5-HYDROXYMETHYL-OXAZOL1DIN-2-ONE DERIVATIVES The present invention concerns novel chimeric antibiotics that are obtained from oxazolidinone derivatives linked to a quinolone or iiaphthyridinone via a spacer, pharmaceutical antibacterial compositions containing them and the use of these compounds in the manufacture of a medicament for the treatment of infections {e.g. bacterial infections). These chimeric compounds are useful antimicrobial agents effective against a variety of human and veterinary pathogens including among others Gram-positive aerobic bacteria. Gram-negative bacteria, anaerobic organisms and acid-fast organisms. The intensive use of antibiotics has exerted a selective evolutionary pressure on microorganisms to produce.genetically based resistance mechanisms. Modern medicine and socio-economic beliaviour exacerbate the problem of resistance developnienl by creating slow growth situations for pathogenic microbes, e.g. in artilicial joints, and by supporting long-term host reservoirs, e.g. in immuno-compromised patients. [n hospital settings, an increasing number of strains of Staphylococcus aiiret^s. Streptococcus pneumonia, Enterococcus spp., and Pseudomonas aeruginosa, major sources of infections, are becoming multi-drug resistant and therefore difficult if not impossible to treat: - 5". aureus is B-lactam. quinolone and now even vancomycin resistant; - S. pneiuuoniae is becoming resistant to penicillin, quinolone and even to new macrolides; - Enteroccocci are quinolone and vancomycin resistant and 13-lactams were never efficacious against these strains. ![ Further new emerging organisms like Acinetohacter spp. or C. difficile, which have been selected during therapy with the currently used antibiotics, are becoming a real problem in hospital settings. In addition, microorganisms that are causing persistent infections are increasingly being recognized as causative agents or cofactors of severe chronic diseases like peptic ulcers or heart diseases. In a chimeric molecule two or more molecules that exist separately in their native state are joined together to form a single entity (i.e. molecule) having the desired functionality of all of its constituent moleculds: Molecules wherein two antibiotics that have two different modes of action have been linked have been reported in the literature (e.g. Journal of Anlimicrohia! Chemotherapy (1994), 33, 197-200). Many of them are however such that the two antibiotic parts are released after biological activation {e.g. central ester cleavage, beta-lactam cleavage). Chemically and biochemically stable chimeric molecules that bind, as such, in two different targets have been more seldom reported. For example, oxazolidinone-quinolone hybrids have been reported as useful antimicrobial agents effective against a variety of multi-drug resistant pathogens (WO 03/032962, WO 03/031443 and WO 2004/096221, WO 2005/023801 and WO 2005/058888). Further, synthesis and biological evaluation of these hybrids {Bioorg. & Med. Chew. (2003), 11, 2313-2319) and the influence of the central spacer on the antibacterial activity in the structure-activity relationship in the oxazolidinone-quinolone series have also been reported {Bioorg. Med Chem. Lett. (2003), 13, 4229-4233). All these derivatives contain a 4-aminomethyl-oxazolidinone rest as part of the oxazolidinone pharmacophore. It has now been surprisingly found that the chimeric derivatives of formula 1 as defined hereafter are particularly effective antimicrobial agents that show effective against a variety of multi-drug resistant bacteria. Thus, the present invention relates to compounds of formula I O F R* wherein R' represents OH, OPO3H2 or OCOR^ R^ represents H, OH or OPO3I-I2; A represents N or CR"; R represents H or fluorine: R" is H, (C1-C3) alkyl or cycloalkyl; R^ is the residue of a naturally occurring amino acid, of the enantiomer of a naturally occurring amino acid or of dimethylaminoglycine; R represents M, alkoxy or halogen; and n is 0 or I; and to salts (in particular pharmaceutically acceptable salts) of compounds of formula I. The compounds of formula I may contain one or more stereogenic or asymmetric centers, such as one or more asymmetric carbon atoms. The compounds of formula I may thus be present as mixtures of stereoisomers or preferably as pure stereoisomers. Mixtures of stereoisomers may be separated in a manner known to a person skilled in the art. The following paragraphs provide definitions of the various chemical moieties for the compounds according to the invention and are intended to apply uniformly throughout the specification and claims unless an otherwise expressly set out definition provides a broader or narrower definition. ■■ '; 1' '^ Unless specified otherwise, the term "alkyl".|(whether used alone or in combination) refers to a saturated straight or branched chain alkyl group containing I to 6 carbon atoms, and preferably i lo 3 carbon atoms. Representative examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, wo-propyl, butyl, /.vobutyl. .sx'c-butyl. ler!-buiy\, n-pentyl, neopentyl, /.vo-pentyl, w-hexyl and /.vo-hexyl. The term "(Ci-Cx)alkyl" (x being an integer) refers to a saturated straight or branched chain alkyl group containing I to x carbon atoms. The term "alkoxy" refers to a saturated straight or branched chain alkoxy group, containing 1 lo 6 carbon atoms, and preferably I to 3 carbon atoms. Representative examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy. /50-propoxy, /7-butoxy. /.vo-butoxy, .vec-butoxy, tert-buXoxy or «-hexyloxy. The term "(C]-C^)a!koxy" (x being an integer) refers to a straight or branched chain alkoxy group containing I to x carbon atoms. The term "halogen" refers to fluorine, chlorine, bromine or iodine, and preferably to fluorine or chlorine. The term "cycioalkyl", used alone or in combination, refers to a saturated cyclic hydrocarbon moiety containing 3 to 6 carbon atoms and preferably 3 to 5 carbon atoms. Representative examples of cycioalkyl groups include, but are not limited to. cyclopropyl and cyclopentyl. When it is written that R^ is the residue of an amino acid, it is meant thereby that R-COOH is the corresponding amino acid. ,; ';, The term "pharmaceutically acceptable salts" refers to non-toxic, inorganic or organic acid and/or base addition salts. Reference can be made to "Salt selection for basic drugs", Jf?f. J. Pharm. (1986), 33, 201-217. Unless used regarding temperatures, the term "about" placed before a numerical value "X'" refers in the current application to an interval extending from X minus iO% of X to X plus 10% of X, and preferably to an interval extending from X minus 5% of X to X plus 5% of X. in the particular case of temperatures, the term "abouf placed before a temperature "Y" refers in the current application to an interval extending from the temperature Y minus 10°C to Y plus lO'^C, and preferably to an interval extending from V minus 5°C to Y plus 5°C\ besides, room temperature shall mean in the current patent application 25X. 'cE, wherein In particular, the invention relates lo compounds of formula I that are also compounds of formula ICE R' represents OH, OPO3H2 or OCOR^ R^ represents H. OH or OPO3H2; A represents N or CR^; R^ represents fluorine; R'' represents H, (C1-C3) alkyl or cycloalkyi; R is the residue of a naturally occurring amino acid (in particular the residue of Ala); R*' represents H or alkoxy; and n is 0 or I; and to salts (in particular pharmaceutically acceptable salts) of compounds of, formula 1C1£. ^ According to a first main embodiment of this invention, the compounds of formula I are such that n is 0. Such compounds will be hereafter referred to as "compounds of formula I5". According to one particular variant of the first main embodiment, the compounds of formula I5 will be such that they have the following stereochemistry: According to another variant of the first main embodiment, the compounds of formula will be such that they have the following stereochemistry: 152 According to a second main embodiment of this invention, the compounds of formula I are such that n is I. Such compounds will be hereafter referred to as "compounds of formula h,". According to a further main embodiment of this invention, the compounds of will be such that they are also compounds of formula l|> formula wherein R' represents H or OH; A represents N or CR*^; R"^ represents fluorine: R* represents H, (C1-C3) alkyl or cycioalkyi; R^' represents H or alkoxy; and ' ji n is 0 or ]. According to yet another main embodiment of this invention, the compounds of formula I will be such that they are also compounds of formula IPDG r, h'DG wherein R' represents OH and R' represents OPO3I-I2, or R' represents OPO3H2 or OCOR"'^ and R- represents H, OH or OPO3H2; A represents N or CR^; R' represents fluorine; R represents H. (C1-C3) alkyl or cycloalkyi; R^ is the residue of a naturally occurring amino acid (in particular the residue of Ala); R represents H or alkoxy; and n is 0 or 1. According to a particular embodiment of this invention, the compounds of formula 1 will be such that A represents N. N ■f According to another particular embodiment