Ziosi Paolo, Paolucci Claudio, Santarelli Francesco, Tabanelli Tommaso, Passeri Sauro, Cavani Fabrizio, Righi Paolo
Dipartimento di Chimica Industriale "Toso Montanari", Alma Mater Studiorum-Università di Bologna, Viale del Risorgimento 4, 40136, Bologna, Italy.
Consorzio INSTM, Research Unit of Bologna, Via G. Giusti 9, 50121, Firenze, Italy.
ChemSusChem. 2018 Jul 11;11(13):2202-2210. doi: 10.1002/cssc.201800684. Epub 2018 Jun 11.
A new process for the synthesis of hydroxytyrosol (3,4-dihydroxyphenylethanol), the most powerful natural antioxidant currently known, by means of a two-step approach is reported. Catechol is first reacted with 2,2-dimethoxyacetaldehyde in basic aqueous medium to produce the corresponding mandelic derivative with >90 % conversion of the limiting reactant and about 70 % selectivity to the desired para-hydroxyalkylated compound. Thereafter, the intermediate is hydrogenated to hydroxytyrosol by using a Pd/C catalyst, with total conversion of the mandelic derivative and 68 % selectivity. This two-step process is the first example of a synthetic pathway for hydroxytyrosol that does not involve the use of halogenated components or reduction methodologies that produce stoichiometric waste. It also avoids the complex procedure currently used for hydroxytyrosol purification when it is extracted from wastewater of olive oil production.
报道了一种通过两步法合成羟基酪醇（3,4-二羟基苯乙醇）的新工艺，羟基酪醇是目前已知最强效的天然抗氧化剂。首先使儿茶酚与2,2-二甲氧基乙醛在碱性水介质中反应，生成相应的扁桃酸衍生物，限制反应物的转化率>90%，对所需对羟基烷基化化合物的选择性约为70%。此后，使用钯/碳催化剂将中间体氢化为羟基酪醇，扁桃酸衍生物完全转化，选择性为68%。这个两步法工艺是羟基酪醇合成途径的首个实例，该途径不涉及使用卤化成分或产生化学计量废物的还原方法。它还避免了从橄榄油生产废水中提取羟基酪醇时目前使用的复杂纯化程序。
