(+/-)-1-(3-benzoylthio-1-oxopropyl)-1,2,3,4-tetrahydro-6-methoxy-2-quinolinecarboxylic acid 、 (+/-)-1-(2-benzoylthio-1-oxopropyl)-1,2,3,4-tetrahydro-2-quinolinecarboxylic acid 以(±)-1,2,3,4-tetrahydro-1-(3-mercapto-1-oxopropyl)-6-methoxy-2-quinolinecarboxylic acid was obtained as an oily residue的产率得到(+/-)-1,2,3,4-Tetrahydro-1-(3-mercapto-1-oxopropyl)-6-methoxy-2-quinolinecarboxylic acid