of this invention, the compounds of. formula I will be such that A represents CR". In such case, R" will preferably represent H or alkoxy (and in particular H or methoxy). According to an important variant of this invention, the compounds of formula I will be suchthat R'isOH. According to another important variant of this invention, the compounds of formula ! will be such that R' is OPO3H3 or OCOR^ According to yet another important variant of this invention, the compounds of formula I will be such that R^ is H. According to yet another important variant; of this invention,: the compounds of formula 1 will be such that R^ is OH. ) '? ! , ■ According to a further important variant of this invention, the compounds of formula 1 will be such that R" is OPO^H^. J ., Preferably, the amino acid residue R"'^ is such that R''-COOH represents a natural amino acid (notably Ala). ,; ■' ' Preferred compounds of formula 1 are also those wherein at least one of the following characteristics is present: <• A represents CR^; <* R' represents OH or OPO3H2; ♦> R^ represents H or OH; *> R^ represents fluorine; •> R'^ represents (C|-C3)alkyl or cycloalkyi, More preferred compounds of formula I are those wherein at least one of the following characteristics is present: *> n is 0; •t* A represents CR'^, R*^ representing H or alkoxy (and preferably H or methoxy); •> R represents OH: <• R^ represents H or OH; ♦ R^ represents fluorine; ♦t* R"* represents cycloalkyi. ■i " Even more preferred compounds of formula = l are those wherein at least one of the following characteristics is present: •> n is 0; <* A represents CR^, R^ representing H or methoxy; *> R' represents OH; *> R^ represents H or OH (and notably OH); <• R represents fluorine; *> R'^ represents (C3-C5)cyc!oalkyl (and in particular cyclopropyl). The following compounds of formula 1 arc particularly preferred: - l-cyclopropyl-6-fluoro-7-{4-[2-fluoro-4-((7?)-5-hydroxymethyl-2-oxo-oxazolidin-3-yi)-phenoxymethyl]-4-hydroxy-piperidin-f-yl}-4-oxo-I,4-dihydro-quino!ine-3-carboxyiic acid; - l-cyclopropyl-6-fiuoro-7-{4-[2-fluoro-4-((7?)-5-hydroxymethyl-2-oxo-oxazolidin-3-yl)-pI]enoxymethyl]-piperidrn-!-yl}-4-oxo-I,4-dihydro-quino!(ne-3-carboxyltc acid; - !-cyclopropyi-6-fluoro-7-{4-[2-fluoro-4-((R)-5-hydroxymethyl-2-oxo-oxazolidin-3-yl)-phenoxymethyl]-4-hydroxy-piperidin-l-yl)-4-oxo-l,4-dihydro-[l,8Jnaphthyridine-3-carboxylic acid; - 7-(4-(4-[(7?)-5-((51-2-amino-propionyIoxymethyl)-2-oxo-oxazolidin-3-yI]-2-fiuoro-phenoxymelhyl}-4-hydroxy-piperidin-1-yl)-l-cyclopropyl-6-fluoro-4-oxo-1.4-dihydro-quinoiine-3-carboxylic acid; - 1 -cyclopropyl-6-fluoro-7-{4-[2-fluoro-4-((y?)-2-oxo-5-phosphonooxymethyl- , oxazolidin-3-yi)-phenoxymethyl]-4-hydroxy-piperidin-l-yl}-4-oxo-l,4-dihydrof quinoline-3-carboxylic acid; - l-cyclopropyI-6-fluoro-7-{(7?)-3-[2-fluoro-4-((7?)-5-hydroxymethyl-2-oxo-oxazolidin-3-yl)-phenoxymethyl]-3-hydroxy-pyrrolidin-1-yl}-4-oxo-l,4-dihydro-quinoline^ 3-carhoxylic acid: - l-cyclopropyi-6-fluoro-7-{(.?)-3-'[2-nuoro-4-((7?)-5-hydroxymethyi-2-oxo-oxazolidin-3-yl)-phenoxymethyl]-3-hydroxy-pyrrolidin-i-yl}-4-oxo-l,4-dihydro-quinoline- 3-carboxylic acid; - l-cyclopropyl-6-fluorb-7-{(7?)-3-[2-fluoro-4-((7?)-5-hydroxymethyl-2-oxo-oxazolidin-3-yl)-phenoxymethyl]-3-hydroxy-pyrrolidin-l-yl}-8-methoxy-4-oxo-l,4-dihydro-quinoline-3-carboxylic acid; - l-cyclopropyl-6-fluoro-7-{(.S^-3-[2-fluoro-4-((7?)-5-hydroxymethyl-2-oxo-oxazolidin~ 3-yl)-phenoxymethyl]-3-hydroxy-pyrroiidin-l-yl}-8-methoxy-4-oxo-l,4-dihydro- quinoline-3-carboxylic acid; - l-cyclopropyl-6-fluoro-7-{(7?)-3-[2-nuoro-4-((7?)-5-hydroxymethyl-2-oxo-oxazolidin- 3-yl)-phenoxymethyl]-pyrrolidin-l-yl}-4-oxo-l,4-dihydro-quinoline-3-carboxylic acid; 10 - l-cyclopropyl-6-fluoro-7-{(50-3-[2-fluoro-4-((7?)-5-hydroxymethyl-2-oxo-oxazolidin-3-yl)-phenoxymethyl]-pyrroiidin-l-yl}-4-oxo-l,4-dihydro-quinoline-3-carboxylic acid; - l-cyclopropyl-6"fluoro-7-{(i^)-3-[2"fIuoro-4-{(7?)-5-hydroxymethyl-2-oxo-oxa2oiidin- 3-yl)-phenoxymethyl]-pyrrolidin-l-yl}-8-methoxy-4-oxo-1.4-dihydro-quinoline- i ] 3-carboxylic acid; J - l-cyclopropyl-6-fluoro~7-{(5)-3-[2-fluoro-4-((i?)-5-hydroxymethyl-2-oxo-oxaio!idin-3-yi)-phenoxymethyl]-pyrrolidin-l-yl}-8-methoxy-4-oxo-l,4-dihydro-quinoline-3-carboxylic acid; I I - l-cyclopropyl-6-fluoro-7-{4-[2-fluoro-4-((i?)^5-hydroxymethyU2-oxo-oxazolidin-3-yl)-phenoxymethyl]-4-phosphonooxy-piperidin-l-yl}-4-oxo-],4-dihydro-quinoline-3-carboxylic acid; ' ,; „ ; .1 - l-ethyl-6-fluoro-7-{4-[2-fiuoro-4-((-/?)-5-hydroxymethyl-2-oxo-oxazolidin-3-yl)-phenoxymethyl]-piperidin-l-yl}-4-oxo-l,4-dihydro-quinoHne-3-carboxylic acid; - 7-(4-{4-[(-/?)-5-{(5^-2-amino-propiony!oxymethyl)-2-oxo-oxazolidin-3-y!]-2-fluoro-phenoxymethyl}-pJperidin-l-y!)-]-cyclopropy]-6-fluoro-4-oxo-l.4-dihydro-quiholine-3-carboxylic acid; - 6-fluoro-7-{4-[2-fluoro-4-{(7?)-5-hydroxymethyl-2-oxo-oxazolidin-3-yl)- :; phenoxymethy!]-4-hydroxy-piperidin~l-yl}-4-oxo~i,4-dihydro-quinoline-3-carboxylic acid; '! - 6-f]uoro-7-{4-[2-f]uoro-4-({7?)-5-hydroxyiTietby!-2-oxo-oxazolidin-3-yl)-phenoxymethyl]-4-hydroxy-piperidin-l-yl}-4-oxo-l,4-dihydro-[l,8]naphthyridine- 3-carboxylic acid; '^ t ^ ' ! as well as salts thereof {and in particular pharmaceutically acceptable salts thereof). .< .1 Chimeric derivatives of formula I are suitable for the use as medicaments, particularly as antimicrobial agents, in human medicine but also in veterinary medicine in the treatment of species like pigs, ruminants, horses, dogs, cats and poultry. jj ■!' ■' Chimeric derivatives of formula I according to the present invention are also useful for li the manufacture of a medicament for the treatment of infections (notablyj-bacterial infections or protozoal infections) and disorders related to infections (notably disorders related to bacterial infections or to protozoal infections). ij The compounds according to this invention are particularly active against bacteria and bacteria-like organisms. They are therefore particularly suitable in human, as well as in animals, for the prophylaxis and chemotherapy of local and systemic infections caused by these pathogens as well as disorders related to bacterial infections comprising pneumonia, otitis media, sinusitis, bronchitis, tonsillitis, and mastoiditis related! to infection by Slreptococci4S pneumoniae, \ Haemophilus influenzae, Moroxella catarrhahs^ Staphylococcus aureiis, Enlerococciis faecalis, E. faecium, E. casseliflavus, S. epidermidis, S. haemolyticus, or Peptosfreptococcus spp.\ pharyngitis, rheumatic fever, and glomerulonephritis related to infection by Streptococcals pyogenes. Groups C If and G streptococci. Corynebacterium diphtherial or Actinobacillus haemolyticimn respiratory tract infections related to infection iby Mycoplasma pneumoniae, Legionella I-•I pnetnnophila. Streptococcus pneumoniae, Haemophilus influenzae, or Chlamydia pneumoniae: blood and tissue infections, including endocarditis and osteoiiiyelitis. caused by S. aureus, S. haemolyticus, E. faecalis, E. faecium, E. chrans, including strains resistant to known antibacterials such as, but not limited to, beta-lactams. vancomycin, aminoglycosides, quinolones,' chloramphenicol,, tetracyclines and macrolides; uncomplicated skin and soft tissue infections and abscesses, and puerperal fever related to infection by Staphylococcus aureus, coagulase-negative staphylococci {i.e., S. epidermidis, S. haemolyticus, QXC.),^Streptococcus pyogenes. Streptococcus agalactia^. Streptococcal groups C-F (minute colony streptococci), iiviridans streptococci, Corynebacteriimi minutissimum, Clostridium spp., or Bartonella henselae; uncomplicated acute urinary tract infections| related to infection by Staphylococcus aureus, coagulase-negative staphylococcal species, or Enterococcus spp.; urethritis and cervicitis: sexually transmitted diseases related to infection by Chlamydia trachomatis, ii ' .;._ Haemophilus ducreyi, Treponema pallidum:', Ureaplasma urealyiicum, or Neiserria gonorrhoeae; toxin diseases related to infection by .S". aureus (food poisoning and toxic shock syndrome), or Groups A, B, and C streptococci; ulcers related to infection by ip Helicobacter pylori; systemic febrile syndromes related to infection hy-Borrelia recurrentis; Lyme disease related to infection by Borrelia burgdorferi; conjitnctivitis, keratitis, and dacrocystitis related to infection by Chlamydia trachomatis. Neisseria gonorrhoeae, S. aureus, S. pneumoniae, S. pyogenes, H. influenzae, or Listeria spp.; disseminated Mycobacterium avium complex (MAC) disease related to infection by Mycobacterium avium, or Mycobacteriimi[ intracellulare; infections caused by Mycobacterium tuberculosis, M. leprae, M. poratuberculosis, M. kansasii, or M. chelonei; gastroenteritis related to infection by Campylobacter jejuni; intestinal protozoa related to infection by Crypto.sporidmm spp.; odontogenic infection related to infection by viridans streptococci; persistent cough related to infection by Bordetella pertussis; gas gangrene related to infection by Clostridium perfringens or Bacteroides spp.; and atherosclerosis or cardiovascular disease related to infection by Helicobacter pylori or Chlamydia pneumoniae. Compounds of formula ! according to the present invention are further useful for the preparation of a medicament for the. treatment of infections that are mediated by bacteria such as E. coli, Klebsiella pneumoniae and other Enterobacteriaceae. Acinetobacter spp., Stenothrophomonas malfophilia. Neisseria meningitidis. Bacillus cereus. Bacillus anthracis, Corynebacteriwu spp., Propionibacterium acnes and bacteroide spp. In addition, compounds of formula 1 according to the present invention are further useful for the preparation of a medicament for the trsaXmenX of infections that are mediated by Clostridium difficile. Compounds of formula ( according to the present invention arc further useful to treat protozoal inl'ections caused by Plasmodium malaria, Plasmodium falciparum. Toxoplasma gondii^ Pneumocystis carinii, Tiypanosoma hrucei and Leishmania spp. The preceding lists of pathogens are to be interpreted merely as examples and in no way as limiting. , i As well as in humans, bacterial infections canalso be treated in other species like pigs, ruminants, horses, dogs, cats and poultry. . 