Synthesis and antioxidant activity of rosmariquinone and several analogues
Synthesis and antioxidant activity of rosmariquinone and several analogues
复制标题
DOI：
10.1021/jf970742k
复制
发表时间：
1998-04-01
影响因子：
6.1
通讯作者：
Dussault, P
中科院分区：
文献类型：
--
作者：
Hall, CA;Cuppett, SL;Dussault, P
采用超声促进的Diels-Alder环加成反应合成了迷迭香醌（1）及其6个类似物，产率为35- 90%。类似物包括用氢（5）、甲基（6）或叔丁基（4）取代基取代碳13（C-13）处的异丙基。氢取代的类似物的产率最低，为35%，部分原因是该化合物对空气不稳定，而甲基（85%）和叔丁基（90%）类似物的产率最高。C-14甲基类似物（7;无C-13异丙基）获得的60%产率可能是由间位取代的儿茶酚抑制环加成引起的。最后两种类似物是A环修饰，并且包括去除一个C-4甲基（3; 80%产率）或两个C-4甲基（2; 85%产率）基团。类似物进行了测试，对迷迭香醌在光敏化氧化的剥离大豆油。类似物5和6是显著（P < 0.05）优于迷迭香醌和所有其它类似物的抗氧化剂。化合物2-7的抗氧化活性没有显著差异（P < 0.05），而化合物2和4的抗氧化活性显著低于迷迭香醌（P < 0.05）。这项研究证明了抗氧化剂的结构特征的重要性，以及天然抗氧化剂，如迷迭香醌，可以通过化学修饰来改善。
Rosmariquinone (1) and six analogues were chemically synthesized using an ultrasound-promoted Diels-Alder cycloaddition in yields of 35-90%. The analogues included substitution of the isopropyl at carbon 13 (C-13) with a hydrogen (5), methyl (6), or tert-butyl (4) substituent. The hydrogen-substituted analogue had the lowest yield at 35%, due in part to the instability of the compound to air, while the highest yields were achieved for the methyl (85%) and tert-butyl (90%) analogues. The 60% yield obtained for the C-14 methyl analogue (7; no C-13 isopropyl) may have been caused by the meta-substituted catechol inhibiting the cycloaddition. The final two analogues were ring A modifications and included the removal of one C-4 methyl (3; 80% yield) or both C-4 methyl (2; 85% yield) groups. The analogues were tested against rosmariquinone in light-sensitized oxidation of stripped soybean oil. Analogues 5 and 6 were significantly (P < 0.05) better antioxidants than rosmariquinone and all other analogues. The antioxidant properties of compounds 2-7 were not significantly different (P < 0.05) from each other while compounds 2 and 4 had significantly (P < 0.05) lower antioxidant activity than rosmariquinone. This study demonstrated the importance of structural characteristics of antioxidants and that natural antioxidants, such as rosmariquinone, can be improved through chemical modification.