Chenguang Wang,Wei Xiong,Sathyanarayana Reddy Perumalla,Jianguo Fang,Changquan Calvin Sun
Dihydromyricetin (DMY) is a natural flavanol compound isolated from a traditional Chinese medicine , Ampelopsis grossedentata . Despite that optically pure (+)DMY is desired for treating chronic pharyngitis and alcohol use disorders, only DMY racemate is commercially available due to prolonged exposure time to high temperature and the presence of metal ions during industrial extraction, which cause racemization of the homochiral (+)DMY. We have developed an extraction method for successfully obtain optically pure (+)DMY. We have further assessed the physicochemical properties of the two phases using PXRD, DSC , TGA, FTIR, and moisture sorption. Among them, PXRD and FT-IR are suitable for quickly distinguishing homochiral (+)DMY from racemic (±)DMY. Lastly, with the aid of cocrystallization with theophylline , the absolute configuration of homochiral (+)DMY was identified to be (2R, 3R).
Zhiqiang Wang,Siqi Duan,Ruiting Zhang,Lin Ma,Ke Lin
Chiral molecules play a very important role in biological systems, and more and more chiral drugs are used in the treatment of diseases. Mandelic acid (MA) is an important chiral starting substance or the key intermediate of some chiral drugs, and the rapid detection of its chiral purity is very important in the synthesis, separation and detection of drugs. In this study, we developed a method for rapid determination of chiral purity of MA by Raman spectroscopy, and measured a series of Raman spectra of different chiral MA. Through the analysis, it is found that the OH stretching vibration peak can be used to identify the components of chiral molecules, and the enantiomeric excess ( ee value) obtained is in good agreement with the real value, and the error is about 5%. The experimental detection speed is fast and the efficiency is high. Our work firstly provides a new idea for the purity detection of chiral molecules by the original Raman spectrum.