1 herefore. the compounds of formula 1 or ihelr pharmaceulically. acceptable salts can be used for the preparation of a medicament, and are suitable, for the prevention or treatment of bacterial infections (notably those caused by the pathogens mentioned in the lists above). The compounds of formula I and their pharmaceutical ly acceptable salts can be used as medicaments, e.g. in the form of pharmaceutical compositions for enteral or parental administration. The production of the pharmaceutical compositions can be effected in a manner which will be familiar to any person skilled in the art (see for example Mark Gibson, Editor, Pharmaceutical Preformulation and Formulation, IHS Health Group, Englewood, CO, USA, 2001; Remington, The Science and Practice of Pharmacy, 20th Edition, Philadelphia College of Pharmacy and Science) by bringing the described compounds of formula I or their pharmaceuticaliy acceptable salts, optionally in combination with other therapeutically valuable substances, into a galenical administration form together with suitable, non-toxic, inert, therapeutically compatible solid or liquid' carrier materials and, if desired, usual pharmaceutical adjuvants. Another aspect of the invention concerns a method for the treatment of an infection comprising the administration to the patient of a pharmaceuticaliy active amount of a compound according to formula I or of a pharmaceuticaliy acceptable salt thereof. Moreover, the compounds of formula I may also be used for cleaning purposes, e.g. to remove pathogenic microbes and bacteria from surgical instruments or to make a room or an area aseptic. For such purposes, the compounds of formula i could be contained in a solution or in a spray formulation. Any reference to a compound of formula I. I51. I52, 1(„ In or IPDG is to be understood as referring also to a salt (especially a pharmaceuticaliy acceptable salt) of a compound of formula I, I51, I52, le. ID or IPDG respectively, as appropriate and expedient. Besides, any preferences indicated for the compounds of formula 1 {whether for the compounds themselves, salts thereof, compositions containing the compounds or salts thereof, uses of the compounds or salts thereof, etc.) apply mitlali.s mutandia to compounds oi formula ICE, the compounds of formula I5, the compounds of formula I51, the compounds of formula I52, the compounds of formula U, the compounds of formula \t and the compounds of formula IPDG- According to the invention, the compounds of formula I can be prepared by the process described hereafter. Preparation of the compounds of formula I The following abbreviations are used throughout the specification and the examples: AcOH acetic acid 14 AD-mix a AD~mix [3 Alloc aq. BnBr Boc r-BuOK Cbz DBU DCM DIAD DIPEA DMA DMAP DMF DMSO EA EDC ESI ether or EtjO PC h Hex MeCN MCPBA MeOH MS NaOMe ].4-/?/,s'(dihydroquinine)phthala2ine. K.^FeCCN),,. K2CO3 and K2OSO4.2H2O !j ■ ;. ' i! l,4-/)/.s'(dihydroqiiinidine)phthalazine, K3Fe(CN)6, K2CP3 and K2OSO4.2H2O allyloxycarbonyl aqueous benzyl bromide re/V-butoxycarbonyl potassium /e^/-butylate benzyloxycarbonyl I.8-dia2abicyclo[5.4.0junaec-/-ene dichloromethane diisopropyl azodicarboxylate A',7V^diisopropylethylamine dimethylacetamide '■ - 4-dimethy)aminopyndine MvV-dimethylform amide dimethylsulfoxide '. ethyl acetate ' I; l-(dirnethyiaminopropyl)-3-ethylcarbodiimide hydrochloride Electron Spray lonisation .[ diethyl ether | flash chromatography } ■i hour ;j tt-hexane 'f acetonitrile mefa-chloroperbenzoic acic methanol Mass Spectroscopy sodium methylate 15ii NMP A^-methylpyrroiidinone org. organic Pd/C or Pd(0H)2/C palladium or dihydroxypalladium on charcoal PPh3 triphenylphosphine It room temperature sat. saturated Si02 silica gel TBDMSCi r(?r/-butyldimethylsilyl TEA triethylamine TFA trifluoroacetic acid THF tetrahydrofuran TMSCI trimethylsiiyi chloride General prepa ration routes: The novel compounds of formula I can be manufactured in accordance with the present ■invention by a) reacting the compound of formula II ■: II with a compound of formula ill [CH2ln R N—A / OH RT—O wherein n. A. R and R'' are as defined in formula I and R' is (C|-C3)alkylsultonyl (e.g. methylsulfonyl), trifluoromethylsulfonyl or arylsulfonyl (e.g. piienyl- or /7-tolyl"Stilfonyl) and R" is OU or H. or R" and R^ together form a bond (i.e. R^ and OR form, together,with the carbon atoins that carry them, an epoxide ring), preferably between about 10°C and 100°G (more preferably between abopt 40°C and 80°C), in the presence of an inorganic, base such as K2CO3 or an organic base such as TEA in an organic solvent (e.g. DMF); or b) reacting a compound of formula IV wherein n is as defined in formula I and R is H or OH, O—R' with a compound of formula V wherein A, R^ and R" are as defined in formula [, Y is halogen and R^ is hydrogen, ■i BF2 or B(OC(=0)(Ci-C4)alkyI)2, (CrC5)alkyl (e.g. methyl, ethyl, ^-propyl, iso-propyl or tert-buty\\ allyl, aryl-(Ci-C5)alkyl (e.g. benzyl, p-nitrobenzyi or p-methoxybenzyl), tn-(C[-C5)alkyIsi]yl (e.g. trimethyJsilyl or /^r/-butyldimefhylsilyJ) or diaryl-(C|-C5)alkylsilyl (e.g. tov-butyldiphenylsilyl), preferably between about lO^C and lOO^C. more preferably between Libout 40°C and 80°C in the presence of an organic base, such as TEA or DIPEA. in'an organic solvent, e.g. NMP: 1 or c) converting a compound of formula I wherein R' is OH into a compound of formula I wherein R' is OPO3H2 or OCOR'^, R"' being the residue of a naturally occurring amino acid, of the enantiomer of a naturally occurring amino acid or of dimethylaminoglycine; f if i 1 ■I ■ I ■ ,i I or " ■I d) converting a compound of formula II>G !) ' O F wherein R' is OPO' (PG' being a protecting group for an alcohol function), R^ is OH. and n. R"^. R"^ and A have the same meaning as in formula I. into a compound of formula ( wherein R^ is OPO3H2 and subsequently removing the protecting group PG', examples of suitable protecting groups PG' being alkylsilyl or diarylalkylsilyl groups such as trimethylsilyl, tert-butyldimethylsilyl or tert-butyldiphenylsilyl {strategies to introduce these protecting Igroups and to remove them have been summarized in Protecting groups, Kocienski. P.J.. Thieme (1994)); M or e) converting a compound of formula VI OR- o o V] wherein R is (C|-C5)a!kyl (e.g. methyl, ethyl, w-propyl, wo-propyl or ten-bi\iy\). aryl-(Ci-C5)alky! (e.g. benzyl, /?-nitrobenzy! or p-methoxybenzyl), allyl, tri-(C|-C5)alkyisilyi (e.g. trimethylsilyl or /er/-butyldimethy(sily!) or diaryl-(CrC5)alkylsiIyI (e.g. /crz-butyldiphenylsilyl) and n. A, R', R". R' and R"* are as defmed in formula I into the corresponding compound of formula I by hydrolysis, saponification or hydroge no lysis (e.g. as reviewed in Protecting groups, Kocienski. P.J., Thieme {\99A)). Concerning the above process, the following should be noted: •> regarding variant a), the compound of formula III could also be replaced by'an ester thereof, i.e. a compound of formula IIIE RT—O .3 O—R 10 Uh wherein, n, A, R^, R^ R'' and R' are as defined in formula III and R'° represents alkyl, allyl or arylalkyl, in which case an ester deprotection step would follow the 19 »> reaction of the compound of formula II!K with the compound of formula 11 (general methods to perform the ester deprotection step have been reviewed in Protecting groups, Kocienski, P..I.. Thieme (1994)); regarding variant a), the compound of formula li could also be replaced by a silyl ether thereof, i.e. a compound of formula Ilpo O F II PG wherein PG^ represents a silyl protecting group for an alcohol function such as a tri-(Ci-C5)alkyIsilyI (e.g. trimethylsilyl or /erz-butyldimethylsilyl) or diary!