The present invention relates to cyclohexane compounds according to general formula (I) and pharmaceutical compositions comprising compounds according to general formula (I). In particular, the present invention relates to the use of the compounds for the treatment of a bacterial infection, particularly for use as an antibiotic.

Since the discovery of antibiotic substances and their use against microbes, bacteria have evolved to defend themselves by acquiring resistances. Especially in hospitals where bacteria are exposed to a wide array of antibacterial substances, strains arose that are multiresistant. A prominent example for this is the multiresistant Staphylococcus aureus (MRSA) against which vancomycin used to be a reliable cure, until the strains Vancomycin-Intermediate/Resistant Staphylococcus aureus (VISA / VRSA) started to appear, which are also resistant against this last defence.

The mechanisms of resistance are usually tightly intertwined with the mode of action of the antibiotic. Therefore, the resistance against one representative of a certain antibiotics class yields to resistance against the entire group with the same mode of action. This is why it is not only necessary to have an ongoing search for new antibiotic substances, but to also find and use new antibacterial targets enforcing new mechanisms of action.

In the past the mode of action for several antibacterial compounds was revealed to be inter alia the targeting of riboswitches. To date metabolite analogues have been described which modulate thiamine pyrophosphate (TPP), lysine, flavin mononucleotide (FMN) or purine riboswitches. Riboswitches have appeared as one of these new promising targets for antibacterial defence.

Riboswitches, which regulate 2-4% of all bacterial genes, are found in the 5 '-untranslated region (5' UTR) of bacterial mRNA and consist of an aptamer and an expression domain. Upon metabolite binding, a change in secondary structure leads to termination of transcription or inhibition of translation initiation. Amongst them the glmS riboswitch (glucosamine-6-phosphate synthetase riboswitch) which is predicted to exist in at least 18 Gram-positive organisms has an exceptional mechanism of regulation. The glmS riboswitch binds glucosamine-6-phosphate to regulate glucosamine-6-phosphate synthetase (glmS) genes. Once glucosamine-6-phosphate binds, this riboswitch acts as a ribozyme, resulting in cleavage of the 5' end of the riboswitch.

Antibiotic resistance creates a permanent need for new antibacterial targets. Thus, it would be desirable to provide compounds that target the glmS riboswitch and exhibit antimicrobial activity.

Therefore, the object underlying the present invention was to provide compounds that are usable as antibiotic.

The problem is solved by a compound according to general formula (I) as given as follows and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof:

wherein:

R ^J is selected from the group comprising H, OH, SH and/or NH ₂ ;

R ² is selected from the group comprising hydrogen, Ci-Cio-alkyl, C ₇ -Ci ₄ -arylalkyl wherein the aryl group has 6 to 10 carbon atoms and the alkyl group has 1 to 4 carbon atoms,

,-alkyl, OC(O)C ₁ -C ₁₀ -alkyl, C(O)OC ₁ -C ₁₀ -alkyl, C(0)NH ₂ , NH ₂ and/or R ³ is selected from the group comprising OH, SH and/or NH ₂ ;

R ⁴ is selected from the group comprising OH, SH and/or NH ₂ ;

R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ , S(0) ₂ OH, P(S)(OH) ₂ ,

P 0)OHSH, S(0) ₂ SH and/or aryloxy phosphoramidates according to general formula (II)

wherein:

R ⁶ is selected from the group comprising linear or branched Ci-C ₆ -alkyl, benzyl and/or cyclohexyl;

R ⁷ is a side chain of an amino acid selected from the group comprising hydrogen; linear or branched Ci-C ₄ -alkyl; linear or branched alkyl groups of the type -C _n H _2n -U-D wherein n is 1, 2, 3 or 4, U is selected from the group comprising O, CO, COO, CONH, S, guanidine and/or NH and D is selected from the group comprising H and/or Ci-C ₃ -alkyl; -CH ₂ -C ₆ H ₄ -Y wherein Y is selected from the group comprising OH, SH, Ci-C ₃ -alkyl and/or NH ₂ ; -CH ₂ -imidazole; -CH ₂ -indole; -CH ₂ -(furanyl-3-yl); -CH ₂ - (pyridyl-3 -yl) and/or -CH ₂ -(imidazolyl-3 -yl) ;

X is selected from the group comprising CI, Br, I, Ci-C ₆ -alkyl and/or Ci-C ₆ -alkoxy;

8 8 9 8 9

A is selected from the group comprising S, NR , C=CR°R ^* and/or CR°R', wherein

R ⁸ , R ⁹ is selected, the same or each independently of the other, from the group comprising hydrogen, Ci-Cio-alkyl, C ₂ -Ci ₀ -alkenyl, C ₆ -Ci ₀ -aryl, C ₇ -Ci ₄ -arylalkyl wherein the aryl group has 6 to 10 carbon atoms and the alkyl group has 1 to 4 carbon atoms, C(0)Ci-Cio-alkyl, C(O)OCi-Ci ₀ -alkyl, C(0)NH ₂ , NH ₂ , S(0) ₂ OH and/or a linker.

Furthermore, the invention relates to a pharmaceutical composition comprising a compound according to the invention as an active ingredient, the use of a compound according to the invention in the treatment of a bacterial infection and a method for preparing such compounds. Preferred embodiments of compounds are given in the dependant claims. Su risingly it was found that a compound according to the invention can exhibit an affinity to the glmS riboswitch (glucosamine-6-phosphate synthetase riboswitch) and is able to activate the glmS riboswitch. Beneficially, the compounds according to the invention can be useful as an antibacterial substance in the treatment of bacterial infection. The present invention therefore provides a novel approach to the treatment of bacterial infection.

