Studies on the 1,1-diphenyl-2-picrylhydrazyl radical scavenging mechanism for a 2-pyrone compound
Studies on the 1,1-diphenyl-2-picrylhydrazyl radical scavenging mechanism for a 2-pyrone compound
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DOI：
10.1271/bbb.64.306
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发表时间：
2000-02-01
影响因子：
1.6
通讯作者：
Hirota, A
中科院分区：
文献类型：
--
作者：
Abe, N;Nemoto, A;Hirota, A
通过270 nm波长处化合物的定量变化和高效液相分析，研究了2-吡喃酮类化合物4-羟基-3，6-二甲基-2H-吡喃-2-酮(1)和1，1-二苯基-2-苦基肼(DPPH)(4)在几种溶剂体系中的清除机理。每种条件下的高效液相图谱表明，反应在每种溶剂体系中以不同的机理进行。在有机溶剂(CHCl_3、异丙醇和乙醇)中，1-[4-(3，4-dihydro-3，6-dimethyl-2，4-dioxo-2H-pyran-3-yl)phenyl]-1-phenyl-2-picrylhydrazine(2)作为DPPh自由基和1的加合物生成。另一方面，在缓冲溶液(pH为5.5的醋酸盐缓冲液)中反应生成几种与1-[4-(2，3-dihydro-2，5-dimethyl-3-oxo-fur-2-yl)苯基]-1-苯基-2-苦基肼(5)的降解产物。这是通过光谱分析从结构上阐明的。各反应体系中DPPH自由基的减少表明，化合物1在有机溶剂中对DPPH自由基的清除当量约为1.5~1.8当量，在缓冲溶液中约为3.5~3.9当量。
The radical scavenging mechanisms for the 2-pyrone compound, 4-hydroxy-3,6-dimethy1-2H-pyrane-2-one (1), and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical (4) in several solvent systems were evaluated by the quantitative change in compounds detected at 270 nm and subsequent HPLC analyses. The HPLC profile for each condition suggested that the reaction proceeded by a different mechanism in each solvent system. In organic solvents (CHCl3, iso-propanol, and EtOH), 1-[4-(3,4-dihydro-3,6-dimethyl-2,4-dioxo-2H-pyran-3-yl)phenyl]-1-phenyl-2-picrylhydrazine (2) was produced as an adduct of the DPPH radical and 1. On the other hand, the reaction in a buffer solution (an acetate buffer at pH 5.5) gave several degradation products with 1-[4-(2,3-dihydro-2,5-dimethyl-3-oxo-fur-2-yl) phenyl]-1-phenyl-2-picrylhydrazine (5), this being structurally elucidated by spectroscopic analyses. The decrease of the DPPH radical in each reaction system suggests that compound 1 could scavenge about 1.5-1.8 equivalents of the radical in organic solvents and about 3.5-3.9 in the buffer solution.