Synthesis of methyl 4ª²fluorocinnamate with strongly acidic cationic exchange resin as catalyst

    CHENG Siª²Kun, ZHANG Shengª²Yong, JIANG Ru, Li Xiaoª²Ye

    Department of Chemistry, School of Basic Medicine, Fourth Military Medical University, Xi¬ðan 710033, China

    ¡¾Abstract¡¿AIM: To synthesize methyl 4ª²fluorocinnamate, which is widely used in asymmetric dihydroxylation and aminohydroxylation, by esterification of 4ª²fluorocinnamic acid and methanol with strongly acidic cationic exchange resin as catalyst. METHODS: A mixture of appropriate amount of 4ª²fluorocinnamic acid, methanol and pretreated cationic exchange resin was stirred vigorously and refluxed for 5 h. After the excess of methanol was removed by distillation, the residue was extracted. Resin was recovered by filtration of the organic layers and reused after washing and drying. The combined organic layers were further washed and dried to yield methyl 4ª²fluorocinnamate. The purity of methyl 4ª²fluorocinnamate was determined by thin layer chromatography and the product was characterized by melting point, infrared spectrum (IR) and 1H nuclear magnetic resonance spectroscopy (1H NMR). RESULTS: Optimum yield was 97.5% and the melting point, IR and 1H NMR of methyl 4ª²fluorocinnamate were in accordance with the data reported. CONCLUSION: The esterification with strongly acidic cationic exchange resin as catalyst is cost efficient, less erosive to equipment and can be used for largeª²scale preparation of chiral medicinal materials. ......