苯并呋喃酮衍生物结构对其DPPH捕获能力的影响

摘要

采用自由基比色法考察苯并呋喃酮衍生物结构对其DPPH捕获能力的影响. 结果发现,母体苯环5,7位上甲基和叔丁基的改变以及取代苯环上强供电子取代基的存在对苯并呋喃酮衍生物的DPPH捕获能力没有明显影响. 苯环2′位存在明显的位阻作用,对苯并呋喃酮衍生物的DPPH捕获能力具有明显的抑制作用;并且当此位为不含活泼氢的氢键受体取代基时,苯并呋喃酮衍生物的DPPH捕获能力会由于取代基与3位活泼氢的氢键作用而被进一步削弱;但此位为含有活泼氢的氢键受体取代基时,此取代基的氢将会由于3位活泼氢与取代基的氢键作用而活化,从而使其位阻作用得到一定程度的抑制.%The structural effect of benzofuranone derivatives on their ability to scavenge 2,2-diphenyl-1-picrylhydrazl(DPPH) was studied via radical colorimetry. The results show that the changes of methyl and tert-butyl groups on 5 and 7 positions of mother benzene ring of benzofuranone and the presence of strong electron-donating substituent in substituted benzene ring have little influences on the ability of benzofuranone derivatives scavenging DPPH. Substituent of 2′-position prevents the attack of benzofuranone toward radicals, which weak the scavenging ability of benzofuranone derivatives for DPPH. And the scavenging ability of benzofuranone for DPPH will be weakened further when the substituent of 2′-position is without reactive hydrogen and can form hydrogen bonds with 3-reactive hydrogen. When the substituent of 2′-position is with reactive hydrogen, the reactive hydrogen will be activated due to the formation of hydrogen bonding between substituted group with 3-reactive hydrogen, and the position hindrance will be generated in a great extent.