Synthesis And Applications Of Poly(ethylene Glycol) Derivatives

Poly(ethylene glycol) (PEG) is applied to organic synthesis as soluble support, which combines the superiorities of solid phase synthesis such as easy separation and purification, recyclable usage, convenient reprocessing and advantages of classical homogeneous reaction such as detecting reactive procedure with routine analytic methods.In this paper, using PEG as soluble polymer support we synthesized two kinds of PEG-supported dendrimers, and applied them to modify decellularized leaflets; using PEG as soluble polymer support we synthesized PEG-supported pyridine ylide, and applied it to prepare polysubstituted cyclopropanes derivatives.The first section:synthesis and application of PEG-supported dendrimers.This section summarized the research progress of PEG-supported dendrimers and their applications in biomedical in recent years. Based on the advantages of PEG-supported dendrimers modifing drugs, peptides and previous work of our laboratory, presented the design idea. Using PEG with different molecular weight as starting materials, dimethyl 5-hydroxyisophthalate as linker, we synthesized two new kinds of dendrimers PEG-DA4 and PEG-NHS4 with acroloyl and NHS as active group respectively, and applied them to modify decellularized leaflets. Optimized the modification conditions, and obtained the best condition; investigated the modification effect of decellularized leaflets modified by different molecular weight of PEG-DA4, with the static tensile test, we reached a decision that PEG20000-DA4 is the best modification agent; investigated the modification effect of decellularized leaflets modified by two kinds of dendrimers PEG-DA4 and PEG-NHS4, with the test of tensile strength, we draw a conclusion that PEG-DA4 is better than PEG-NHS4.The second section:synthesis and application of PEG-supported pyridine ylide.This section summarized the applications of PEG-supported pyridine ylide in organic synthesis. Based on the previous work of our laboratory, the synthetical route was presented. PEG-supported acetyl bromide as starting material, reacted with pyridine and obtained PEG-supported pyridine ylide. Then it was treated with olefins generated by Knoevenagel condensation of malononitrile or ethyl cyano group and aromatic aldehydes, and obtained 14 polysubstituted cyclopropanes derivatives. The structure of these compounds was characterized and confirmed by'HNMR,13CNMR, IR. Also these compounds were all trans-configuration, which were confirmed by'HNMR.PEG acted polymer support and protective group in the whole reaction, and tran-configuration was the only reaction products because of huge steric hindrance of PEG. Compared with classic liquid-phase synthesis, product yield increased greatly, so PEG also played the role of phase transfer catalyst, improving the reaction rate.