The term "alkyl" according to the invention is to be understood as meaning straight-chain or branched alkyl groups. The term "Ci-Cio-alkyl" as used herein refers to straight-chain or branched alkyl groups having 1 to 10 carbon atoms. Preferred Ci-Cio-alkyl groups are selected from the group comprising methyl, ethyl and the isomers of propyl, butyl, pentyl, hexyl, heptyl or octyl, such as, for example, isopropyl, isobutyl, tert.-butyl, sec. -butyl and/or isopentyl. Especially preferred are Ci-C ₅ -alkyl groups selected from the group comprising methyl, ethyl and/or isopropyl. The term "alkenyl" according to the invention is to be understood as meaning straight-chain or branched alkyl groups having at least one or several double bonds. The term "C ₂ -Ci ₀ -alkenyl" as used herein refers to straight-chain or branched alkenyl groups having 2 to 10 carbon atoms and at least one or several double bonds. Preferred C ₂ -Ci ₀ -alkenyl groups are selected from the group comprising ethylen-l-yl, propen-l-yl, allyl, buten-l-yl, buten-2-yl and/or buten-3-yl.

The term "C ₆ -Ci ₀ -aryl" according to the invention is to be understood as meaning aromatic groups having 6 to 10 carbon atoms. Preferably, the term "C ₆ -Ci ₀ -aryl" refers to carbocycles. Preferred C ₆ - Cio-aryl is selected from the group comprising phenyl or naphthyl. The term "arylalkyl" according to the invention unless specifically stated otherwise is to be understood as meaning a group which bonds by the respective last-mentioned group, referring to "arylalkyl" by the alkyl group.

The term "C ₇ -Ci ₄ -arylalkyl wherein the aryl group has 6 to 10 carbon atoms and the alkyl group has 1 to 4 carbon atoms" preferably is a group phenylalkyl wherein the alkyl has 1 to 4 carbon atoms, more preferably selected from the group comprising benzyl, phenylethyl and/or phenylbutyl.

The term "alkyloxy" according to the invention is to be understood as meaning an alkyl group connected to the oxy connecting atom unless specifically stated otherwise. The term "Ci-C ₆ -alkyloxy" as used herein refers to an alkyloxy group having 1 to 6 carbon atoms. Ci-C ₆ -alkyloxy groups are preferably selected from the group comprising methoxy, ethoxy, n-propoxy, isopropoxy and/or butoxy.

The term "amino acid" according to the invention is to be understood as meaning alpha amino acids, molecules containing both amine and carboxyl functional groups attached to the same carbon, which is called the alpha-carbon. The term "amino acid" according to the invention is to be understood as being broadly defined to include any modified and unusual amino acid. Preferred amino acids are naturally occurring amino acids. Representative amino acids include, but are not limited to, the group comprising glycine, alanine, serine, threonine, arginine, lysine, aspartic acid, glutamic acid, asparagine, glutamine, phenylalanine, tyrosine, tryptophan, leucine, valine, isoleucine, cysteine, methionine, histidine and/or proline. The various alpha amino acids differ in which side chain is attached to their alpha carbon.

The term "side chains of amino acids" according to the invention is to be understood as meaning the groups attached to the alpha carbon of alpha-amino acids. For example the side chains of glycine, alanine, valine, leucine and phenylalanine are hydrogen, methyl, iso-propyl, isobutyl and benzyl, respectively.

Preferably, the substituent A is selected from the group comprising S, NR ⁸ and/or CR ⁸ R ⁹ , wherein R ⁸ and R ⁹ are selected, the same or each independently of the other, from the group comprising hydrogen, Ci-C ₅ -alkyl, C ₆ -Ci ₀ -aryl, or C ₂ -C ₅ -alkenyl.

In a preferred embodiment, the element A is a group -CH ₂ - and the compound has the formula (III) as indicated below and/or racemates, enantiomers, diastereomers, solvates, hydrates, and

pharmaceutically acceptable salts and/or esters thereof:

Advantageously, the compound according to the formula (III) can exhibit a good affinity to the glmS riboswitch and can be particularly useful as an antibacterial substance in the treatment of bacterial infection.

Preferably, the substituent R ¹ is a hydroxyl group. Further, the substituent R ¹ can be hydrogen. Further preferred, the substituent R ³ is a hydroxyl group. Further preferred, the substituent R ⁴ is a hydroxyl group. In a preferred embodiment of the compound according to the invention the substituents R ¹ , R ³ and R ⁴ are OH. In another preferred embodiment of the compound according to the invention the substituent R ¹ is hydrogen and the substituents R ³ and R ⁴ are OH.

Advantageously, the substituents R ¹ , R ³ and R ⁴ being a hydroxyl group can result in a substantial increase in activation of the glmS riboswitch by the compounds according to the invention.

