在含有1%甲醇的0.05 M醋酸盐缓冲液(pH 4)中,咖啡酸(1a)(2 x 10(-3)M)与亚硝酸盐(NO(2)(-))(4 x 10(-3)平稳反应M)作为主要产品提供较小的新型2-羟基-和2-甲氧基醛肟7a,b,2-环氧醛肟9a,3,4-二羟基苯甲酸,3,4-二羟基苯甲醛和已知的呋喃喃3c和苯并恶嗪酮4b金额。在较低的1a浓度下(例如1 x 10(-4)M),主要产物为7a,而0.1 m 1a和0.5 M NO(2)(-)3c和9a为主要产物。在pH 2时,7a与3,4-二羟基苯甲醛和一些9a仍然是最丰富的产物,而在pH 1时,9a和3,4-二羟基苯甲醛的产率更高。没有获得关于环硝化产物的证据,包括先前报道的4,5-二羟基-2-硝基苯甲醛。在2 x 10(-3)M浓度和pH 4下 咖啡酸甲酯(1b)主要通过环硝化和/或二聚反应与NO(2)(-)反应生成5a,新型硝化的新木脂素衍生
Reaction of caffeic acid derivatives with acidic nitrite
作者:Philippe Cotelle、Hervé Vezin
DOI:10.1016/s0040-4039(01)00441-5
日期:2001.5
Caffeic derivatives were reacted with acidic nitrite at controlled pH in order to mimic the gastric juice conditions. At pH 2, whereas caffeic acid reacts exclusively on the side chain, its esters are readily nitrated. Under more acidic conditions (pH 1), caffeic acid methyl ester undergoes a dimerisation into a norlignan derivative. (C) 2001 Published by Elsevier Science Ltd.