以苯甘氨酸基为侧链的光学活性甲基丙烯酰胺共聚物的合成及特性

Synthesis and Properties of Optically Active Methacrylamide Copolymers with Side Chains

利用酰胺化反应合成带有2个手性中心的手性烯类单体N-(R)-((N-(R)-1-苯乙酰胺)-苯基)甲基丙烯酰胺(RRPEABMAM)。以偶氮二异丁腈(AIBN)为引发剂。通过自由基聚合法,将手性单体RR-PEABMAM与甲基丙烯酸甲酯(MMA)在不同的溶剂中反应24 h,得到具有不同性质的共聚物。利用红外光谱、凝胶渗透色谱、旋光仪和差示扫描量热分析对共聚物的性质进行了分析。随着手性单体组分的不断增加,共聚物与其光学活性完全相反,这表明共聚物的主链形成了一定的二级结构。另外,共聚物组分和聚合溶剂都对共聚物的性质有较大的影响。在甲苯中形成的共聚物与在甲醇中得到共聚物的性质有所不同,说明分子间氢键在共聚物的形成过程中起了一定的作用。以共聚物5制备了一种涂敷型高效液相色谱用手性固定相(CSP),对部分对映体具有一定的手性识别能力。

A chiral vinyl monomer N-{( R)-[( R)-1-phenylethylaminocarbonyl]benzyl } methacrylamide( RRPEABMAM) containing two chiral centers was synthesized via amidation reaction. Optically active copolymers were prepared via free radical polymerization of RR-PEABMAM with MMA initiated by azo-bis-isobutryonitrile( AIBN) at 60 ℃.IR,GPC,polarimeter and DSC were employed to characterize properties of the products. A remarkable change in optical activity is observed during transformation from monomers to the corresponding copolymers. The opposite sign of copolymers compared to the chiral monomer from which it is formed indicates a chiral secondary structure of the copolymer main chain. On the other hand,the composition of monomers has great effects on the properties of copolymers. Due to formations of hydrogen bonds of monomer RR-PEABMAM with methanol,the copolymer prepared in toluene displays a great difference in chiroptical properties compared with the one prepared in methanol,indicating that hydrogen bonds play an important role in properties of the copolymers. Copolymer 5 is coated onto silica gel as the chiral stationary phase( CSP) for high performance liquid chromatography( HPLC). The CSP exhibits a superior chiral recognition ability for some racemates.