-(Ci-C5)alkylsilyl (e.g. /er/-b(ity!diplienylsiiyi), in which case a deprotection step would follow the reaction of the compound of formula III or III|-; with the compound of formula IIpo (general methods to perform such reactions have been reviewed in Protecting groups, Kocienski, P.J., Thieme (1994)), it being understood that when R^ is H, the coupling between compound of formula IIPG and the compound of formula 111 or Mln can also be performed under Mitsunobu conditions as described in Synthesis (1981), 1, 1-28, and notably conditions wherein the I 'i reaction is carried out in the presence of DJAD and PPh3; ■ •> regarding variant b), the compound of formula IV could also be replaced by a compound of formula IVp PG^O IVp wherein n and R" are as defined in formula IV and PG^ represents a protecting group for an alcohol function (e.g. an alkylsilyl or diarylalkylsily! group such as trimethylsilyl, /^/-/-butyldimethylsilyl or /^r/-butyldiphenylsilyl), in which case the appropriate deprotection step would follow the reaction of the compound of 20 formula IVp with the compound of formula V (general methods to perform such reactions have been reviewed in Protecting groups, Kocienski, P..I.. Thieme (1994)); ♦t* regarding variant b). when R*^ is not H. an additional ester deprotection step is required (general methods to perform such reactions have been reviewed in Protecting groups, Kocienski, P.J., Thieme (1994)), except for the cases wherein R is BF2 or B(OC(=0)(C!-C4)alkyl)2 where the hydrolysis takes place already during the acidic work-up; *> regarding variant c), the compound of formula 1 wherein R' is OH can be replaced by a compound of formula VI wherein R' is OH and R" is H or OH, in which case an additional ester deprotection step is required (general methods to perform such reactions have been reviewed in Protecting groups. Kocienski. P.J., Thieme (1994)); *;• concerning variants c) and d): o compounds of formula I wherein R' or R^ is OPO3H2 can be obtained by deprotection of the corresponding compounds wherein R' or R" is OPO(OR)2 and R is ally) or benzyl (according to the nature of R, various methods for deprotection may be used as reviewed in Protecting Groups. Kocienski, P., J., Thieme (1994), (ike for example catalytic hydrogenation over a noble catalyst such as palladium or hydrolysis with hydrobromic acid in a solvent such as AcOH when R is benzyl); o compounds of formula 1 wherein R' is OCOR^ can be obtained for example by reaction of compounds of formula i wherein R' is OH or compounds of formula Vi wherein R' is Oil and R^ is H or Oil with dimethylaminoglycine or a //-protected amino acid followed by deprotection of the amino group under standard conditions known to one skilled in the art (an additional ester deprotection step being required in the case of a reaction with a compound of formula VI). The compounds of formula 1 obtained according to the abovementioned general preparation methods may then, if desired, be converted into their salts, and notably into their pharmaceutically acceptable salts. Besides, whenever the compounds of formula I are obtained in the form of mixtures of enanttomers, the enantiomers can be separated using methods known to one skilled in the art (e.g. by formation and separation of diastereomeric salts or by chromatography 21 the form of mixtures oi diasteromers they may be separated by an appropriate combination of silica gel chromatography, HPLC and crystallization techniques. Preparation of the yaripus Preparation of the compoinicioffornmla II The compound of formula II can be obtained by hydrogenation of compound VI! Vo/'"V^ VII over a noble catalyst such as palladium or platinum on charcoal in a solvent.such as THF, MeOH or AcOEt between 0°C and 40°C or by hydrolysis of in presence Of a solution of HBr in water or AcOH between 0°C and $0°C in a solvent such as AcOH. Preparation of the compounds offorimila III The compounds of formula HI can be prepared as summarized in Scheme 1 hereafter. R2 [CHdfTA V 1 RMCH2]frOR° HO— VI11 IIU:R' = H Ills: lt' = S02k" Scheme 1 In Scheme 1, R^ is H, alkyl, ally! or arylalkyl, and the other symbols are as before. Compounds of formula Ills wherein R" is H or OH, R' is S02R'\ R" being alkyl. trifluoromethyl or aryl like phenyl or/7-tolyl are obtained (Scheme I) from compounds of formula IIU wherein R' is H by reaction with the corresponding sulfonyl chlorides in presence of an organic base such as TEA in a solvent such as DCM or THF between -IO°C and 50*^0. Compounds of formula IIU are prepared by reaction of the compounds of formula V with the piperidines of formula Vlll in the presence of an organic base such as TEA or DIPEA between 40°C and lOOX in a solvent such as THF. DMF or NMP. If R^ is benzyl, the carboxylic acid of formula Ills is liberated according to standard procedures as described in Protecting groups. Kocienski, P.J., Thieme (1994) (e.g. hydrogenation over Pd/C). The compounds of formula III wherein R^ and R' together form a bond, i.e. the compounds of formula IIIo lllo can be prepared by intramolecular cyclisation of the compounds offoirnu\a JMs wherein R^ is OH in the presence of an organic base (e.g. TEA) or an inorganic base (e.g. K^COT or an alkali methylate such as NaOMe or an alkali hydride such as NaH). : ■1 Preparation of the compounds of formula IV '■ ' The compounds of formula IV can be prepared as summarized in Scheme 2 hereafter. N—PG- HO-^ r^~~-^ \^=/ HO. IX HO^X N—f ^)—O- Scheme 2 The compounds of formula IV can be obtained by deprotecting a compound of formula X wherein PG"* represents a nitrogen protecting group such as alkoxycarbonyl (e.g. Boc). benzyloxycarbony! (e.g. Cbz), Alloc or benzyl. General methods to perform such protection/deprotection sequences of secondary nitrogen atoms have been reviewed in Protecting groups. Kocienski. P..I., Thieme (1994). The compounds of formula X wherein R^ is OH are obtained by reacting a compound of formula II with a compound of formula IX wherein either R" is OH and R' is:S02R". R" being alkyl, trifluoromethyl or aryi like phenyl or ;?-toIyi, or R" and R''together form a bond (epoxide). Said epoxide can be obtained from compounds of formula IX, wherein R" is OH and R' is SOJR" upon treatment with either an organic base such as TEA. pyridine or DBU or an inorganic base such as K2CO3 in a solvent such as THF. ether or DCM between -lO'^C and 40"C. Compounds of formuta X. wherein R" is H are obtained by reacting a compound of folmula li with a compound of formula IX wherein R is SO2R . Compounds of formula IX are either commercially available (e.g. compounds of formula IX wherein PG"* = Boc, n = 0 and R^ and R^ form an epoxide or wherein PG = Boc, n=l and R" = R' = 0H) or made as explained later on. Alternatively, compounds of formula X can be obtained by reaction of the compound of formula II with compounds of formula IX wherein R^ is H under Mitsunobu conditions. Preparation oflhe compounds of formula V Compounds of formula V wherein R** is H and Y halogen are commercially available (e.g. compounds wherein R"* = F, R" = cyclopropyi and A = CH, CF or COMe, or R"* = F. R" = Et and A = CH or CF, or R^ == F, R" = cyclopropyi and A = N). Compounds of formula V wherein R is BF2 or B(OC(=0)(C|-C4)alkyl)2 are obtamed from compounds of formula V wherein R** is H according to WO 88/07998. Preparation of the compounds offormi^Ia VI The compounds of formula VI can be obtained by coupling compounds of formula IV or, alternatively, compounds of formula IVp as previously defined with compounds of formula V as previously defined except that R^ represents (CrC5)aIkyl (e.g. methyl, ethyl, H-propyl, /.vo-propyl or /erZ-butyl), aryl-(Ci-C5)alkyl (e.g. benzyl,/J-nitrobenzyl or p-methoxybenzyl), allyl, lTi-(Ci-C5)alkylsiIyI (e.g. trimethylsilyl or leri-butyldimethylsiiyl) or diaryl-(C|-C5)alky!silyl (e.g. /er/-buiyidiphenylsiiyl). under the same conditions as those described for the reaction of the compounds of forinula IV with the compounds of formula V. If the compounds of formula IVp are used, the deprotection step can be carried out after the coupling reaction. Preparation of the compound offonmih VII The compound of formula VII can be obtained according to WO 2004/096221. Preparation oflbe compounds of formula VIII Compounds of formula VIII are either commercially available (R" = H) or obtained by deprotection of compounds of formula IX (R^ = OH and R'= H), for example by treatment oi" the corresponding Boc protected compounds with TFA or by hydrogenation of the corresponding Cbz protected compounds over Pd/C. Preparation of I he compounds of formula JX The compounds of formula IX can be prepared from the methyhdene derivatives of formula XI as summarized in Scheme 3 hereafter. O^y N—PG' I\r XI \\a: R' = H IXA: R' = S02R" Scheme 3 The compounds of formula IX/;, i.e. the compounds of formula IX wherein R" is H or OH and R' is SO2R", are prepared from the corresponding compounds of formula \Xa wherein R' is H using the same methods used for the conversion of compounds of formula IIIA into compounds of formula Ills- Compounds of formula \Xa either are commercially available (R^ = H) or are obtained from the known methylidene derivatives of formula XI (e.g. those wherein n = 0 and PG^ = benzyl, Boc or benzyloxycarbonyl - see EP 241206 and EP 550025; or those wherein n-1 and 25 PG ^benzyl. Boc which are commercial) either by osmium tetroxide catalyzed c?.9-dihydroxylation or by its asymmetric version (Sharpless dihydroxylation using AD-mix a or (3) as described in ./. Am. Chem. Soc. (1988), HO, 1968 (R^ = OH). Compounds of formula IXc, i.e. the compounds