In a preferred embodiment, the substituent R ² is selected from the group comprising hydrogen, Ci-C ₅ - alkyl preferably methyl, ethyl or n-propyl, benzyl, Ci-C ₅ -acyl preferably C(0)CH ₃ , C(0)C ₂ H ₅ , C(0)n- propyl or C(0)iso-propyl, Ci-C ₅ -alkylester preferably OC(0)CH ₃ , OC(0)C ₂ H ₅ , OC(0)n-propyl or OC(0)iso-propyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH. Most preferred, the substituent R ² is hydrogen. Further preferred, the substituent R ² is selected from the group comprising Ci-C ₅ -alkyl preferably methyl, ethyl or n-propyl, benzyl, Ci-C ₅ -acyl preferably C(0)CH ₃ , C(0)C ₂ H ₅ , C(0)n-propyl or C(0)iso-propyl, Ci-C ₅ -alkylester preferably OC(0)CH ₃ , OC(0)C ₂ H ₅ , OC(0)n-propyl or OC(0)iso- propyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH. Preferred are small alkyl, acyl and ester groups selected from methyl, ethyl, C(0)CH ₃ , C(0)C ₂ H ₅ , OC(0)CH ₃ , OC(0)C ₂ H ₅ , and benzyl. It is also preferred that the substituent R ² is selected from C(0)NH ₂ , NH ₂ or S(0) ₂ OH. These substituents can show a good activity and activation of the glmS riboswitch. Preferably, the substituent R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ and/or aryloxy phosphoramidates according to formula (II) wherein R ⁶ is methyl, ethyl, isopropyl, cyclohexyl or benzyl, X is methoxy and R ⁷ is methyl or another side chain of an amino acid. Preferably, the substituent R ⁵ is hydrogen. Most preferred, the substituent R ⁵ is P(0)(OH) ₂ . Advantageously, in vitro screenings monitoring the ribozyme-catalyzed cleavage reaction showed that compounds wherein the substituent R ⁵ is hydrogen or P(0)(OH) ₂ are capable of efficiently activating the glmS riboswitch.

Further preferred, the substituent R ⁵ is an aryloxy phosphoramidate according to formula (II).

Preferred are aryloxy phosphoramidates wherein R ⁶ is methyl, ethyl, isopropyl, cyclohexyl or benzyl, X is methoxy and R ⁷ is methyl or another side chain of an amino acid. The therapeutic potential of antibacterial compounds can be effectively improved by prodrug technologies aimed at delivering the monophosphates into cells. Via prodrug technologies a prodrug is delivered into the cell, where it may then be further converted to the active species. By an aryloxy phosphoramidate the charges of the phosphate group are fully masked which can provide an efficient passive cell-membrane penetration. Upon entering the cell, the masking groups are enzymatically cleaved to release the phosphorylated molecule.

Aryloxy phosphoramidates according to formula (II) wherein R ⁶ is selected from the group comprising linear or branched Ci-C ₆ -alkyl, benzyl and/or cyclohexyl, and R ⁷ is a side chain of an amino acid, and X is selected from the group comprising CI, Br, I, Ci-C ₆ -alkyl and/or Ci-C ₆ -alkoxy are designed to deliver a monophosphate inside cells. Inside the cell, the monophosphate can be restored. Without being bound to a special theory, it is assumed that after enzymatic, for example by an esterase- mediated, cleavage of R ⁶ an intermediate metabolite can be spontaneously converted into an amino acyl metabolite by liberating the phenyl ring through intramolecular nucleophilic reaction leaving only the remaining amino acid to be released from the phosphate group.

The substituent R ⁷ is a side chain of an amino acid. Preferably, the substituent R ⁷ is a side chain of a naturally occurring amino acid selected from the group comprising glycine, alanine, serine, threonine, arginine, lysine, aspartic acid, glutamic acid, asparagine, glutamine, phenylalanine, tyrosine, tryptophan, leucine, valine, isoleucine, cysteine, methionine, histidine and/or proline, preferably alanine, phenylalanine, proline, valine, leucine, isoleucine, glycine, methionine, and α,α- dimethylglycine. In preferred embodiments the substituent R ⁷ is a linear or branched alkyl group of the type -C _n H _2n -U-D wherein n is 1, 2, 3 or 4, U is selected from the group comprising O, CO, COO, CONH, S, guanidine and/or NH, and D is selected from the group comprising H and/or methyl; -CH ₂ -C ₆ H ₄ -OH; -CH ₂ - imidazole and/or -CH ₂ -indole. Preferably, the substituent R ⁷ is a side chain of an amino acid selected from the group comprising linear or branched Ci-C ₄ -alkyl.

In a preferred embodiment, the substituent R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ and/or aryloxy phosphoramidates according to formula (II) wherein R ⁶ is methyl, ethyl, isopropyl, cyclohexyl or benzyl, X is methoxy and R ⁷ is methyl. In especially preferred embodiments, the compound is selected from the group comprising the formulas (1) and/or (2) as indicated below and/or racemates, enantiomers, diastereomers, solvates, hydrates, and harmaceutically acceptable salts and/or esters thereof:

Ac is acetyl.

Advantageously, in vitro screenings monitoring the ribozyme-catalyzed cleavage reaction showed that particularly the compounds according to formula (1) was capable of efficiently activating the glmS riboswitch. Particularly, the compound according to formula (1) was able to activate the riboswitch in comparable levels to the natural metabolite glucosamine-6-phosphate (GlcN6P). Advantageously, the compounds represent promising candidates for the development of antibacterial compounds. The compounds described herein contain one or more asymmetric centres and may thus give rise to stereo isomers (configurational isomers). The present invention includes all such possible stereo isomers as well as their mixtures, and pharmaceutically acceptable salts thereof. Unless specifically stated otherwise, compounds, groups or substituents denoted with Arabic numerals and such compounds, groups or substituents denoted with Roman numerals differ from each other, that is, compounds, groups or substituents are different compounds, groups or substituents.

