Abstract

The O–H bond strength was calculated by the G4 and the M06-2X/MG3S methods for 2‑hydroxy-3-methylcyclopent-2-en-1-one (maple lactone), 4-hydroxy-2,3-dimethyl-2H-furan-5-one (sotolon), 4-hydroxy-5-methylfuran-3-one, 4-hydroxy-2,5-dimethylfuran-3-one (strawberry furanone), (2R)-2-[(1S)-1,2-dihydroxyethyl]-3,4-dihydroxy-2H-furan-5-one (ascorbic acid), 5-hydroxy-2-(hydroxymethyl)pyran-4-one (kojic acid), 3-hydroxy-2-methylpyran-4-one (maltol), 3-hydroxy-2-ethylpyran-4-one (ethylmaltol), 4-hydroxy-6-methylpyran-2-one, and 5-hydroxy-6-methyl-3,4-dihydro-2H-pyran-4-one (dihydromaltol). The calculations indicated the presence of a weak O–H bond of less than 82.0 kcal/mol in 4-hydroxyfuran-3-one derivatives. The experimental rate constant of the reaction of the compound with the lowest O–H bond strength, 4-hydroxy-2,5-dimethylfuran-3-one, with peroxyl radicals in chlorobenzene and acetonitrile was comparable to the data for dibutylhydroxytoluene, but the stoichiometric coefficient of inhibition was 0.17 (PhCl) and 0.66 (MeCN), which was significantly smaller than for dibutylhydroxytoluene. The activation enthalpy for hydrogen atom elimination from 4-hydroxy-2,5-dimethylfuran-3-one by peroxyl radicals calculated by the SMD(PhCl)-M05/MG3S method correlated well with the data for 5-hydroxy and 5-aminouracil derivatives, which is indicative of the common mechanism of interaction of these compounds with peroxyl radicals.

中文翻译：

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4-羟基-2,5-二甲基呋喃-3-酮对苯乙烯自由基链氧化的抑制作用

摘要

O-H键强度通过G4和M06-2X / MG3S方法计算出2-羟基-3-甲基环戊-2-烯-1-酮（枫酸内酯），4-羟基-2,3-二甲基- 2 H-呋喃-5-酮（sotolon），4-羟基-5-甲基呋喃-3-酮，4-羟基-2,5-二甲基呋喃-3-酮（草莓呋喃酮），（2R）-2-[（ 1S）-1,2-二羟基乙基] -3,4-二羟基-2 H-呋喃-5-酮（抗坏血酸），5-羟基-2-（羟甲基）吡喃-4-酮（曲酸），3-羟基-2-甲基吡喃-4-酮（麦芽酚），3-羟基-2-乙基吡喃-4-酮（乙基麦芽酚），4-羟基-6-甲基吡喃-2-酮和5-羟基-6-甲基-3 ，4-二氢-2 H-吡喃-4-酮（二氢麦芽酚）。计算表明，在4-羟基呋喃-3-酮衍生物中，存在一个小于82.0 kcal / mol的弱OH键。具有最低OH键强度的化合物4-羟基-2,5-二甲基呋喃-3-酮与过氧自由基在氯苯和乙腈中反应的实验速率常数与二丁基羟基甲苯的数据相当，但是抑制的化学计量比为0.17（PhCl）和0.66（MeCN），显着小于二丁基羟基甲苯。通过SMD（PhCl）-M05 / MG3S方法计算出的过氧自由基从4-羟基-2,5-二甲基呋喃-3-酮中消除氢原子的活化焓与5-羟基和5-氨基尿嘧啶衍生物的数据具有很好的相关性，