of formula IX wherein R^ and R^ together form a bond (epoxide), are obtained either by intramolecular ring closure of compounds of formula \Xb with an inorganic base such as K2CO.i orNaH or an organic base such as TEA or DBU, or by epoxidation of the methylidene double bond with a peracid such as MCPBA. Alternatively, compounds of formula IXc can also be obtained by reaction of the corresponding oxo derivatives {commercial when n = 0 or 1 and PG^ = Cbz or Boc) with trimethylsulfoxonium iodide or trimethylsulfonium iodide in presence of an alkali hydroxide such as KOH in a polar solvent such as MeCN between 20 and 100°C (as described in ./. Am. Chem. 5oc. "(1965), 87, 1353-1364 and Tetrahedron Lelt. (1987), 28, 1877-1878). The following examples further illustrate the preparation of the pharmacologically active compounds of the invention but do not limit the scope thereof. EXAMPLES All temperatures are stated in °C. All analytical and preparative HPLC investigations on non-chiral phases are performed using RP-C18 based columns. Analytical HPLC investigations are performed on two different instruments with cycle-times of-^2.5 min and -3.5 min respectively. Unless otherwise stated, the values indicated for MS correspond to the main peaks ((M+H)* with a variation of+/- 0.5 unit). In NMR spectra, coupling constants J are given in Hz. Standard work-up procedure: After dilution in the appropriate org. solvent (see corresponding Example text); the org. phase is separated and sequentially washed with water and brine. In case of reaction performed in a water soluble solvent (e.g. MeOH, THF or DMF), the combined aq. layers are back-washed with the same solvent used to perform the workup. The combined org. phases are dried over MgS04 and filtered. The filtrate is evaporated under reduced pressure. Standard chromatography procedure: 26 The crude material is dissolved in the minimum of eiuent (see corresponding Example text) and chromatographed over Si02. The relevant fractions were pooled and evaporated under reduced pressure. Example 1: l-cycIopropyl-6-f!uoro-7-{4-[2-fliioro-4-((i?)-5-hydroxyinethyI-2-oxo-oxazolidin-3-yl)-phenoxymethyll-4-hydroxy-piperidin-l-yl}-4-oxo-l,4-dihydro-qiiinoIine-3-carboxylic acid: 1.1. (R)-3-{3-Jl2.(oro-4-hyd}-oxy'phenyl)-5-hydroxymeih\'l-oyazo1idifi-2-one: A solution of (7('>3-{4-benzyloxy-3-fluoro-phenyl)-5-hydroxymethyl-oxazolidin-2-one (6.34 g, prepared according to WO 2004/096221) in THF/MeOH (1:1; 200 ml) was hydrogenated over Pd/C 10% (I g) overnight. The catalyst was filtered off the filtrate evaporated under reduced pressure and the residue stirred in EA. The crystals were collected by filtration, affording 3.16 g (70% yield) of a colourless solid. 'H NMR {DMSOrff,; ft ppm): 3.5 (m. I H). 3.64 (m. ] H), 3.74 (dd. .1 = 8.8. 6:4. 1 H). 3.99 (t, J = 8.8, 1 H), 4.64 (m, 1 H), 5.16 (t. .1 = 5.6, 1 H). 6.93 (dd, .1 = 9.7. 8:8. i H), 7.08 (ddd, J = 8.8, 2.6, 1.2. 1 H), 7.45 (dd, .1 = 13.5, 2.6. 1 H), 9.66 (s. 1 H). ^ MS (ESI): 228.1. '^ i I J.ii. 4-[2-f}iioro-4-((R)-5'hydroxymethyl-2'Oxo-oxazoUdm'S-yl)-pherioxymelhyl]- ' ii - ■ 4-hydroxy-piperidine-1 -carboxylic acid benzy][esier: ; A solution of intermediate l.i (1.27g) and l|-oxa-6-aza-spiro[2.5]octane-6-carboxylic acid benzyl QSter {).60 g; prepared accord'mgto I IS 4244961) were dissolved'in DMF (15 ml) and treated with Na2C03 (1.16 g). The mixture was heated at 100°C overnight. The residue obtained after workup (DCM) was stirred in EA, and the solid was collected by filtration and sequentially washed with EA and Hex, affording 2.52 g (94.5% yield) of a beige solid. 'H NMR(DMSOd6;5ppm): 1.57 (m. 4 H), 3.14 (m, 2 H), 3.54 (m. 1 H), 3.64 (m, I H), 3.79 (m, 5 H), 4.03 (t, J = 9.1, I H), 4.66 (m, 1 H). 4.78 (s, 1 H), 5.05 (s. 2 H). 5.16 (t. .1 = 5.6, 1 H), 7.18(m, 2H), 7.32(m, 5 H), 7.55 (d, J = 12, 1 H). MS (ESI): 475.0. l.iii. (R)-S-[3-fluoro-4-(4-hydroxy-piperidm-4-yimethoxy)-phenyi]-5-hydroxymelhyl' oxazoUdm-2-one: A suspension of intermediate l.ii (2.5 g) in EA/MeOH (1:1; 100 ml) was hydrci'genated !l over Pd/C lor 48 h. The suspension was heated'at 40°C and the catalyst was llltered off. The filtrate was evaporated under reduced pressure affording 1.61 g (89% yield) of a !i . ;; ■ yellow powder. != Ij i 'H "NMR (DMSOd6; 6 ppm): 1.4-1.63 (m. 4 H)'. 2.67 (m, 2 H). 2.83 (m, 2 H), 3.53 (dd, J = 4.0 and 12.0, IH); 3.66 (dd, .1 = 3.3 and 12.0. IH), 3.71 (s, 2H); 3.80 (ni, 1 H), ji 4.05 (t, J = 9.0, 1 H), 4.48 (s, 1 H), 4.68 (m, 1 :H), 5.20 (s, 1 H), 7.20 (m, 2 H),i7.57 (d, 1 H). "' 'i if ^ I . MS (ESI): 341.5. i; ;; J.iv. J-cycJopropyh6-jhiow-7-{4-[2-fliioro-4-((R)-5-hydroxymethyJ'2--oxo-oxazo]idir)- 3-yl)-phenoxymethyl]-4-hydroxy~pipendm-1-yi}-4-0X0-1,4-ciihydro-gumo]we- ], 3-carhoxylic acid: ': ■ ^ Ij A solution of intermediate l.iii (200 mg), 7-chloro-l-cyclopropyl~6-fluoro-l,4-dihydro- 4-oxo-3-quinolinecarbo.\ylic acid boron diacetate complex (241 mg; prepared according to WO 88/07998) and DIPEA (100 \i\) in NMP (2 ml) was stirred at 85X for '5 h. The reaction mixture was evaporated under reduced pressure and the residue was taken up in 5A/ HCl in MeOH (3 ml) and stirred. The resulting solid was collected by filtration and washed with MeOH to afford 230 mg (67% yield) of a yellow solid. ij 'HNMR(DMSOd6;5ppm): 1.66-1.35 (m, 4 H), 1.75 (d, J = 12.8, 2 H), 1.95 (m. 2 H). 3.33 (t broad, J = 11.0, 2 H), 3.57 (m, 3 H), 3.67 (dd, J = 12.3, 3.3, 1 H), 3.83 (m, 2 H). 3.92 (s, 2 H), 4.06 (t. .1 = 9.0, 1 H). 4.69 (m, 1 |H), 7.24 (m, 2 H), 7.60 (m. 2 H); 7.90 (d. .1 = 13.3, I H), 8.66(s, 1 H). \ ■ I '. MS (ESI): 585.9. I ■ '! . ^i Example 2: l-cyclopropyI-6-fluoro-7-{4-[2-fluoro-4-((/f)-5-hydroxymethyl-2-oxo- oxazoIidiii-3-yl)-phenoxymethyl]-pipericliii-J-yI}-4-oxo-1,4-dibydro-quinoline- .1 3-carboxylic acid: ; i; 2.i. (R)-3-f4-henzyloxy-3-Jhiow-phenyl)-5-(ten'huty!'dimethyl-si/any/oxymelhyl)~ oxazo/idin-2-one: I ■« A solution of TBDMSCI (3.77 g) in DCM (5 ml) was added dropwise at Q°C to a If solution of (i?)-3-(4-benzyloxy-3-fluoro-phenyl)-5-hydroxymethyl-oxazolidin-2-one (6.35 g; prepared according to WO 2004/096221) and imidazole (2.04 g);:in DMF \ ^ i 28 i| (15 ml). After stirring at rt for 16 h, the reaction mixture concentrated jn vacuo. The residue was taken up in DCM and sequentially washed with \N HCl, sat. NaHC03 aq. and brine, dried over MgS04. filtered and concentrated lo give 8.41 g (97% yield) of a colourless solid. 'H NMR (DMSOdfi; 5 ppm): 0.04 (6H. s); 0.79 (9H, s); 3.69-3.78 (2H, m). 3.86 (IH, dd. J = 3 and J = 12); 4.07 (IH, t, J = 9); 4.69-4.77 (IH, m); 5.15 (2H, s); 7.15-7.21 (IH, m); 7.25 (IH, t, J = 9); 7.30-7.36 (IH, m); 7.37-7.50 (4H, m); 7.57 (IH. dd, .1 = 3 and J = 14). 2. a. (R)-5-(tert-biny}-dimeihyl-silaiiyloxymeihy})'S'(3~fluoro-4-hydroxy-pher)yl)-oxazolidiii-2-oiie : A solution of intermediate 2.i (7.22 g) in THF/MeOH (1:1; 150 ml) was hydrogenated over 10% Pd/C (150 mg) for 3 h. The catalyst was filtered off and the filtrate concentrated in vacuo affording 5.51 g (96% yield) of a colourless solid. 'H NMR (DMSOd6; 5 ppm): 0.04 (6H, s); 0.80(9H, s); 3.69-3.78 (2H, m), 3M0}-i, dd. J-3 and J = 12): 4.07 (IH, t. J = 9); 4.68-4.75 (IH. m); 6.94 (IH. t. J = 9); 7.04-7.10(lH, m);7.45(lH. dd. J = 3andJ=:i4):9.65(lH. s). ' MS (ESI): 342.2. f 2.iii. 4~{4-[(R)'5-(lert-huiyl-diniethyl-siIanyloxymethyI)-2-oxo-oxazo!idin-S-yI]'' 2-fhioro-pher}Oxyr}iethy/}-piperidme-J-carhoxylic acid teri-hiityl ester: \A suspension of 4-hydroxvmethylpiperidine-l-carhoxylic acid /er/-butyl ester (200 mg; commercial), intermediate 2.ii (317 mg) and PPhs (365 mg) in THF (5 ml) was treated dropwise over 90 min with DIAD (0.294 ml). After stirring overnight at it. the reaction mixture was worked up (toluene/Hex 1:2) and chromatographed (Hex/EA 2:1), affording 351 mg (70% yield) of an off-white solid. MS (ESI): 539.2. 2.iv. (R)-3-[3-Jlnoro-4-(piperidin-4-yJmethoxy)~pheny!]-3-hydwxymethyl-oxazo/idin-2-one: A solution of intermediate 2.iii (351 mg) in MeOH (2 ml) was treated with 5M HCl in MeOH (1 ml) and stirred at rt for 3 h. The resulting solid was collected by filtration and washed with MeOH (5 ml), affording 180 mg (85% yield) of a colourless solid. 'H NMR (DMS0d6; 5 ppm): 1.48 (2H, m); 1:89 (2H, m); 2.05 (IH, m); 2.88 (2H, t, .1= 10); 3.10 (2H. m): 3.55 (IH. m); 3.63 (IH. m); 3.78 (IH, dd, .1 = 6.4 and .1 = 8.8); 3.91 (2H, d, .1 - 6.2); 4.02 (IH, t, .1 = 8.8); 4.66 (IH.m); 5.19 (IH, t, J = 5.6); 7.i20 (2H. m); 7.56 (IH, dd, J = 2.35 and J = 14). i ii MS (ESI): 325.5. ) l f .. . . ■I !' 2.V. }-cycJopropyl-6~fliioro-7-{4-[2-fIuoro-4-((R)-54iydroxymethy}~2-oxo--oxazoUdin- S-yl)-phenoxymelhyJ]'piperidin-l-yl}-4'Oxo-I,4-dihydro-qinnoline-3 carboxylic acid: The title compound was obtained as a colourless powder in 12 % yield, starting from intermediate 2.iv (377 mg) and 7~chloro-l-cyclopropyl-6-fluoro-l.4-dihydr6-4-oxo- 3-quinolinecarboxylic acid boron diacetate icomplex (205 mg) and following the procedure of Example 1, step l.iv. | ' ; 'HNMR(DMSOd6;Sppm): 1.13-1.33 (m, 4 H), 1.45-1.6 (m, 2 H). 1.94 (dl, J = 12.0, 2 H), 2.04 (m, 1 H), 2.98 (t, J = J2.0, 2 H), 3.50-3.69 (m, 2 H),'3.73-3.89 (in, 4 H), 3.98(d, .1 = 6.2, 2 H), 4.02 (t, .1 = 9.3. 1 H), 4.66 (m, 1 H). 5.18 (t, .!■.