羟基酪醇快速硝基化及产物波谱表征

摘要

[Objective] Hydroxytyrosol (HT),belongs to polyphenolic compounds,was widely distributed in olive fruit.Its nitration process is very important for the field of forest products processing industry.Since the traditional method with mixture of concentrated sulfuric acid and nitric acid was easy to make phenolic compound oxidation,and is not an environmentally friendly process.It is thus imperative to find a new fast way to make it nitration,unveiling the product chemical structure by classic multiple spectroscopies in the meantime.[Method] By means of being mixed with NaNO2 under the condition of weak acid and room temperature,hydroxytyrosol was nitrated quickly.The nitro product was characterized by Uv-vis,FTIR,HPLC-MS,1HNMR and 13CNMR.[Result] It was observed that this reaction can be finished in 10 min with pH 3.8 (HAC-NaAC butter solution),achieving yield conversion 99.5％.Also,the maximum adsorption wavelengths of nitro-hydroxytyrosol were 245,296 and 346 nm by Uv-vis spectrophotometer.Phenolic hydroxyl (wavenumber 3 359 cm-1) of hydroxytyrosol as a reactant in the reaction process did not change,and nitro group (wavenumber 1 557 and 1 405 cm-1) was introduced into hydroxytyrosol by the results of FTIR.The chemical structure of reaction product was further confirmed by HPLC-MS,1HNMR and 13CNMR,giving rise to a MW 199 and nitro group linked into para-position of phenolic hydroxyl in hydroxytyrosol.[Conclusion] By means of mild operation conditions (room temperature,pH 3.8 and 10 min),mixing with NaNO2 as a cheap and accessible industrial raw material,hydroxytyrosol is very easy to get nitrated quickly and the nitro group in the product single-located in para-position of phenolic hydroxyl.These will provide a new path for nitro-phenol preparation to replace a traditional method using mixed strong acids,being of an importance.%[目的]为解决传统硝基化方法存在的易使羟基酪醇氧化和反应过程污染大等问题,建立一种对羟基酪醇进行快速硝基化反应的新方法,并解析反应产物结构,为邻二苯酚类化合物的硝基化及产物鉴定提供理论和数据支持.[方法]构建弱酸和室温环境,将亚硝酸钠与羟基酪醇充分混合进行快速硝基化反应,运用Uv-vis、FTIR、HPLC-MS、1HNMR和13CNMR等手段表征其硝基化产物.[结果]在室温和HAC-NaAC缓冲液(pH 3.8)条件下反应10 min,硝基羟基酪醇的转化率达99.5％;Uv-vis全波段扫描结果表明,硝基羟基酪醇的最大吸收波长分别为245、296和346 nm;FTIR结果表明,反应物羟基酪醇中的酚羟基在反应过程中未发生变化(波数3 359 cm-1),而其反应产物中引入了硝基基团(波数1 557和1 405 cm-1);反应产物的HPLC-MS结果证实硝基羟基酪醇的相对分子质量为199,1HNMR和13CNMR结果证实了硝基基团键合于羟基酪醇酚羟基的对位.[结论]以温和的反应条件(室温、pH3.8和10 min),使用价廉易得的亚硝酸钠调控羟基酪醇快速硝基化,及形成专一性对位取代产物的特征,使其在替代传统混合强酸制备硝基酚方面具有重要意义.