Progress of Synthesis α-Substituted Propanoic Acids Drugs by Transition Metal-catalyzed Asymmetric Hydrogenation / 现代生物医学进展

Optically pure α-substituted propanoic acids and their derivatives represent as an important kind of organic building blocks and key intermediates,which has been widely used in the synthesis of chiral drugs.Some of them have been used directly as nonsteroidal anti-inflammatory drugs (NSAIDs),such as ibuprofen,naproxen,ketoprofen and so on.Dihydroartemisinic acid (DHAA),the same structure as the α-substituted propanic acids,is a key intermediate for the synthesis of artemisinin,the most effective and current used anti-malarial drug.Therefore,the asymmetric synthesis of α-substituted propanoic acids is always a hot topic for chemical scientists.Asymmetric catalytic hydrogenation attracts more and more attentions because of its atom economy and efficiency.This dissertation will disclose the asymmetric synthesis of α-substituted propanoic acids using transition metal-complex as a chiral catalyst.

Electronic circular dichroism behavior of chiral Phthiobuzone

Phthiobuzone is a bis(thiosemicarbazone) derivative with a single chiral center which has been used as a racemate in the clinical treatment of herpes and trachoma diseases. In this study, its two enantiomers were prepared from chiral amino acids and their absolute configurations were investigated by electronic circular dichroism (ECD) combined with modern quantum-chemical calculations using time-dependent density functional theory. It was found that solvation changed both the conformational distribution and the ECD spectrum of each conformer. The theoretical ECD spectra of the two enantiomers were in good agreement with the experimentally determined spectra of the corresponding isomers in dimethyl sulfoxide. The ECD behavior of the bis(thiosemicarbazone) chromophore in a chiral environment is also discussed. Our results indicate that ECD spectroscopy may be a useful tool for the stereochemical evaluation of chiral drugs.