Abstract:
Synthesis of a novel UVA filter, 1,7-bis(3,4-dimethoxyphenyl)-4-methyl-1,6-heptadiene-3,5-dione, could be done by methylation of curcumin via curcumin via nucleophilic substitution reaction. The obtained 1,7-bis(3,4-dimethoxyphenyl)-4-methyl-1,6-heptadiene-3,5-dione possessed UVA absorption property with maximum absorption at 345 nm. The compound was viscous orange-yellow liquid. This compound could be dissolved in various organic solvents giving yellow solutions. The problem of solubility and deep orange color of curcumin could, therefore, be solved. Another novel UVA filter, 1,7-bis(3,4-dihydroxyphenyl)-4-methyl-1,6-heptadiene-3,5-dione was also prepared from curcumin. This latter compound possessed not only UVA absorption property but also showed similar antioxidant activity to curcumin. Both 1,7-bis(3,4-dimethoxyphenyl)-4-methyl-1,6-heptadiene-3,5-dione and 1,7-bis(3,4-dihydroxyphenyl)-4-methyl-1,6-heptadiene-3,5-dione were photostable.