Study On Hvdrolase-catalyzed Polymerization And Synthesis And Mechanism Of Spirocompounds

Enzymology has gained more and more attention because of their advantages such as mild reaction conditions,high selectivity and pollution-free.As one of the most widely used biocatalysts in organic chemistry,hydrolase has been used to catalyze both the polymerization for macromolecular organic materials and some promiscuous reactions such as michael addition,aldol reaction,markovnikov reaction and some one-pot domino reactions.Therefore,the study of hydrolase-catalyzed promiscuous reactions is attractive to synthetic chemists in academia and industry,and also to biotechnologists.A protease-catalyzed synthesis method for alternating peptides similar to antifreeze protein was developed.Based on the structural feature of APF types I and AFGP,we used protease as catalyst to synthesize alternating peptide which contained repeating Ala-Ala-Thr unit in organic solvent for the first time.Three different sequence of antifreeze peptide PAAT,PATA and PTAA were obtained under the optimal condition,respectively.The chemical structures and molecular weight were characterized by NMR spectra and mass spectra.Thermal properties were determined by TGA and DSC while the antifreezing ability of obtained peptides was evaluated through differential scanning calorimetry(DSC).A lipase-catalyzed synthesis method for alternating chiral poly(ester amide)was studied.L-or D-aspartate was incorporated to endowed this kind of biodegradable poly(ester amide)s with chirality and function groups.Eight alternating poly(ester amide)s were synthesized as promising biomedical materials under the optimum reaction conditions.Thermal properties as well as the aggregate microstructure of obtained poly(ester amide)s were investigated.What is more,four kinds of chiral poly(ester amide)s with pendant ?-or p-carboxylic groups were combined with Rh3+ and Ru3+ to obtain eight metal complexes and a series properties of these poly(ester amide)s and metal complexes were investigated.Two simple and environmentally friendly methods to synthesize spirooxindole derivatives starting from isatin were developed.With the optimized conditions for enzymes,solvents,enzyme loading and reaction time in hand,two kinds of compounds were obtained in acceptable yields.Moreover,a chemo-enzymatic two-step process was also designed to improve the yields of DA-catalyzed reaction successfully and several representative spirooxindole derivatives could be obtained in nearly quantitative yields.The investigation in fluorescent properties of papain-catalyzed spirooxindoles showed their potential application in the field of new fluorescent material.What is more,the zinc ions in the active site of D-aminoacylase were replaced by other mental ions to study enzyme reconstruction.Temperature and time in this process were optimized to get the best results.At last,the catalytic activity and metal content of these mental-DA enzymes were investigated.