A Study On The Synthesis Of Cinnamic Acid And Its Derivatives

Cinnamic acid and its derivatives have been widely used in food, medicine, household chemicals and other areas, but they were also important intermediates in fine organic synthesis. The molecular structure of cinnamic acid can be designed, other groups can be introduced into the benzene ring, for example, hydroxy, methoxy, nitro and other groups; carboxyl can synthesize ester, acid halide, amide by Esterification reaction or Acylation reaction. On this basis, a series of compounds were synthesized, for example, cinnamic acid, p-hydroxycinnamic acid, p-methoxycinnamic acid, cinnamoyl glycine and p-methoxycinnamoyl alanine, the reaction mechanisms and synthesis of these compounds were discussed.(1) Cinnamic acid was synthesized by benzaldehyde and acetic anhydride under Perkin reaction, which was catalyzed by potassium carbonate. The reaction condition was optimized, and the yield of cinnamic acid was 56.1%. The structure of the product was identified by Fourier Transform Infrared Spectrometer (FT-IR), Superconducting Nucleus Magnetic Resonance Spectrometer (1H NMR) and Micro melting point instrument.(2) P-hydroxycinnamic acid was synthesized under microwave irradiation or conventional heating by p-hydroxybenzaldehyde, acetic anhydride and potassium carbonate under Perkin reaction. The reaction condition was optimized, and the result showed that the maximum yield of p-hydroxycinnamic acid reached 71.9%. Meanwhile, the effects of different heating methods on p-hydroxycinnamic acid synthesis were discussed. The structure of the product was identified by Fourier Transform Infrared Spectrometer (FT-IR), Superconducting Nucleus Magnetic Resonance Spectrometer (1H NMR) and Micro melting point instrument.(3) P-methoxycinnamic acid was synthesized by anisic aldehyde and acetic anhydride under Perkin reaction, which was catalyzed by potassium carbonate. The reaction condition was optimized. The yield of cinnamic acid was 39.7%. The structure of the product was identified by Fourier Transform Infrared Spectrometer (FT-IR), Superconducting Nucleus Magnetic Resonance Spectrometer (1H NMR) and Micro melting point instrument.(4) Substituted cinnamic acid (homemade) and thionyl chloride were used as raw materials to prepare substituted cinnamoyl chloride, then cinnamoyl glycine and p-methoxycinnamoyl alanine were synthesized by substituted cinnamoyl chloride, amino acid (glycine, DL-alanine) and sodium tripolyphosphate. With the synthesi of cinnamoyl glycine as an example, we obtained the better reaction condition, and the yields of two compounds were 75.3% and 74.3%. The products were characterized by Fourier Transform Infrared Spectrometer (FT-IR), Superconducting Nucleus Magnetic Resonance Spectrometer (1H NMR、13C NMR).