Further preferred, the compound according to general formula (I) can be part of a dimer, trimer or oligomer, formed from one compound according to the invention and at least one other compound joined together via a linker linked to element A. Preferably the linker is selected from the group comprising nucleotide linkers, polyethylene glycols, peptide linkers and/or linear or branched, saturated or unsaturated Ci-C ₅₀ -alkyl. Preferably, a nucleotide linker has a length in the range of≥ 1 nucleotide to < 30 nucleotides, preferred in the range of≥ 2 nucleotides to < 15 nucleotides, further preferred in the range of≥ 5 nucleotides to < 15 nucleotides, more preferred in the range of≥ 10 nucleotides to < 15 nucleotides, wherein the nucleotides are selected from the group comprising guanosine, cytidine, adenosine and/or thymidine. A preferred nucleotide is adenosine. Especially preferred linkers are Poly A-linkers. Preferably, a polyethylene glycol linker comprises 1 to 15 polyethylene glycol units, preferred in the range of 1 to 10 polyethylene glycol units, more preferred in the range of 2 to 8 polyethylene glycol units. Preferred are linear polyethylene glycol (PEG) units HO-(CH ₂ CH ₂ 0) _n -H, wherein n is an integer in the range of 1 to 15, preferred in the range of 1 to 10, more preferred in the range of 2 to 8. In preferred embodiments the linker is a peptide linker, wherein the peptide linker preferably comprises amino acids selected from the group comprising glycine, alanine and/or β-alanine. Preferably, the peptide linker comprises in the range of 2 to 4 amino acids. Preferably, the peptide linker comprises β-β- alanine units. Preferably, the peptide linker comprises in the range of 2 to 4 β-alanine units. In preferred embodiments the linker is a linear or branched, saturated or unsaturated Ci-C ₄₀ -alkyl group, preferred a Ci-C ₃₀ alkyl group, more preferred a C ₂ -C ₂ o - alkyl group Preferably, the linker is an alkyl group -(CH ₂ ) _n - wherein n is an integer in the range of 1 to 40, preferred in the range of 1 to 30, further preferred in the range of 2 to 20, more preferred in the range of 2 to 18, even more preferred n is 2, 6,

12 or 18.

A further aspect of the present invention relates to a compound according to general formula (I) as given as follows and/or racemates, enantiomers, diastereomers, solvates, hydrates, and

pharmaceutically acceptable salts and/or esters thereof:

wherein:

R ¹ is selected from the group comprising H, OH, SH and/or NH ₂ ;

R ² is selected from the group comprising hydrogen, Ci-Cio-alkyl, C ₇ -Ci ₄ -arylalkyl wherein the aryl group has 6 to 10 carbon atoms and the alkyl group has 1 to 4 carbon atoms, C(0)Ci-Cio-alkyl, OC(O)C ₁ -C ₁₀ -alkyl, C(O)OC ₁ -C ₁₀ -alkyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH;

R ³ is selected from the group comprising OH, SH and/or NH ₂ ;

R ⁴ is selected from the group comprising OH, SH and/or NH ₂ ;

R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ , S(0) ₂ OH, P(S)(OH) ₂ ,

P(0)OHSH, S(0) ₂ SH and/or aryloxy phosphoramidates according to general formula (II)

⁶

(II)

wherein:

R ⁶ is selected from the group comprising linear or branched Ci-C ₆ -alkyl, benzyl and/or cyclohexyl; R ⁷ is a side chain of an amino acid selected from the group comprising hydrogen; linear or branched Ci-C ₄ -alkyl; linear or branched alkyl groups of the type -C _n H _2n -U-D wherein n is 1, 2, 3 or 4, U is selected from the group comprising O, CO, COO, CONH, S, guanidine and/or NH and D is selected from the group comprising H and/or Ci-C ₃ -alkyl; -CH ₂ -C ₆ H ₄ -Y wherein Y is selected from the group comprising OH, SH, Ci-C ₃ -alkyl and/or NH ₂ ; -CH ₂ -imidazole; -CH ₂ -indole; -CH ₂ -(furanyl-3-yl); -CH ₂ - (pyridyl-3-yl) and/or -CH ₂ -(imidazolyl-3-yl);

X is selected from the group comprising CI, Br, I, Ci-C ₆ -alkyl and/or Ci-C ₆ -alkoxy;

8 8 9 8 9

A is selected from the group comprising S, NR , C=CR°R ^* and/or CR°R', wherein

R ⁸ , R ⁹ is selected, the same or each independently of the other, from the group comprising hydrogen, Ci-Cio-alkyl, C ₂ -Ci ₀ -alkenyl, C ₆ -Ci ₀ -aryl, C ₇ -Ci ₄ -arylalkyl wherein the aryl group has 6 to 10 carbon atoms and the alkyl group has 1 to 4 carbon atoms, C(0)Ci-Cio-alkyl, C(O)OCi-Ci ₀ -alkyl, C(0)NH ₂ , NH ₂ , S(0) ₂ OH and/or a linker,

for use as a medicament.

Preferably, the substituent A is selected from the group comprising S, NR ⁸ and/or CR ⁸ R ⁹ , wherein R ⁸ and R ⁹ are selected, the same or each independently of the other, from the group comprising hydrogen, Ci-C ₅ -alkyl, C ₆ -Ci ₀ -aryl, or C ₂ -C ₅ -alkenyl. In a preferred embodiment, the element A is a group -CH ₂ - and the compound has the formula (III) as indicated below and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof:

Preferably, the substituent R ¹ is a hydroxyl group. Further, the substituent R ¹ can be hydrogen. Further preferred, the substituent R ³ is a hydroxyl group. Further preferred, the substituent R ⁴ is a hydroxyl group. In a preferred embodiment of the compound according to the invention the substituents R ¹ , R ³ and R ⁴ are OH. In another preferred embodiment of the compound according to the invention the substituent R ¹ is hydrogen and the substituents R ³ and R ⁴ are OH.

