[EN] METHOD FOR THE PREPARATION OF PROCESS INTERMEDIATES FOR THE SYNTHESIS OF ARGATROBAN MONOHYDRATE [FR] PROCÉDÉ DE PRÉPARATION D'INTERMÉDIAIRES DE PROCÉDÉ POUR LA SYNTHÈSE DE L'ARGATROBAN MONOHYDRATE
The Role of Diastereomer Impurity in Oiling-Out during the Resolution of <i>trans</i>-4-Methyl-2-piperidine Carboxylic Ethyl Ester Enantiomers by Crystallization
作者:Riju Ren、Dengqiong Sun、Tingting Wei、Shixin Zhang、Junbo Gong
DOI:10.1021/op500026z
日期:2014.6.20
Isolating enantiomers by crystallization via diastereomer salt formation is widely used in the pharmaceutical industry. Unfortunately, we found that, when some diastereomer impurity exists, oiling-out will take place and significantly decrease the resolution efficiency. To identify the role of impurities in oiling-out, three series of chiral resolution of trans-4-methyl-2-piperidine carboxylic ethyl ester (trans-4MPE) with different levels of diastereomer impurity were performed. Using process analytical technologies (PAT) technologies, the demixing region was identified by measuring TL-L curves and supersolubility curves for different series. It was found that a series with a higher level of impurity has a higher TL-L point and a wider demixing region. Besides, it seems that the resolution efficiency through oiling-out, as well as the crystallization kinetics, was significantly decreased. Here we initially put forward this particular diastereomer purification problem, where the impurity has a positive effect on oiling-out. To reduce or eliminate oiling-out, an efficient prepurification strategy must be ensured.