= 5.6, 1 H),'7.21 (m. 2 H), 7.56 (m, 2 H), 7.88 (d, J - 13.5, 1 H), 8.64 (s, 1 H). \ : MS (EST): 570.2. ij ■■ !' :L ■' h Example 3: l-cyclopropyl-6-fluoro-7-{4-[2-fluoro-4-((V?)-5-hydroxymethyl-2-oxo- ■} oxazoIidin-3-yl)-phenoxymethyl]-4-hydroxy7pipendin-l-yl}-4-oxo-l,4-dihydro- [l,8]naphthyridine-3-carboxyIic acid: li A solution of 7-chloro-1-cyclopropyI-6-fluoro-i,4-d!hydro-4-oxo-1,8-naphthyridine- ■I 3-carboxylic acid (166 mg; commercial) and intermediate l.iii (200 mg) in NMP (5 ml) was treated with TEA (0.32 ml) and TMSCIijand heated at 85°C for 5 h. The' reaction mixture was evaporated under reduced pressure and the residue was taken up in 5MHC1 in MeOH (3 ml) and stirred for 30 min. The solution was evaporated under reduced pressure and the residue was taken up in EA. The resulting solid was collected by filtration and washed with EA, affording 271 mg (78% yield) of a yellow solid.'. 'HNMR(DMSOd6;6ppm): 0.89-1.27 (4H, tii); 1.78 (2H, d, J = 12.8); 1.90-2.04 (2H. m); 3.53-3.88 (6H, m); 3.88 (2H, s), 4.06 (IH, t, J = 9.0), 4.42 (2H, d broad. J = 13.2), 4.44 (IH, m); 7.11 (2H, m); 7.55 (IH, d, J = 1'4.5); 8.05 (IH, d, J = 13.5); 8.60:(lH,s). ^ MS (ESI): 586.8. '" '' Example 4: 7-(4-{4-[(7?)-5-((ty)-2-amino-propionyloxyniethyl)-2-oxo-oxazolidin-3-yl]-2-fluoro-phenoxymethyl}-4-hydroxy-piperidin-l-yl)-l-cyclopropyl-6-fliioro-4-0X0-1,4-dihydro-quinoline-3-carboxylic acid hydrochloride: 4.i. }-cyclopropyl-6'_fluoro-7-{4-[2~fliwro-4-((R)-54}ydroxymethy}-2-oxo-oxazo]idi}i- 3-y!)-phenoxymethy!]-4-hydroxy-piperi(iin~l-vl}-4-oxO'1.4-dihydro-c]iiiriolirie-- ii 3-carhoxyIic acid betizy! ester: '^ A suspension of intermediate l.iv (300 mg) and K2CO3 (77.8 mg) in DMF (10"ml) was I-treated with BnBr (82 |.d) and stirred at 80°C; for 2 days. The solvents were removed under reduced pressure. The residue was; worked up (DCM) and purified by chromatography (DCM/MeOH 95:5) affording 219 mg (63% yield) of a white powder. 'H NMR (DMS0d6; 6 ppm): 1.0-1.25 (4H, m); 1.71 (2H, dd, J = 0.6 and .].= 12.9): 1.92 (2H, m); 3.25 (2H, m); 3.50 (3H, m); 3.65 (2H, m); 3.78 (lH,dd, J=:6.4 and J = 8.8); 3.89 (2H, s); 4.03 (IH, t, J = 9.1); 4.65 (IH, m); 4.82 (IH. s); 5.17 (IH, t, J = 5.6); 5.25 (2H, s); 7.2] (2H, m); 7.35-7.60 (7Ii m); 7.74 (JH. d, j;=13.5); 8.45 (lH,s). ij MS (ESI): 676.2. || 4.ii. 7-(4-{4-[(R)-5-((S)-2'tert'biitoxycarhoriylamwo-propionyloxyme{hyl)-2-(...^ \\ ()xazoJjdm-S-yI]-2-fliiorO'phe}WxymethyJ}'4-hydroxy-piperidiri'l-yl)-Ucyc}oprqpy]- 6-fJiioro~4-oxo-J,4-dihydro-quinolwe-3-carhoxyIfc acid benzyl ester: I A solution of intermediate 4.i (219 mg) in DMF (3 ml) was treated with Boc-L-Ala-OH (79.7 mg), EDC (81 mg) and DMAP (20 mg).;The reaction was stirred al rl for,2 h. The DMF was evaporated under reduced pressure and the residue was purified by if chromatography (DCM/MeOH 95:5). The relevant fractions were evaporated under reduced pressure and stirred in ether. The solid was collected by filtration affording 280 mg (100% yield) of a white foam. '' 'H NMR (DMSOdfi; 5 ppm): 1.06-1.11 (2H, m); 1.17-1.27 (5H, m); 1.34; (9H, s); 1.67-1.76 (2H, d, J = J2); 1.86-1.99 (2H, m); 3.18-3.25 (2H, m); 3.40-3.50'(2H, m); 3.60-3.72(IH, m); 3.77-3.85 (IH,m,); 3.89 (2H.s); 3.96-4.04 (IH,t, J = 7.3); 4.10 (IH. it t, J = 9); 4.2-43 (IH, dd, J = 4-7 and J=I3.2): 4.38-4.44 (IH, d. i=!1.7); 4.83-4.95 (IH, m); 5.26 (2H, s); 7.20-7.55 (9H, m); 7.75 (lH,d, J = 12.6); 8.46 (IH, s). MS (ESI): 847.5. ■ . '^ -^ 4.Hi. 7-(4-{4-[(R)~5-((S)'2-(ert4mtoxycarhoriylamwo-propioriyhxymethyl)-2-oxb- oxazoh'di}i-3-yl]-2-fliioro~phe?ioxymethyJ}-4-hycfroxV'piperidin~l-yl)-]-cyclopro'pyl- ' i; ' .. " 'I 6-fliioro-4-oxo-l,4-dihvdro-qimioluie-3~carboxvUc acid: ii A solution of intermediate 4.ii (285.3 mg): in dioxane/MeOH, (1:1: 10 ml) was hydrogenated over 10% Pd/C (10 mg) for 4 h; The catalyst was removed by filtration and washed with MeOH (2 ml). The filtrate was evaporated under reduced pressure affording 215 mg (84.4% yield) of yellow foam. ■>. MS (ESI): 757.3. ;i ' \ . ' ! 4.iv. 7-(4-(4-[(R)-5-((S)-2-amino-propiony]oxymethyl)-2'OXo-oxazoUdin-3 yl]-2-fliioro-phenoxymcthyl}-4-hydroxy-piperidir}-l-yJ)-J-cycJopropy}-6-fluoro-4 oxo~l,4-dihydi'o-qninoline~3~carboxy!ic acid hydrochloride: ; A solution of intermediate 4.iii {^193 mg) in dioxane (1 ml) was treated with :0.15 ml HCi (5Min dioxane). The reaction was stirred at rt for 14 h. The soivenl was evaporated under reduced pressure. The residue was taken up in dioxane (10 ml) and the resulting solid was collected by filtration affording 153 mg (86.7%) yield) of a yellow powder. 'H NMR (DMSOdfi; 6 ppm): 1.15-1.33 (4H,.;m); 1.35 (3H. d, J - 6.4);, 1.73; (2H, d, .1= 13); 1.93 (2H, m) ; 3.31 (2H, t, J= II); 3.84 (4H, m);4.l3 (2H, m): 4.35'(IH. dd. J-5 and .1-^12); 4.55 (2H. dd, J = 2 andlLl = 12); 4.95 (IH, m); 7.23 (2H. m); 7.56 (2H, m); 7.88 (IH, d, J - 13.2); 8.51 (2H''SI); 8.64 (IH, s). ; ji MS (ESI): 657.3. i ^ i ■ ^ 'I .1 ' - i" Examples: l-cyclopropyI-6-fluoro-7-{4-I2-fluoro-4-((7?)-2-oxo- -^ 5-phosphonooxyinethyl-oxazolidin-3-yl)-phenoxymethyl]-4-hydi*oxy-piperidin- l-yl}-4-oxo-l,4-dihydro-quinoline-3-carboxylic acid: l! .1 1) 5.i. 7-(4-{4-[(R)-5-(]yis-henzyloxy-pho!iphoryIqxymethyl)-2-oxo-oxazoJidin-3-y]]- 2-Jlii07'o-phenoxymeihyl}-4-hydroxy-piperidin-J-y})-I-cyc}opropyl-6-fliioro-4-oxo- I,4--dihydro-quinoIine-3-carhoxyIic acid: . ; :i , A suspension of intermediate l.iv (300 mg) and 4,5-dicyanoimidazoie (109 mg) in DCM (3 mi) was treated at 0°C with djbenzyl MA^-diisopropyiphosphpramidite ii (0.303 ml). The reaction was stirred at rt for 1 h. A 70%) /er/-butyl hydroperoxide solution in water (0.147 ml) was added. The solution was stirred hh at RT. The solvent ii was evaporated under reduced pressure and The residue was worked up (DCM) and purified by chromatography (DCM/MeOH 95:5), affording 214 mg (49.45 % yield) of an off-white foam. ,i '= I! MS (ESI): 846.3. !; | 5.a. }~cyclopropyl-6-fhioro~7-{4--[2-fh.toro-4-({R)-'2~oxo-5-phosphonooxywethyl-oxazolidm-3-yI)-pherioxymefhyI]-4~hyciroxy-piperidW'J-yl}-4-oxO'1.4-dihydro- j! qiiinolme-3-carhoxyJic acid: ji " [ 1 1^ ■ A solution of intermediate 5.i (214 mg) in AcOH (1.5 ml) was treated with HBr'(l.5 ml; II 33% in AcOH). The reaction mixture was stirred at RT for 2 h and poured into water (20 ml). The gum was stirred for 1 h and decanted. The oily material was taken up in EA (20 ml) and further stirred for 2 h. The solid was collected by filtration and further stirred in DCM (10 ml). The solid was collected by filtration, affording 110 mg (65% yield) of a yellow powder. ;; ^^ ■ 'H NMR (DMSOJ6: 8 ppm): 1.18-1.30 (4V\f m); 1.73 (IH.d. J= 13): l.95i|(2H;m); 2.40 (2H, d. J = 13); 3.26 (2H, m); 3.58 (2H. m); 3.76-3.87 (2H, m); 3.90 (1H,s): 3.95-4.15 (3H, m); 4.47 (IH, s); 4.86 (lH,m); 7.21 (2H, m); 7.57 (2H, m); 7.89i(IH, dd, ij J = 5.9 and J = 13.2); 8.65 (IH, s). !! MS (ES(): 666.2. I ' ^- | i : il , Example 6: l-cyclopropyl-6-fluoro-7-{(/?5)-3-[2-fluoro-4-((i?)-5-hydroxymethyl- ■; fi 2-oxo-oxazolidin-3-yI)-phenoxymethyI]-3-liydroxy-pyrrolidin-l-yl}-4-oxo- ^ l,4-dihydro-quinoline-3-carboxylic acid: ii ,. ,| J ■: ^; \i li 6. i. Diallyl-carhamic acid benzyl ester: i^ :j ■ - r ' Benzoyl chloride (15.5 ml) was added dropwise over 30 min to a solution of ■i diallylamine (12.3 ml) and TEA (21 ml) in DGM (100 ml) at 0 °C. The reaction mixture was stirred at rt for 16 h. The residue obtained after work up (DCM) was purified by chromatography (Hex/EA 95:5) to give 20.71 g (88%' yield) of a colourless liquid. ;; 'H NMR (DMSOd6; 5 ppm): 3.83 (4H, dt, J = l and J = 6); 5.05-5.18 (6H, m); 5.70-5.86 (2H,m); 7.27-7.48 (5H,m). -' ■ -' |j L . 6. a. 2,5-dihydro-pyfrole' J-carhoxylic acid benzyl ester: Benzylidene-bis(tricyclohexylphosphine)dichlororuthenium (5 g) was added to a solution of intermediate 6.i (17.56 g) in DCM (1.5 I) at rt under nitrogen. Thq reaction mixture was stirred at 40 °C for 2 h and concentrated in vacuo. The residue was purified by chromatography (Hex/EA 90:10) to give 14.08 g (91% yield) of a yellow liquid. , 'H NMR (DMSOd6; 5 ppm): 4.05-4.16 (4H,; m); 5.08 (2H. s); 5.81-5.92 (2H. m); 7.27-7.41 (5H, m). I l! ■ li ■ 6. Hi. (RS)-3-hydroxy-pyrrolidine-1 'Carboxylic acid benzyl ester: ,', A \M solution of borane in THF (9 ml) was^added to a solution of intermediate 6.ii (1.81 g) in THF (25 ml) at 0 °C under nitrogen.jThe reaction mixtiu'e was stirredlat it for 16 h and was cooled to 0 °C. 20% NaOH (1.8 ml) was carefully added dropwise followed by 35% aq. hydrogen peroxide (1.2 ml). The mixture was stirred at 0 °C for 30 min and at rt for 2 h. Et20 and an aq. 40% sodium bisulfite solution were added and the reaction mixture stirred vigorously for 15 min. The residue obtained after )Vork up (Et20) was purified by chromatography (Hex/EA 5:5 to 3:7) to give 1.01 g (51% yield) of a colourless oil. ' ; ' 'H NMR (DMS0d6; 5 ppm): 1.67-1.82 (IH, n{); 1.82-].96 (IH. m); 3.16-3.25 f)H. m); 3.28-3.44 (3H, m); 4.20-4.29 (IH, broad); 4.92 (IH, d, J = 3); 5.06 (2H, s); 7.27-7.41 (5H, m). . ' '! : i 6. iv. 3-oxO'pyrrolidir)e-}-carboxylic acid benzyl esler: '| A solution of intermediate 6.iii (1.10 g) in DCM (8 ml) was cooled to 0 *^C and DIPEA (2.5 ml) was added dropwise, followed by a solution of sulfur trioxide pyridine complex (1,79 g) in DMSO (6.5 ml). The reaction mixture was stirred at 0 °C for 1 h'and was quenched by the addition of water (6 m\). The aq. layer was exUacted with ElzO/Ilex (1:1,3 X 5 ml) and the combined org. layers were concentrated in vacuo. Th^ residue obtained after work up (Et20/Hex 1:1) was purified by chromatography (Hex/EA 5:5) to give 1.05 g (96% yield) of a yellowish oil. ' 'H NMR (DMSOd6; 5 ppm): 2.48-2.61 (2H', m); 3.61-3.80 (4H, m): 5.09^(2H, s): 7.27-7.41 (5H.m). [ 6.V. S-methylene-pyrrolidine-l-carboxylic acid benzyl ester: i /-BuOK (617 mg) was added in one portion to a white suspension of methyl triphenylphosphonium bromide (1.98 g) in THF (10 ml) at rt under nitrogen. The yellow suspension was stirred at rt for 1 h and -then cooled to -10 X. A solution of intermediate 6.iv (1.05 g) in THF (2 ml) was added dropwise over 10 min and the reaction mixture was allowed to warm to rt over 2 h. The reaction was quenched by the addition of sat. aq. NH4CI (! ml) and diluted with EA, The residue obtained after work up (EA) was purified by chromatography (Hex/EA 90:10) to give 633 mg (64% yield) of a yellowish liquid. 