- Chemoenzymatic Asymmetric Synthesis of 1,4-Benzoxazine Derivatives: Application in the Synthesis of a Levofloxacin Precursor
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A versatile and general route has been developed for the asymmetric synthesis of a wide family of 3-methyl-3,4-dihydro-2H-benzo[b][1,4]oxazines bearing different pattern substitutions in the aromatic ring. Whereas hydrolases were not suitable for resoluti
- López-Iglesias, María,Busto, Eduardo,Gotor, Vicente,Gotor-Fernández, Vicente
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p. 3815 - 3824
(2015/05/04)
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- Propoxybenzene derivatives and process for preparing the same
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Propoxybenzene derivatives represented by the following formula STR1 wherein Ra represents a nitro group, an amino group which may have a protecting group or an --NHCH=C(COO--C1-6 -Alkyl)2 group, Rb represents a hydrogen atom, a protecting group for the hydroxyl group or a substituted sulfonyl group and Xa and Xb, which may be the same or different, each represents a halogen atom, and processes for preparation thereof are disclosed. These derivatives are useful in preparing antibacterial agents.
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- Optically active benzoxazines and bezothiazines and a process for their stereospecific preparation
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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.
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