Optically active 7,8-difluoro-3,4-dihydro-3-methyl-2H-[1,4]benzoxazines and 7,8-difluoro-3,4-dihydro-2-methyl-2H-[1,4]benzoxazines and the corresponding benzothiazines of formula III,
where, one of the substituents R1, R2, R3 and R4 is CH20H or -CH2Z, the remaining being hydrogen, X denotes fluoro, chloro, methyl or hydrogen, Y is oxygen or sulfur and Z is hydrogen, fluoro or protected hydroxyl are obtained as the stereochemically pure products of a stereospecific synthesis using a 3,4-difluoronitrobenzene substituted with a stereochemically pure 2-(1-hydroxyisopropoxy), 2-(2-hydrox-I ypropoxy), 2-(1-hydroxyisopropylthio) or 2-(2-hydroxypropylthio) substituent.The obtained compounds are suited for the production of optically active pyridobenzoxazines and pyridobenzothiazines, among which are useful antibacterial optically active quinolones, particularly (S)-(-)-ofloxacin.
具有光学活性的7,8-二
氟-3,4-二氢-3-甲基-2H-[1,4]苯并噁嗪和7,8-二
氟-3,4-二氢-2-甲基-2H-[1,4]苯并噁嗪以及相应的式III的苯并
噻嗪,其中R1、R2、R3和R4中的一个取代基是CH20H或-CH2Z,其余为氢,X代表
氟、
氯、甲基或氢,Y为氧或
硫,Z为氢、
氟或受保护的羟基,作为立体
化学纯产品通过使用具有立体
化学纯2-(1-羟基异丙氧基)、2-(2-羟基异丙氧基)、2-(1-羟基异丙基
硫基)或2-(2-羟基
丙硫基)取代基的
3,4-二氟硝基苯进行立体特异性合成而获得。所得化合物适用于生产光学活性的
吡啶苯并噁嗪和
吡啶苯并
噻嗪,其中包括有用的抗菌光学活性
喹诺酮,特别是(S)-(-)-
氧氟沙星。