Description
New process for preparing the fluoroquinolone antibacterial drug
levofloxacin was described. The
object compound was prepared from 2,3,4,*-tetrafluorobenzoic acid,
via acyl chlorination, ethyl
N,N-dimethylaminoacrylate coupling, S-(+)**-aminopropanol
displacement, cyclization, hydrolysis, and finally
N-methylpiperazine condesation, the total yield is *2.3%. Comparing
to the old process conventionally used at
present, the application of the new starting material ethyl N,
N-dimethylaminoacrylate can curtail three reaction
steps, they are the diethyl malonate condensation, partial
hydrolysis decarboxylation and triethylorthoformate
condensation. New process has many advantages, such as simple
procedure, short reaction period, high optical
purity, cheaper raw material，higher yield. So it should have a
good prospect for industrial application.
Key words: levofloxacin; ethyl N, N-dimethylaminoacrylate;
intermediate; fluoroquinolone; synthesis
