|Budget Amount *help
¥3,300,000 (Direct Cost : ¥3,300,000)
Fiscal Year 2004 : ¥1,400,000 (Direct Cost : ¥1,400,000)
Fiscal Year 2003 : ¥1,900,000 (Direct Cost : ¥1,900,000)
According to the research project written in the application form, the synthesis of antioxidants having both antioxidant activities in water-soluble vitamin C and properties in fat-soluble carotenoid astaxanthin, and measurement of their antioxidant activities were planned. On the basis of the research-conducting plan, synthesis of the target compound was carried out. Starting from commercially available α-ionone, its peracid-oxidation followed by acid-treatment gave 4-hydroxy-β-ionone which was converted to 3-hydroxy-4-keto-β-ionol derivative through six steps. Then, several trials of functionalization at C-2 position of 3-hydroxy-4-keto-compound was unsuccessful. It was supposed due to the steric hindrance of dimethyl groups at C-1 position. Therefore, 2-hydroxy-β-ionone TBSether was selected as starting material in the next trial. It was synthesized through 4 steps from 2,2,6-trimethylcyclohexane-1,3-dione prepared by literature's method. Introduction of oxygen fuctional group at C-4 in 2-hyroxy-β-ionone TBSether was not accomplished. Then, 2-hyroxy-β-ionone TBSether was transformed through 6 steps to 2-oxo-β-ionol TBSether whose TMSenol ether was oxidized with MCPBA followed by TsOH-treatment to provide 2-oxo-3-hydroxy-compound in good yield. It was transformed to 2-hydroxy-3-3-oxo-β-ionol diTBSether after conversion of functional groups by 5 steps. Finally, in order to introduce oxygen atom at C-4 position, several methodologies, which involve, for example, introduction of hydroxyl group via silyl enol ether or direct hydroxylation at α-position of carbonyl group, were tried. Unfortunately, target compound was not obtained.