In a preferred embodiment, the substituent R ² is selected from the group comprising hydrogen, C ₁ -C5- alkyl preferably methyl, ethyl or n-propyl, benzyl, Ci-C ₅ -acyl preferably C(0)CH ₃ , C(0)C ₂ H ₅ , C(0)n- propyl or C(0)iso-propyl, Ci-C ₅ -alkylester preferably OC(0)CH ₃ , OC(0)C ₂ H ₅ , OC(0)n-propyl or OC(0)iso-propyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH. Most preferred, the substituent R ² is hydrogen. Further preferred, the substituent R ² is selected from the group comprising Ci-C ₅ -alkyl preferably methyl, ethyl or n-propyl, benzyl, Ci-C ₅ -acyl preferably C(0)CH ₃ , C(0)C ₂ H ₅ , C(0)n-propyl or C(0)iso-propyl, Ci-C ₅ -alkylester preferably OC(0)CH ₃ , OC(0)C ₂ H ₅ , OC(0)n-propyl or OC(0)iso- propyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH. Preferred are small alkyl, acyl and ester groups selected from methyl, ethyl, C(0)CH ₃ , C(0)C ₂ H ₅ , OC(0)CH ₃ , OC(0)C ₂ H ₅ , and benzyl. It is also preferred that the substituent R ² is selected from C(0)NH ₂ , NH ₂ or S(0) ₂ OH. Preferably, the substituent R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ and/or aryloxy phosphoramidates according to formula (II) wherein R ⁶ is selected from the group comprising methyl, ethyl, isopropyl, cyclohexyl and benzyl, X is methoxy and R ⁷ is methyl or another side chain of an amino acid. Preferably, the substituent R ⁵ is hydrogen. Most preferred, the substituent R ⁵ is P(0)(OH) ₂ . Further preferred, the substituent R ⁵ is an aryloxy phosphoramidate according to formula (II). Preferred are aryloxy phosphoramidates wherein R ⁶ is methyl, ethyl, isopropyl, cyclohexyl or benzyl, X is methoxy and R ⁷ is methyl or another side chain of an amino acid.

The substituent R ⁷ is a side chain of an amino acid. Preferably, the substituent R ⁷ is a side chain of a naturally occurring amino acid selected from the group comprising glycine, alanine, serine, threonine, arginine, lysine, aspartic acid, glutamic acid, asparagine, glutamine, phenylalanine, tyrosine, tryptophan, leucine, valine, isoleucine, cysteine, methionine, histidine and/or proline, preferably alanine, phenylalanine, proline, valine, leucine, isoleucine, glycine, methionine, or α,α- dimethylglycine. In preferred embodiments, the substituent R ⁷ is a linear or branched alkyl groups of the type -C _n H _2n -U-D wherein n is 1, 2, 3 or 4, U is selected from the group comprising O, CO, COO, CONH, S, guanidine and/or NH, and D is selected from the group comprising H and/or methyl; -CH ₂ - C ₅ H ₄ -OH; -CH ₂ -imidazole and/or -CH ₂ -indole. Preferably, the substituent R ⁷ is a side chain of an amino acid selected from the group comprising hydrogen; linear or branched Ci-C ₄ -alkyl, most preferred methyl.

In a preferred embodiment, the substituent R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ and/or aryloxy phosphoramidates according to formula (II) wherein R ⁶ is methyl, ethyl, isopropyl, cyclohexyl or benzyl, X is methoxy and R ⁷ is methyl.

In especially preferred embodiments, the compound is selected from the group comprising the formulas (1), (2), (3) and/or (4) as indicated below and/or racemates, enantiomers, diastereomers, solvates, h drates, and pharmaceutically acceptable salts and/or esters thereof:

Ac is acetyl.

In an especially preferred embodiment, the compound is selected from the group comprising the formulas (1) and/or (2) as indicated above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof.

Further preferred, the compound according to general formula (I) can be part of a dimer, trimer or oligomer, formed from one compound according to the invention and at least one other compound joined together via a linker linked to element A. Preferably the linker is selected from the group comprising nucleotide linkers, polyethylene glycols, peptide linkers and/or linear or branched, saturated or unsaturated Ci-C ₅₀ -alkyl.

Preferably, a nucleotide linker has a length in the range of≥ 1 nucleotide to < 30 nucleotides, preferred in the range of≥ 2 nucleotides to < 15 nucleotides, further preferred in the range of≥ 5 nucleotides to < 15 nucleotides, more preferred in the range of≥ 10 nucleotides to < 15 nucleotides, wherein the nucleotides are selected from the group comprising guanosine, cytidine, adenosine and/or thymidine. A preferred nucleotide is adenosine. Especially preferred linkers are Poly A-linkers. Preferably, a polyethylene glycol linker comprises 1 to 15 polyethylene glycol units, preferred in the range of 1 to 10 polyethylene glycol units, more preferred in the range of 2 to 8 polyethylene glycol units. Preferred are linear polyethylene glycol (PEG) units HO-(CH ₂ CH ₂ 0) _n -H, wherein n is an integer in the range of 1 to 15, preferred in the range of 1 to 10, more preferred in the range of 2 to 8. In preferred embodiments the linker is a peptide linker, wherein the peptide linker preferably comprises amino acids selected from the group comprising glycine, alanine and/or β-alanine. Preferably, the peptide linker comprises in the range of 2 to 4 amino acids. Preferably, the peptide linker comprises β-β- alanine units. Preferably, the peptide linker comprises in the range of 2 to 4 β-alanine units. In preferred embodiments the linker is a linear or branched, saturated or unsaturated Ci-C ₄₀ -alkyl group, preferred a Ci-C ₃₀ alkyl group, more preferred a C ₂ -C ₂ o - alkyl group Preferably, the linker is an alkyl group -(CH ₂ ) _n - wherein n is an integer in the range of 1 to 40, preferred in the range of 1 to 30, further preferred in the range of 2 to 20, more preferred in the range of 2 to 18, even more preferred n is 2, 6, 12 or 18.

