描述了串联“核内” /“核内”方法合成的miktoarm树状-线性星形共聚物。这种合成方法是通过合理设计和合成正交保护的化合物实现的,该化合物包含六个以交替方式排列的位点,用于连接树枝状聚合物和线性聚合物链的原子转移自由基聚合。对树状聚合物表面官能度的明智选择与在线性链中使用的单体的性质相结合,可以产生能够超分子组装的两亲性分子。1个嵌段共聚物的1 H NMR和SEC研究证实,以低多分散性和高收率获得了目标聚合物结构。臂和树突的性质和大小对通过动态光散射测得的流体力学半径(R h)有重大影响。这些大分子中的一些在退火后微相分离。
Synthesis and structure of 2-aryl-5,5-disubstituted-1,3-dioxanes and conversion into chiral (1,1,1-trishydroxymethyl) methane derivatives
摘要:
Pentaerythritol, (1,1,1-trishydroxymethyl)methyl methane and ( 1, 1,1-trishydroxymethyl)nitro methane are converted into 2-aryl-5.5-bis(hydroxymethyl), 2-aryl-5-hydroxymethyl-5-methyl- or 2-aryl-5-hydroxymethyl-5-nitro-1,3-dioxanes and a range of derivatives. X-Ray and NMR analysis establishes that the latter is obtained as a single diastereomer whose structure is unambiguously determined. These materials can be elaborated to chiral derivatives of the starting (1.1.1-trishydroxymethyl) methanes. (C) 2002 Elsevier Science Ltd. All rights reserved.