'l-I NMR (DMS0d6; 5 ppm): 2.48-2.61 (2H, m); 3.36-3.53 (2H. m); 3.84-4.01 (2H, m): 4.97-5.03 (2H, m); 5.08 (2H, s); 7.27-7.41 (5H, m). 6. vi. J -oxa~5-aza-spiro[2.4]heplane~5-carhoxylic acid benzyl ester: A solution of intermediate 6.v (7.21 g) in DCM (400 ml) was treated with MCPBA (20.1 g) and NaHCOa (22.3 g) at rt. The reaction was stirred at rt for 2 h, diluted with DCM (200 ml) and poured in a solution of Na2S03 (45 g) in water (400 ml). The mixture was stirred for 10 min and the org. layer was separated. The residue obtained after work up (DCM) was purified by chromatography (Hex/EA 6:4) to give 4.37 g (56% yield) of a yellow oil. 'H NMR{DMS0d6; 5 ppm): 1.70-1.83 (!H, m); 2.22-2.37 (IH. m); 2.90-2.94 (J H. m); 2.95-2.99 (IH, m); 3.15 (IH, t, .1 = 11); 3.39-3.77 (3H, m); 5.09 (2H, s); 7.27-7.41 (5H, m). 6.vii. (RS)-3-[2'jliiorO'4-((R)-5-hydroxymethyl-2-oxo~oy:azolidW'3-yl)-phenoxymethy]]' S-hydmxy-pyrroHdine-1-carboxylic acid benzyl ester: ■■ ,. K2CO3 (274 mg) was added to a suspension of intermediate l.i (300 mg) and intermediate 6.vi (338 mg) in DMF (3 ml). The reaction mixture was stirred at 80 °C for 3 h and the solvent was removed in vacuo. The residue obtained after work up (DCM) was purified by chromatography (DCM/MeOH 95:5) to give 531 mg (87% yield) of a beige foam. 'H NMR (DMSOdrt; 5 ppm): 1.80-1.92 (IR m); J.96-2.08 (IH, m); 3.32-3.59,(5H. m); 3.66 (IH, ddd, J = 3, J = 6 and J =13); 3.80 (IH, dd, J = 6 and J - 9);-3.97-4.09 (3H. m); 4.64-4.72 (IH, m); 5.07 (2H, s); 5.19 (IH, t, J = 6); 5.23 (IH, s); 7.18-7.23 (2H. m): 7.27-7.38 (5H, m); 7.57 (IH, dd, J = 2 and J = 14). MS (ESI): 460.9. 6.viii. (R)-3-[S-fli{oro-4-((RS)-3-hydroxy-pyrroUdin-3-yimethoxy)-phenyI]-S-hydroxymethyJ-oxazoUdin-l-one: A solution of intermediate 6.vii (259 mg) in THF/MeOH (1:1; 20 ml) was hydrogenated over 10% Pd/C (60 mg) for 20 h at n. The reaction mixture was concentrated //? vacuo. taken in DCM/MeOH 90:10 (20 ml) and stirred at rt for 30 min. The catalyst was filtered off and the filtrate concentrated in vacuo to give 184 mg (100% yield) of an orange foam. MS (ESI): 327.3. 6.ix. l-cyc}opropy}-6-f!uoro-7-{(RS)-3'[2'fliioro-4-((R)-5-hydroxymethyl-2'OXO' oxazo}i£Jin~3-y])-phe}wxyme}hyl]-3-hydroxy-pyrroJidw~l-y]}-4-oxo-} ,4 dihydro-cpnnoUne-3-carboxylic acid: A solution of intermediate 6.v((i (226 mg) and 7-chloro-l-cyclopropyl-6-fIuoro-K4-dihydro-4-oxo-3-quinolinecarboxylic acid boron diacetate complex (270 mg; prepared according to WO 88/07998) in NMP (5 ml) was treated with DIPEA (120 ^1) and stirred at 60 °C for 2 h. The reaction mixture was concentrated in vacuo and the residue was taken in 5A'/ HCI in MeOH (2 ml). The solution was stirred at rt:for 1 h. concentrated in vacuo and the residue was purified by chromatography (DCM/MeOH/AcOH 95:4:1 to 90:9:t). The foamy residue was taken in MeOH (2 ml), stirred for I h and filtered. The crystals were collected and dried in vacuo to afford 23 mg (6%) yield) of a beige solid. 'H NMR (DMSOdf,; 5 ppm): 1.10-1.34 (4H, m); 1.98-2.10 (IH, m); 2.14-2.26 (IH, m); 3.48-3.70 (3H, m); 3.71-3.89 (5H. in); 4.05 (IH, t, J - 9); 4.09-4.18 (2H, m); 4.66-4.74 (IH,m); 5.19 (IH, t, J - 6); 5.40 (IH, s); 7.09 (IH, d. J = 8); 7.18-7.31 (2H. m);7.59(iH,dd, J-2and J - 14); 7.82 (IH, d, J = 14); 8.59 (IH. si; 15.52 t.Ill, s). MS (ESJ): 572.3. Example 7: l-cyclopropyl-6-fluoro-7-{(^4S)-3-(2-fluoro-4-((J?)-5-hydroxymethyl-2-oxo-oxazolidin-3-yI)-phenoxymcthyIl-3-hydroxy-pyrrolidin-l-yl}-8-methoxy-4-0X0-1,4-dihydro-quinoline-3-carboxylic acid: This compound was obtained as a yellow solid in 52%o yield, starting from intermediate 6.viii (85 mg), l-cyclopropy!-6,7-difluoro-l,4-dihydro-8-methoxy-4-oxo-3-quinolinecarboxylic acid boron diacetate complex (100 mg; prepared according to Sakurai et al., Bioorg. Med Chew. Left. (1998), 8, 2185-2190) and DIPEA (43 |al) and 36 following the procedure of Example 6, step 6.ix. The foamy residue was stirred m EA (5 ij ml) and dried. i ■' !i : T . MS (ESI): 602.2. ;; i' . Examples: l-cyclopropyl-6-fliioro-7-{(ff5')-3-[2-fluoro-4-((/f)-5-hydroxymethyl-2-oxo-oxazolidin-3-yl)-phenoxyniefhyl]-pyrroIidin-l-yl}-4-oxo-l,4-dihydro- j i - quinolinc-3-carboxylic acid: li ■ i 8. i. (RS}-3-hydroxymethyl~pyr}'o)Jdme-l-carhoky]ic acid henzyl ester: i I This compound was obtained as a colourless oil in 68% yield, starting from interiiTiediate 6.V (630 mg) and a IM solution of borane in THF (9 ml), and following the procedure of Example 6, step 6.iii. \ \ . 'l-I NMR (DMSOd6; 5 ppm): I.5I-T71 (IH, m); 1.79-1.97 (IH, m); 2.19-2.35 (IH, m); 3.00-3.15 (IH, m); 3.19-3.50 (5H, m);|4.65 (JH, t, J = 5); 5.05 (2H, s); 7.27-7.40 (5H. m). ■' MS (ESI): 235.9. \ . ' SM. ('RS)-3-{4-[{R)-5-{terl-hiftyI--dimethvl~-siIanyIoxyr}iethyl)-2-oxo-oxazo/idiri-3--y/J- 2-fliioro-phenoxymethyl}-pyrrolidine-1-carhoxyUc acid henzyl ester: ii A suspension of intermediate 8.i (456 mg)' intermediate 2.ii (630 mg) and PPhs (726 mg) in THF (8 ml) was treated dropwise^over 2 h with DIAD (0.55 ml) at it. The reaction mixture was further stirred at rt for 2 h and was concentrated in vacuo. The residue was purified by chromatography (Hex/EA 7:? to 6:4) to give 966 mg (94% yield) of a yellow oil. , l| 'H NMR (DMSOd6; 6 ppm): 0.04 (6H, L); 0.79 (9H, s); 1.65-1.82 (iH, m); 1.93-2.08 (IH, m); 2.56-2.74 (IH, m); 3.14-3.25 (IH, m); 3.30-3.59 (3H, m); 3.69-3.78 (IH, m); 3.74 (IH, dd, J = 3 and J = 12); 3.87 (IH, dd, J = 3 and'J = 12); 3.95-4.12 (3H, ,m); 4.70-4.83 (IH, m); 5J05-5.08 (2H, m); .7.16-7.21 (2H. m); 7.27-7.38 (5H, m); 7.56 (IH, dd, J = 2 and J =;14). ^ '' MS (ESI): 559.3. f > ^ 8.Hi. (RS)-3-[2-fluoro-4-((R)-5-hydroxymethy}-2-oxo-oxazolidin-3-y1)-pher}Oxymelhyl]- pyrroUdine-1-carboxylic acid benzyl ester: '^ . \ ■ A solution of intermediate 8.ii (200 mg) in didxane (1 ml) was treated with 6MHC1 in dioxane (0.30 ml) at rt. The reaction mixture was stirred at rt for 2 h and concentrated to dryness. The residue was diluted in DCM, washed with sat. aq. NaHCO? and worked up (DCM). The crude product was purified by FC (DCM/MeOH 98:2 to 96:4)': to eive 258 mg (81% yield) of a yellowish oil. i I 'H NMR (DMSOd6; 5 ppm): I.66-I.82 (iH, m); I.96-2.I0 (IH, m); 2.58-2.74 (iH, m); 3.14-3.26 (IH, m); 3.28-3.38 (IH, m); 3.39-3;61 (3H, m); 3.66 (IH, ddd, J =^4, .1 = 6 and J-13); 3.80 (IH, dd, J-6 and J = 9);'b.94-4.08 (3H, m); 4.62-4.71 (;1H, m); ■L 5.05 (2H, s); 5.19 (IH, t, .1 = 6); 7.18-7.21 (2H. m); 7.27-7.38 (5H. m); 7.57 (IH. dd. .! = 2andJ = 14). ; MS (ESI): 445.2. '; , '■ ■ 8.iv. (R)-3-[3-JIiioro-4-{{RS)-J-pyrro!i(iiri~3'yh7wthoxy)-pheny!J-5'hydroxyme!hyl- oxazoh'din-2-one: ,5 ., i) This compound was prepared in 100%o yield] as a pinkish solid by hydrogenation of ' .i intermediate S.iii (230 mg) over 10%) Pd/C (72 mg) following the procedure of Example 6, step 6.viii. ', ^ MS (ESI): 311.3. i| ;* :: 8.V. }-cycJopropyl-6-JliiorO'7~{(RS)-3-[2-jliioro-4-((R)-5-hydroxyTnethyl-2-oxo- oxazolidm-3-y])-phe}ioxymethyl]-pyrrolidm'-}-y]}-4-oxo-},4-dihydro-qiimoUne^.. 3-carhoxylic acid: '; :: ii Tliis compound was prepared in 17% yield as a yellow solid, starting from intermediate 8.iv (67 mg), 7-chloro-I~cyclopropyl-6-fluoro-l,4-dihydro-4-oxo- I 3-quinolinecarboxylic acid boron diacetate complex (80 mg; prepared according to WO 88/07998) and DIPEA (36 fil), and following the procedure of Example 6, step 6.ix. The crude product was purified by chromatography (DCM/MeOH/AcOH 98:1:1 to 94:5:1) and the foamy residue was stirred in MeOH (1 ml). ;< 'HNMR(DMSOd6;5ppm): 1.10-1.34 (4H. m); 1.85-2.01 (IH, m); 2.14-2.28;(1H. m); 2.75-2.90 (IH, m); 3.48-3.60 (2a m); 3J60-3.88 (6H. m); 4.05 (IH, t. J = 9): 4.09-4.18 (2H, m); 4.63-4.72 (IH, m); 5.19 (IH, t, J = 6); 7.09 (IH. d, J = 8); 7.18-7.29 (2H, m); 7.58 (IH, dd, '-^ ""'' .'^1^^. i on r^j A T = I/IV C ^C nw .^-14.48 (lH,s). MS (ESI): 556.3. Example 9: l-cycIopropyl-6-fluoro-7-{(i?^-3-[2-nuoro-4-((/?)