Synthesis of Asymmetric Curcumin Analogue (2,6)-2-(3-bromo-4-methoxybenzylidine)-6-(3,4-dimethoxybenzylidine)cyclohexanone with a Base Catalyst

Abstract

Curcumin analogs are phenolic secondary metabolites that are more stable than curcumin because they do not contain active methylene groups. Generally, these compounds have a symmetric structure, while asymmetric curcumin analogs with higher frequency and potency are rarely synthesized. This study aimed to synthesize asymmetric curcumin analogs from 2-(3,4-dimethoxybenzylidene)cyclohexanone and bromoanisaldehyde. The synthesis was conducted using the Claisen-Schmidt condensation method with a base catalyst in ethanol at 25 °C for 12 hours. The intermediate compound available in the laboratory was characterized using GC-MS, showing a molecular ion (M⁺) at m/z 246. Meanwhile, bromoanisaldehyde was characterized by GC-MS and FT-IR, yielding a molecular ion at m/z 215 and a C–Br stretching vibration peak at 812 cm⁻¹. The study yielded a yellow solid weighing 0.13 g (yield percentage: 2.93%) with a melting point of 143-147 °C. UV-Vis, FT-IR, and HR-MS analysis confirmed the successful synthesis and characterization of the asymmetric curcumin analog, as evidenced by the molecular ion (M⁺) at m/z 443.06274 in the HR-MS spectrum. However, further analysis, such as ¹H-NMR and ¹³C-NMR, is needed to confirm the structure of the compound. Furthermore, research related to bioactivity testing is crucial for obtaining more stable and effective drug candidates.