作者:Jin Tatsuzaki、Tomohiko Ohwada、Yuko Otani、Reiko Inagi、Tsutomu Ishikawa
DOI:10.3762/bjoc.14.291
日期:——
(OH) groups of quercetin (3,5,7,3',4'-pentahydroxyflavone), the OH group at 5 position is the most resistant to methylation due to its strong intramolecular hydrogen bonding with the carbonyl group at 4 position. Thus, it is generally difficult to synthesize the pentamethyl ether efficiently by conventional methylation. Here, we describe a simple and effective per-O-methylation of quercetin with dimethyl
槲皮素(3,5,7,3',4'-五羟基黄酮)的五个羟基(OH)基团中,5位的OH基团与5位的羰基形成较强的分子内氢键,因此最能抵抗甲基化。 4位置。因此,通常难以通过常规甲基化有效地合成五甲醚。在这里,我们描述了槲皮素与硫酸二甲酯在氢氧化钾(或钠)/二甲亚砜中在室温下进行约2小时的简单有效的全O-甲基化,定量地得到槲皮素五甲醚(QPE)作为单一产物。当用碘甲烷代替硫酸二甲酯时,也形成C-甲基化产物6-甲基槲皮素五甲醚。一项计算研究为实验结果提供了理论依据。