Feng Xiaoshuang, Taton Daniel, Chaikof Elliot L, Gnanou Yves
Laboratoire de Chimie des Polymères Organiques, Université Bordeaux-1-CNRS-ENSCPB, 16, Avenue Pey-Berland, 33607 Pessac Cedex, France.
Biomacromolecules. 2007 Aug;8(8):2374-8. doi: 10.1021/bm070146r. Epub 2007 Jul 13.
Doubly functionalized dendrimerlike poly(ethylene oxide)s (PEOs) carrying 16 hydroxyl groups at their periphery and one aldehyde group at their focal point were synthesized up to the fourth generation through an iterative divergent approach. First, a protected aldehyde dihydroxyl compound, namely, 3,3-diethoxy-1,2-propanediol, was used as initiator for the anionic ring-opening polymerization (AROP) of ethylene oxide after partial deprotonation (30%) in dimethyl sulfoxide. The two hydroxyls carried by the PEO chain ends of the first generation were subsequently derivatized so as to generate four hydroxyls via a two-step reaction (allylation and osmylation). The next generations of such dendrimerlike PEOs were grown upon repeating the same cycle of AROP and chain-end modification. At the completion of these reactions, the acetal group present at the core was deprotected under acidic conditions to afford the targeted dendrimerlike PEO of fourth generation with a central aldehyde group. The reactivity and accessibility of the latter function was demonstrated upon its conjugation with aniline used as a model compound.
通过迭代发散法合成了在其外围带有16个羟基且在其焦点处带有一个醛基的双功能树枝状聚环氧乙烷（PEO），直至第四代。首先，将一种受保护的醛二羟基化合物，即3,3 - 二乙氧基 - 1,2 - 丙二醇，在二甲基亚砜中部分去质子化（30%）后用作环氧乙烷阴离子开环聚合（AROP）的引发剂。第一代PEO链端携带的两个羟基随后通过两步反应（烯丙基化和锇化）进行衍生化，从而生成四个羟基。重复相同的AROP和链端修饰循环来生长此类树枝状PEO的下一代。在这些反应完成后，核心处存在的缩醛基团在酸性条件下脱保护，得到具有中心醛基的目标第四代树枝状PEO。后者官能团与用作模型化合物的苯胺共轭时，证明了其反应性和可及性。
