A reductive decarboxylation of 7-chloro-1-ethyl-6-fluoro-1,4-dihydro-4-oxoquinoline-3-carboxylic acid (Id) with sodium borohydride provided the respective 1,2,3,4-tetrahydro derivative Va, which was treated with selenium dioxide to give product of dehydrogenation VIa. 3-Acetyl-1-ethyl-1,4-dihydroquinolin-4-ones VIb and VIc were oxidized with 3-chloroperoxybenzoic acid to the respective 3-hydroxyderivatives IIIa and IIIb. Compound IIIb was benzylated on a hydroxy group at position 3 to corresponding 3-benzyloxy derivative VIf which after prolonged heating with N-methylpiperazine in a sealed tube provided directly 3-hydroxy-7-(4-methyl-1-piperazinyl) derivative IIIc.
使用氢化钠还原7-氯-1-乙基-6-氟-1,4-二氢-4-氧喹啉-3-羧酸(Id)得到相应的1,2,3,4-四氢衍生物Va,再用二氧化硒处理得到脱氢产物VIa。3-乙酰基-1-乙基-1,4-二氢喹啉-4-酮(VIb和VIc)经过3-氯过氧苯甲酸氧化得到相应的3-羟基衍生物IIIa和IIIb。化合物IIIb在3位羟基上被苄基化为相应的3-苄氧衍生物VIf,经过与N-甲基哌嗪在密闭管中长时间加热后直接得到3-羟基-7-(4-甲基-1-哌嗪基)衍生物IIIc。