A further aspect of the present invention relates to a compound according to general formula (I) as given as follows and/or racemates, enantiomers, diastereomers, solvates, hydrates, and

pharmaceutically acceptable salts and/or esters thereof:

wherein:

R ¹ is selected from the group comprising H, OH, SH and/or NH ₂ ;

R ² is selected from the group comprising hydrogen, Ci-Cio-alkyl, C ₇ -Ci ₄ -arylalkyl wherein the aryl group has 6 to 10 carbon atoms and the alkyl group has 1 to 4 carbon atoms, C(0)Ci-Cio-alkyl, OC(O)C ₁ -C ₁₀ -alkyl, C(O)OC ₁ -C ₁₀ -alkyl, C(0)NH ₂ , NH ₂ and/or

S(0) ₂ OH;

R ³ is selected from the group comprising OH, SH and/or NH ₂ ;

R ⁴ is selected from the group comprising OH, SH and/or NH ₂ ;

R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ , S(0) ₂ OH, P(S)(OH) ₂ ,

P(0)OHSH, S(0) ₂ SH and/or aryloxy phosphoramidates according to general formula (II)

wherein:

R ⁶ is selected from the group comprising linear or branched Ci-C ₆ -alkyl, benzyl and/or cyclohexyl;

R ⁷ is a side chain of an amino acid selected from the group comprising hydrogen; linear or branched Ci-C ₄ -alkyl; linear or branched alkyl groups of the type -C _n H _2n -U-D wherein n is 1, 2, 3 or 4, U is selected from the group comprising O, CO, COO, CONH, S, guanidine and/or NH and D is selected from the group comprising H and/or Ci-C ₃ -alkyl; -CH ₂ -C ₆ H ₄ -Y wherein Y is selected from the group comprising OH, SH, Ci-C ₃ -alkyl and/or NH ₂ ; -CH ₂ -imidazole; -CH ₂ -indole; -CH ₂ -(furanyl-3-yl); -CH ₂ - (pyridyl-3-yl) and/or -CH ₂ -(imidazolyl-3-yl);

X is selected from the group comprising CI, Br, I, Ci-C ₆ -alkyl and/or Ci-C ₆ -alkoxy;

8 8 9 8 9

is selected from the group comprising S, NR , C=CR°R ^* and/or CR°R', wherein R ⁸ , R ⁹ is selected, the same or each independently of the other, from the group comprising hydrogen, Ci-Cio-alkyl, C ₂ -Ci ₀ -alkenyl, C ₆ -Ci ₀ -aryl, C ₇ -Ci ₄ -arylalkyl wherein the aryl group has 6 to 10 carbon atoms and the alkyl group has 1 to 4 carbon atoms, C(0)Ci-Cio-alkyl, C(O)OCi-Ci ₀ -alkyl, C(0)NH ₂ , NH ₂ , S(0) ₂ OH and/or a linker,

for use in the therapeutic and/or prophylactic treatment of a bacterial infection, particularly for use as an antibiotic.

The term "prophylactic treatment" according to the invention is to be understood as meaning that the compositions according to the invention can be applied before symptoms of the bacterial infection are manifest. Especially, the term "prophylactic treatment" is to be understood as meaning a medical treatment. It can be preferred to use the compounds according to the invention in a prophylactic treatment.

Surprisingly it was found that the compounds according to the general formula (I) can be effective against bacterial growth. Especially, the compounds according to formulas (1) and (3) were found to effectively inhibit the growth of Staphylococcus aureus.

One particular advantage of the compounds according to the invention is that the compounds are especially usable as an antibiotic, particularly against the multiresistant Staphylococcus aureus strain.

Preferably, the substituent A is selected from the group comprising S, NR ⁸ and/or CR ⁸ R ⁹ , wherein R ⁸ and R ⁹ are selected, the same or each independently of the other, from the group comprising hydrogen, Ci-C ₅ -alkyl, C ₆ -Ci ₀ -aryl, or C ₂ -C ₅ -alkenyl. In a preferred embodiment, the element A is a group -CH ₂ - and the compound has the formula (III) as indicated below and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof:

Preferably, the substituent R ¹ is a hydroxyl group. Further, the substituent R ¹ can be hydrogen. Further preferred, the substituent R ³ is a hydroxyl group. Further preferred, the substituent R ⁴ is a hydroxyl group. In a preferred embodiment of the compound according to the invention the substituents R ¹ , R ³ and R ⁴ are OH. In another preferred embodiment of the compound according to the invention the substituent R ¹ is hydrogen and the substituents R ³ and R ⁴ are OH.

In a preferred embodiment, the substituent R ² is selected from the group comprising hydrogen, Ci-C ₅ - alkyl preferably methyl, ethyl or n-propyl, benzyl, Ci-C ₅ -acyl preferably C(0)CH ₃ , C(0)C ₂ H ₅ , C(0)n- propyl or C(0)iso-propyl, Ci-C ₅ -alkylester preferably OC(0)CH ₃ , OC(0)C ₂ H ₅ , OC(0)n-propyl or OC(0)iso-propyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH. Most preferred, the substituent R ² is hydrogen. Further preferred, the substituent R ² is selected from the group comprising Ci-C ₅ -alkyl preferably methyl, ethyl or n-propyl, benzyl, Ci-C ₅ -acyl preferably C(0)CH ₃ , C(0)C ₂ H ₅ , C(0)n-propyl or C(0)iso-propyl, Ci-C ₅ -alkylester preferably OC(0)CH ₃ , OC(0)C ₂ H ₅ , OC(0)n-propyl or OC(0)iso- propyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH. Preferred are small alkyl, acyl and ester groups selected from methyl, ethyl, C(0)CH ₃ , C(0)C ₂ H ₅ , OC(0)CH ₃ , OC(0)C ₂ H ₅ , and benzyl. It is also preferred that the substituent R ² is selected from C(0)NH ₂ , NH ₂ or S(0) ₂ OH.