-5-hydroxymethyl-2-oxo-oxazolidin-3-yI)-phenoxymethyI]-pyrrolidin-l-yl}-8-methoxy-4-oxo-l,4-dihydro-quinoUne-3-carboxylic acid: This compound was obtained as a yellow solid in 12% yield, starting from intermediate 8.iv (65 mg), ]-cyclopropyI-6,7-dif]i]oro-],4-dihydro-8-methoxy-4-oxo-3-quinolinecarboxyiic acid boron diacetate complex (80 mg; prepared according to Sakurai et al., Bioorg. Med Chem. Lett. (1998), 8, 2185-2190) and DIPEA (27 \xX) and following the procedure of Example 6, step 6.ix. The crude product was purified by chromatography (DCM/MeOH/AcOH 98:1:1 to 94:5:1) and the foamy residue was stirred in EA/Et20(2:l; 1.5 ml). 'H NMR (DMSOds; 5 ppm): 0.90-1.18 (4H, m); I.76-I.93 (IH, m); 2.10-2.24 (IH, m); 2.70-2.81 (IH, m); 3.57 (3R s); 3.56-3.83 (7H, m); 3.99-4.20 (4H, m); 4.62-4.73 (IH, m); 5.19 (IH, t, J - 6); 7.18-7.29 (2H- m); 7.58 (IH, ddJ = 3 and J = 14); 7.68 (IH, d, J = 14):8.64(tRs); 15.13 (IH.s). MS (ESI): 586.3. Example 10: I-cyclopropyl-6-fluoro-7-{4-f2-f1uoro-4-((i?)-5-hydroxymefhyi-2-oxo-oxazolidin-3-yl)-phenoxymethyI]-4-phosphonooxy-piperidin-l-yl}-4-oxo-l,4-dihydro-quinoline-3-carboxylic acid: lO.i. 7-{4-{4-[5-(tert-butyl-dimethyl-silar}ylox}mieth)d)'2-oxO'OxazoUdiri-S-ylJ'^2-fJuoro-phenoxymethyJ}-4-hydroxy-piperidm-}'yl)-}-cyclopropyl'6-fluoro-4-oxo-l,4-dihydro-qu/fioIwe-3-carboxyIic acid benzyl ester: Imidazole (67 mg) and TBDMSCl (162 mg) were added to a solution of intermediate 4.i (600 mg) in DMF (6 mJ). The solution was stirred at rt for 6 h. The solvent was evaporated under reduced pressure and the residue was worked up (DCM) and purified by chromatography (DCM/MeOH; 95:5), affording 544 mg (75.6% yield) of a yellow solid. 'H NMR (DMSOde; 5 ppm): 0.03 (6H, s); 0.78 (9H, s); 1.10 (2H, m); 1.22 (2H, m); 1.70 (2H. m); 1.92 (2H, m); 3.2 (2H, m); 3.45 (2H, m); 3.70 (3H, m): 3.83-3.88 (1H, dd. J = 2.6 and J = 12); 3.89-(2H, s); 4.07 (IH, t, J = 9); 4.73 (IH, m); 4.82 (IH, s); 5.26 (2H, s); 7.20 (2H, m); 7.28-7.58 (7H, m); 7.75 (IH, d, J = 13.5); 8.46 (1H, s). MS (ESI): 790.5. 10.a. 7-(4~(bis-benzyJoxy-pho.? vacuo to give 35 mg (34% yield) of a yellow solid. 'HNMR(DMSOd6;6ppm): 1.62-1.92 (4R m); 3.41-3.60 (3H, m); 3.60-3.69 (IH, m); 3.78 (IH, dd, J = 6 and J = 9); 3.86 (2H, s); 4.02 (IH, t, J = 8); 4.22-4.37 (2H, m); 4.60-4.72 (IH, m); 4.95 (IH, broad); 5.18 (IH, broad); 7.13-7.23 (2H. m); 7.50-7.59 (IH, m); 8.01 (IH, d, J = 14); 8.79 (IH, broad); 13.26 (IH, broad): 15.34 (IH, broad). MS (ESI): 547.3. BIOLOGICAL ASSAYS In vitro assay Experimental methods: ■< l] These assays have been performed following the description given in "Methods for dilution Antimicrobial Susceptibility Tests for Bacteria that Grow Aerobically, 4th ed.; Approved standard: NCCLS Document M7-A4; National Committee for Clinical Laboratory Standards: Villanova, PA, USA, 1997". Minimal inhibitory concentrations (MlCs; mg/1) were determined in cation-adjusted Mueller-Hinton Broth (BBL) by a microdilution method following NCCLS guidelines (National Committee for Clinical Laboratory Standards. Methods for Dilution Antimicrobial Susceptibility). 1 he pH of the test medium was 7.2-7.3. In the particular case wherein the compound to be tested is a compound of formula IPDG wherein at least one of R' and R^ represents OPO3H2, then the test was carried out in the presence of human alkaline phosphatase (concentration: 1 U/ml). In the particular case wherein the compound to be tested is a compound of formula IPDG wherein R' represents a group OCOR^, then the test may be carried out in the presence of 50% human serum. However, this was not needed for the compounds of Examples 4 and 12 that already showed significant activity in the absence of human serum. Results: Ail the above Examples were tested against several Gram positive and Gram negative bacteria. Typical antibacterial spectra are given in the table below (MIC in mg/1). Example No. S. aureus A798 S. Pneumoniae 49619 M, caiarrhalis A894 3 0.25 0.125 0.5 7 1 0.25 0.063 Besides, the following results have been obtained for the Example compounds corresponding to formula ID on S. aureus A798 (MIC in mg/I): Example No. S. aureus A798 Example No. 5". aureus A798 1 0.25 8 0.125 2 0.25 9 I 3 0.25 n > 16 6 1 13 2 7 1 H 4 In addition, the compound of Example 11 has a MIC of 8 mg/1 against E.faecalis 29212 bacteria. Moreover, in physiological environment (comprising phosphatases and esterases), the compounds of formula IPDG are rapidly converted into the corresponding compounds of formula ID. Indeed: the compounds of Examples 5 and 10, in the presence of human alkaline phosphatase, have MICs of respectively 0.25 and 0.5 mg/I against S. aiireus A798, whereas the same compounds have MICS of respectively > 16 mg/1 and 16 mg/1 against S. aureus A798 when the phosphatase is absent; and the compounds of Examples 4 and 12, even in the absence of human serum, each have a MIC of 0.5 mg/1 against 5. aureus A798. We Claim: 1. A compound of the formula 1 or a salt of such a compound. 2. A compound of formula I according to claim 1, wherein n is 0; or a salt of such a compound. 3. A compound of formula 1 according to claim I, wherein n is I; or a salt of such a compound. 4. A compound of formula 1 according to claim I, wherein A is representing H or alkoxy; ■ or a salt oT sucn a compouna. 5. A compound of fon-nula I according io ciaim 1. wherein R"' is fluorine: or a salt of such a compound. 6. A compound of formula i according to claim 1. wherein R" is cycloalkyl; or a salt of such a compound. 7. A compound according to claim 1, which is selected from the following: - l-cycIopropyl-6-nuoro-7-{4-|2-fluoro-4-((i?)-5-hydroxymethyl-2-oxo-oxazolidin-3-yl)-phenoxymethyl]-4-hydroxy-piperidin-l-yi}-4-oxo-!,4-dihydro-quinoline-3-carboxy!ic acid: - l-cyc!opropyl-6-fluoro-7-{4-[2-fluoro-4-((/?)-5-hydroxymethyi-2-oxo-oxazoiidin-3-yl)-phenoxymethyl]-piperidin-l-yl}-4-oxo-1.4-dihydro-quinoline-3-carboxylic acid: - Ncyclopropyl-6-fluoro-7-{4-[2-fluoro-4-({R)-5-hydroxymethyl-2-oxo-oxazoiidin-3-yl)-phenoxymethyl]-4-hydroxy-piperidin-i-yl 1-4-0X0-1.4-dihydro-[l,8]naphthyridine-3-carboxylic acid; - 7-(4-{4-[(i?)-5-({5)-2-amino-propionyloxymethyl)-2-oxo-oxazolidin-3-yl]-2-f!uoro-phenoxymethyl}-4-hydroxy-piperidin-l-yl)-l-cyclopropyl-6-fluoro-4-oxo-I.4-dihydro-quinoline-3-carboxylic acid; - l-cyc!opropyl-6-fluoro-7-{4-[2-fiuoro-4-((;?)-2-oxo-5-phosphonooxymethyl-oxazolidin-3-yl)-phenoxymethyl]-4-hydroxy-piperidin-l-yl}-4-oxo-l,4-dihydro- quinoline-3-carboxylic acid; r - l-cyclopropy!-6-fluoro-7-{(7?)-?-[2-f1uoro-4-((/?)-5-hydroxymethyl-2-oxn-nxa7olidin-3-yl)-phenoxymethyl]-3-hydroxy-pyrroiidin-l-yl}-4-oxo-l,4-dihydro-quinoline-3-carboxylic acid; - l-cyclopropyl-6-fluoro-7-{(5)-3-[2-fIuoro-4-({i^)-5-hydroxymethyl-2-oxo-oxazoiidin-3-yi)-phenoxymethyl]-3-hydroxy-pyrrolidin-l-yl}-4-oxo-l,4-dihydro-quinoline- 3-carboxylic acid; - l-cyciopropyI-6-fluoro-7-{(7?)-3-[2-fluoro-4-({i?)-5-hydroxymethyl-2-oxo-oxazoiidin- 3-yl)-phenoxymethyl]-3-hydroxy-pyrrolidin-I-vll-8-methoxv-4-oxo-1.4-dihydro- quinoline-3-carboxylic acid; - l-cyclopropyl-6-fiuoro-7-{{5)-3-[2-fluoro-4-((A)-5-hydroxymetiiyl-2-oxo-oxazo!idin-3-yl)-phenoxymethyi]-3-hydroxy-pyrrolidin-l-yl}-8-methoxy-4-oxo-l,4-dihydro-quinoline-3-carboxylic acid; - l-cyclopropyl-6-fluoro-7-{(7?)-3-[2-fluoro-4-((y?)-5-hydroxymethyl-2~oxo-oxazolidiiv 3-yI)-phenoxymethyl]-pyrrolidin-l-yi)-4-0x0-K4-dihydro-quinoline-3-carboxyiic acid; - l-cyclopropyl-6-fluoro-7-((iS)-3-[2-f!uoro-4-((i?)-5-hydroxymethyl-2-oxo-oxazolidin~ 3-yi)-phenoxymethy!]-pyrrolidin-l-yl}-4-0X0-i,4-dihydro-quinoline-3-carboxylic acid; - l-cyclopropyl-6-fluoro-7-{(7?)-3-[2-fluoro-4-((i?)-5-hydroxymethy!-2-oxo-oxazolidin- 3-y))-phenoxymethyl]-pyrrolidin-)-yl}-8-methoxy-4-0X0-1,4-dihydro-quinoline- '! 3-carboxy!ic acid; - I-cyciopropyI-6-fluoro-7-((6)-3-[2-fluoro-4-((i?)-5-hydroxymethyl-2-oxo-oxazoiidin-3-yl)-plienoxymethyl]~pyrrolidin-l-yi}-8-methoxy-4-oxo-K4-dihydro-quinoline-3-carboxylic acid; - l-cyclopropyl-6-fluoro-7-{4-[2-fluoro-4-{(/?)-5-hydroxymethyl-2-oxo-oxazolidin-3-yl)-phenoxymethyI]-4-phosplionooxy-piperid in-1-yl}-4-0X0-1,4-dihydro-quinoline-3-carboxylic acid; - l-ethyl-6-fIuoro-7-{4-[2-fluoro-4-((7?)-5-hydroxymethyl-2-oxo-oxazo!idin-3-yI)-phenoxymethy!]-piperidin-l-yI}-4-oxo-l,4-dihydro-quinoline-3-carboxylic acid; - 7-(4-(4-[(^)-5-((5)-2-amino-propionyloxymethy!)-2-oxo-oxazolidin-3-yl]-2-fluoro-piienoxymethyl}-piperidin-l-yi)-l-cyclopropyl-6-fluoro-4-oxo-l,4-dihydro-quinoline-3-carboxylic acid; , - 6-fluoro-7-{4-[2-f]uoro-4-((;?)-5-hydroxymethy]-2-oxo-oxazolidin-3-yl)-phenoxymemyi]-4-hydroxy-piperidin-l-yi)-4-uxo-L4-dihydru-quino!inco-caibox>'lic acid; -6-fluoro-7-{4-[2-fluoro-4-((i?)-5-hydroxymethyl-2-oxo-oxazolidin-3-yI)- phenoxymethyI]-4-hydroxy-piperidin-1 -y!}-4-oxo-1,4-dihydro-[ i ,8]naphthyridine- 3-carboxylic acid; or a pharmaceuticaliy acceptable salt of such a compound. 8. As a medicament, a compound of formula I as defined in claim K or a pharmaceuticaliy acceptable salt thereof. 9. A pharmaceutical composition containing, as active principle, a compound of formula ! as defined in claim 1 or a pharmaceutically acceptable salt thereof, and at least one therapeutically inert excipient. 10. Use of a compound of formula 1 as defined in claim 1. or of a pharmaceutically acceptable salt thereof, for the manufacture of a medicament intended for the prevention or treatment of bacterial infections.