Oxidative rearrangement of 2′-hydroxychalcones having no substituent at the 3′- and 5′-positions with thallium(<scp>III</scp>) nitrate in methanol
作者:Tokunaru Horie、Yasuhiko Kawamura、Chikako Sakai、Ayako Akita、Masahiro Sasagawa、Toshihide Yamada
DOI:10.1039/p19960001987
日期:——
Oxidation of 2′-hydroxychalcones with no substituents at the 3′-and 5′-positions with thallium(III) nitrate (TTN) in methanol has been studied in detail and the following results obtained. (1) 2′-Hydroxy-4,6′-dimethoxychalcones (1b and 2b) have increased reactivity over their methyl ethers as a result of participation of the 6′-methoxy oxygen atom; the reactivity of 2′-hydroxy-4,4′-dimethoxychalcone
al在3'和5'位置没有取代基的2'-羟基查耳酮的氧化(III)已经详细研究了甲醇中的硝酸盐(TTN),并获得了以下结果。(1)由于6'-甲氧基氧原子的参与,2'-羟基-4,6'-二甲氧基查耳酮(1b和2b)相对于它们的甲基醚具有增加的反应性;但是2'-羟基-4,4'-二甲氧基查耳酮3b的反应性降低。(2)反应受到A和B环上取代基的极大影响,并形成相应的1,2-二芳基-3,3-二甲氧基丙烷-1-酮(乙缩醛)和/或2-(α-甲氧基苄基)香豆烷酮(香豆酮):通过在4-和/或2-位上的甲氧基极大地促进了氧化重排,从而得到了作为主要产物的乙缩醛。(3)仅当2′-羟基查耳酮在6′-位具有甲氧基且具有较弱的供电子性的B环时,才观察到香豆素的形成。(4)在2'在4'-位没有取代基的反应中形成的香豆烷酮的比率低于在2'-羟基和相邻的羰基之间迅速形成环状TTN配合物的1的比率。仅2'-羟基-6'-甲氧基查耳