Preferably, the substituent R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ and/or aryloxy phosphoramidates according to formula (II) wherein R ⁶ is selected from the group comprising methyl, ethyl, isopropyl, cyclohexyl and benzyl, X is methoxy and R ⁷ is methyl or another side chain of an amino acid. Preferably, the substituent R ⁵ is hydrogen. Most preferred, the substituent R ⁵ is

P(0)(OH) ₂ . Further preferred, the substituent R ⁵ is an aryloxy phosphoramidate according to formula (II). Preferred are aryloxy phosphoramidates wherein R ⁶ is methyl, ethyl, isopropyl, cyclohexyl or benzyl, X is methoxy and R ⁷ is methyl or another side chain of an amino acid. The substituent R ⁷ is a side chain of an amino acid. Preferably, the substituent R ⁷ is a side chain of a naturally occurring amino acid selected from the group comprising glycine, alanine, serine, threonine, arginine, lysine, aspartic acid, glutamic acid, asparagine, glutamine, phenylalanine, tyrosine, tryptophan, leucine, valine, isoleucine, cysteine, methionine, histidine and/or proline, preferably alanine, phenylalanine, proline, valine, leucine, isoleucine, glycine, methionine, or α,α- dimethylglycine. In preferred embodiments, the substituent R ⁷ is a linear or branched alkyl groups of the type -C _n H _2n -U-D wherein n is 1, 2, 3 or 4, U is selected from the group comprising O, CO, COO, CONH, S, guanidine and/or NH, and D is selected from the group comprising H and/or methyl; -CH ₂ - C ₆ H ₄ -OH; -CH ₂ -imidazole and/or -CH ₂ -indole. Preferably, the substituent R ⁷ is a side chain of an amino acid selected from the group comprising hydrogen; linear or branched Ci-C ₄ -alkyl, most preferred methyl.

In a preferred embodiment, the substituent R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ and/or aryloxy phosphoramidates according to formula (II) wherein R ⁶ is methyl, ethyl, isopropyl, cyclohexyl or benzyl, X is methoxy and R ⁷ is methyl.

In a preferred embodiment, the compound according to general formula (I) for use in the therapeutic and/or prophylactic treatment of a bacterial infection, particularly for use as an antibiotic, comprises an element A being a group -CH ₂ -, the substituents R ¹ , R ³ , and R ⁴ being OH, R ² is hydrogen or C(0)CH ₃ , and R ⁵ is hydrogen or P(0)(OH) ₂ .

In especially preferred embodiments, the compound is selected from the group comprising the formulas (1), (2), (3) and/or (4) as indicated above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof. The compounds according to the general formulas (1), (2), (3) and (4) can be effective in the treatment of a bacterial infection, particularly as an antibiotic. Especially, the compounds according to formulas (1) and (3) were found to effectively inhibit bacterial growth of Staphylococcus aureus.

Further preferred, the compound according to general formula (I) can be part of a dimer, trimer or oligomer, formed from one compound according to the invention and at least one other compound joined together via a linker linked to element A. Preferably the linker is selected from the group comprising nucleotide linkers, polyethylene glycols, peptide linkers and/or linear or branched, saturated or unsaturated Ci-C ₅₀ -alkyl.

Preferably, a nucleotide linker has a length in the range of≥ 1 nucleotide to < 30 nucleotides, preferred in the range of≥ 2 nucleotides to < 15 nucleotides, further preferred in the range of≥ 5 nucleotides to < 15 nucleotides, more preferred in the range of≥ 10 nucleotides to < 15 nucleotides, wherein the nucleotides are selected from the group comprising guanosine, cytidine, adenosine and/or thymidine. A preferred nucleotide is adenosine. Especially preferred linkers are Poly A-linkers. Preferably, a polyethylene glycol linker comprises 1 to 15 polyethylene glycol units, preferred in the range of 1 to 10 polyethylene glycol units, more preferred in the range of 2 to 8 polyethylene glycol units. Preferred are linear polyethylene glycol (PEG) units HO-(CH ₂ CH ₂ 0) _n -H, wherein n is an integer in the range of 1 to 15, preferred in the range of 1 to 10, more preferred in the range of 2 to 8. In preferred embodiments the linker is a peptide linker, wherein the peptide linker preferably comprises amino acids selected from the group comprising glycine, alanine and/or β-alanine. Preferably, the peptide linker comprises in the range of 2 to 4 amino acids. Preferably, the peptide linker comprises β-β- alanine units. Preferably, the peptide linker comprises in the range of 2 to 4 β-alanine units. In preferred embodiments the linker is a linear or branched, saturated or unsaturated Ci-C ₄₀ -alkyl group, preferred a Ci-C ₃₀ alkyl group, more preferred a C ₂ -C ₂ o - alkyl group Preferably, the linker is an alkyl group -(CH ₂ ) _n - wherein n is an integer in the range of 1 to 40, preferred in the range of 1 to 30, further preferred in the range of 2 to 20, more preferred in the range of 2 to 18, even more preferred n is 2, 6,

12 or 18.

