Synthesis of acetoacetate esters using a new catalyst& triethylamine 以乙酸乙酯、原甲酸三乙酯、乙酸酐等为起始原料经缩合、环化等五步反应合成了新型免疫调节抑制剂抗类风湿性关节炎新药来氟米特.用新型催化剂三乙胺合成乙酰乙酸酯