侧链带有L-氨基酸乙酯的螺旋聚苯乙炔衍生物的手性识别能力研究

CHIRAL RECOGNITION OF HELICAL POLY (PHENYLACETYLENE) DERIVATIVES BEARING L-AMINO ACID ETHYL ESTER PENDANTS

采用Rh(nbd)BPh4催化剂合成了3种侧链带有L-氨基酸乙酯的螺旋聚苯乙炔衍生物PPA-S-Phe、PPA-S-Leu和PPA-A-Leu,并将其涂覆在氨丙基硅胶上制备高效液相色谱(HPLC)手性固定相(CSP),研究其对7种对映体的手性识别能力.由于侧链手性基团或主链与手性基团之间的链接基团不同,PPA-S-Phe、PPA-S-Leu和PPA-A-Leu形成了不同的螺旋构象,并表现出对对映体不同的手性识别能力.PPA-S-Phe和PPA-S-Leu的主链与手性基团之间的链接基团均为磺酰胺基,侧链手性基团为L-亮氨酸乙酯的PPA-S-Leu的手性识别能力优于侧链手性基团为L-苯丙氨酸乙酯的PPA-S-Phe.PPA-S-Leu和PPA-A-Leu的侧链手性基团均为L-亮氨酸乙酯,以酰胺基为链接基团的PPA-A-Leu的手性识别能力明显优于以磺酰胺基为链接基团的PPA-S-Leu.螺旋聚苯乙炔主链与侧链手性基团之间的链接基团、侧链手性基团在手性识别中均发挥十分着重要作用.

Three one-handed helical poly （phenylacetylene） derivatives bearing L-amino acid ethyl ester pendants,PPA-S-Phe,PPA-S-Leu and PPA-A-Leu were respectively synthesized by the polymerization of the corresponding monomers using Rh （nbd） BPh4 as a catalyst, and their chiral recognition abilities for seven racemates were evaluated as chiral stationary phases （CSPs） for high-performance liquid chromatography （HPLC） after coating them on silica gel. The difference between PPA-S-Phe and PPA-S-Leu is the chiral pendants. The chiral pendant of PPA-S-Phe is L-phenylalanine ethyl ester, while that of PPA-S-Leu is L- leucine ethyl ester. The difference between PPA-S-Leu and PPA-A-Leu is the linkage groups between polymer main chains and chiral pendants. The linkage of PPA-S-Leu is sulphonamide group, while that of PPA-A-Leu is amide group. PPA-S-Phe, PPA-S-Leu and PPA-A-Leu possess their characteristic helical conformation and show their characteristic chiral recognition depending on the chiral pendants and the linkage groups. When linkage is a sulphonamide group, PPA-S-Leu with L-leucine ethyl ester pendants shows higher chiral recognition abilities than PPA-S-Phe with L-phenylalanine ethyl ester pendants. When chiral pendant is L- leucine ethyl ester, PPA-A-Leu with amide linkage shows higher chiral recognition abilities than PPA-S-Leu with sulphonamide linkage. It is concluded that the linkage groups play an important role in chiral recognition as well as the chiral pendants.