107358-77-0Relevant articles and documents
Optically active benzoxazines and bezothiazines and a process for their stereospecific preparation
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, (2008/06/13)
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 CH2OH 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--hydroxypropoxy), 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.