A PREPARATION METHOD OF HIGH-PURITY L-CARNITINE

摘要

The present invention relate to a preparation method of high-purity L-carnitine which belongs to an important technique of qulity control in different steps of chiral medicine production. The method comprises the following steps of :monitoring the content of the L-isomer impurity in chiral material S-epichlorohydrin by gas chromatography and chiral cilumn and controlling the content of the L-isomer impurity in chiral raw material in the definite range; monitoring and controlling the specific optical rotation of the chiral intermediate L-3-chloro-2-hydroxy-N,N,N-trimethyl-propanaminium in the definite ranges using a polarimeter; monitoring the content of the R-isomer in the intermediate L-3-cyano-2-hydroxy-N,N,N-trimethyl-propanaminium using derivation agent (+)±-methyl-6-methoxy-2-naphthaleneaceyl chloride by HPLC and controlling the content of the isomer in the intermediate in the definite range; and measuring the final product L-carnitine using derviation agent (+)±-methyl-6-methoxy-2-naphthaleneaceyl chloride by HPLC. This method gives the high-purity L-carnitine in which the content of L-isomer may be more than 97% and that of R-isomer less than 2%.