A further aspect of the present invention relates to a pharmaceutical composition comprising as an active ingredient a compound according to general formula (I) as given as follows and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof:

wherein:

R is selected from the group comprising H, OH, SH and/or NH ₂ ;

Pv ² is selected from the group comprising hydrogen, Ci-Cio-alkyl, C ₇ -Ci ₄ -arylalkyl wherein the aryl group has 6 to 10 carbon atoms and the alkyl group has 1 to 4 carbon atoms, C(O)C ₁ -C ₁₀ -alkyl, OC(O)C ₁ -C ₁₀ -alkyl, C(O)OC ₁ -C ₁₀ -alkyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH;

R ³ is selected from the group comprising OH, SH and/or NH ₂ ;

R ⁴ is selected from the group comprising OH, SH and/or NH ₂ ;

R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ , S(0) ₂ OH, P(S)(OH) ₂ ,

P(0)OHSH, S(0) ₂ SH and/or aryloxy phosphoramidates according to general formula (II)

wherein:

R ⁶ is selected from the group comprising linear or branched Ci-C ₆ -alkyl, benzyl and/or cyclohexyl;

R ⁷ is a side chain of an amino acid selected from the group comprising hydrogen; linear or branched Ci-C ₄ -alkyl; linear or branched alkyl groups of the type -C _n H _2n -U-D wherein n is 1, 2, 3 or 4, U is selected from the group comprising O, CO, COO, CONH, S, guanidine and/or NH and D is selected from the group comprising H and/or Ci-C ₃ -alkyl; -CH ₂ -C ₆ H ₄ -Y wherein Y is selected from the group comprising OH, SH, Ci-C ₃ -alkyl and/or NH ₂ ; -CH ₂ -imidazole; -CH ₂ -indole; -CH ₂ -(furanyl-3-yl); -CH ₂ - (pyridyl-3-yl) and/or -CH ₂ -(imidazolyl-3-yl);

X is selected from the group comprising CI, Br, I, Ci-C ₆ -alkyl and/or Ci-C ₆ -alkoxy;

8 8 9 8 9

A is selected from the group comprising S, NR , C=CR°R ^* and/or CR°R', wherein

R ⁸ , R ⁹ is selected, the same or each independently of the other, from the group comprising hydrogen, Ci-Cio-alkyl, C ₂ -Ci ₀ -alkenyl, C ₆ -Ci ₀ -aryl, C ₇ -Ci ₄ -arylalkyl wherein the aryl group has 6 to 10 carbon atoms and the alkyl group has 1 to 4 carbon atoms, C(0)Ci-Cio-alkyl, C(O)OCi-Ci ₀ -alkyl, C(0)NH ₂ , NH ₂ , S(0) ₂ OH and/or a linker.

Preferably, the substituent A is selected from the group comprising S, NR ⁸ and/or CR ⁸ R ⁹ , wherein R ⁸ and R ⁹ are selected, the same or each independently of the other, from the group comprising hydrogen, Ci-C ₅ -alkyl, C ₆ -Ci ₀ -aryl, or C ₂ -C ₅ -alkenyl. In a preferred embodiment, the element A is a group -CH ₂ - and the compound has the formula (III) as indicated below and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof:

Preferably, the substituent R ¹ is a hydroxyl group. Further, the substituent R ¹ can be hydrogen. Further preferred, the substituent R ³ is a hydroxyl group. Further preferred, the substituent R ⁴ is a hydroxyl group. In a preferred embodiment of the compound according to the invention the substituents R ¹ , R ³ and R ⁴ are OH. In another preferred embodiment of the compound according to the invention the substituent R ¹ is hydrogen and the substituents R ³ and R ⁴ are OH.

In a preferred embodiment, the substituent R ² is selected from the group comprising hydrogen, Ci-C ₅ - alkyl preferably methyl, ethyl or n-propyl, benzyl, Ci-C ₅ -acyl preferably C(0)CH ₃ , C(0)C ₂ H ₅ , C(0)n- propyl or C(0)iso-propyl, Ci-C ₅ -alkylester preferably OC(0)CH ₃ , OC(0)C ₂ H ₅ , OC(0)n-propyl or OC(0)iso-propyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH. Most preferred, the substituent R ² is hydrogen. Further preferred, the substituent R ² is selected from the group comprising Ci-C ₅ -alkyl preferably methyl, ethyl or n-propyl, benzyl, Ci-C ₅ -acyl preferably C(0)CH ₃ , C(0)C ₂ H ₅ , C(0)n-propyl or C(0)iso-propyl, Ci-C ₅ -alkylester preferably OC(0)CH ₃ , OC(0)C ₂ H ₅ , OC(0)n-propyl or OC(0)iso- propyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH. Preferred are small alkyl, acyl and ester groups selected from methyl, ethyl, C(0)CH ₃ , C(0)C ₂ H ₅ , OC(0)CH ₃ , OC(0)C ₂ H ₅ , and benzyl. It is also preferred that the substituent R ² is selected from C(0)NH ₂ , NH ₂ or S(0) ₂ OH.

Preferably, the substituent R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ and/or aryloxy phosphoramidates according to formula (II) wherein R ⁶ is selected from the group comprising methyl, ethyl, isopropyl, cyclohexyl and benzyl, X is methoxy and R ⁷ is methyl or another side chain of an amino acid. Preferably, the substituent R ⁵ is hydrogen. Most preferred, the substituent R ⁵ is P(0)(OH) ₂ . Further preferred, the substituent R ⁵ is an aryloxy phosphoramidate according to formula (II). Preferred are aryloxy phosphoramidates wherein R ⁶ is methyl, ethyl, isopropyl, cyclohexyl or benzyl, X is methoxy and R ⁷ is methyl or another side chain of an amino acid. The substituent R ⁷ is a side chain of an amino acid. Preferably, the substituent R ⁷ is a side chain of a naturally occurring amino acid selected from the group comprising glycine, alanine, serine, threonine, arginine, lysine, aspartic acid, glutamic acid, asparagine, glutamine, phenylalanine, tyrosine, tryptophan, leucine, valine, isoleucine, cysteine, methionine, histidine and/or proline, preferably alanine, phenylalanine, proline, valine, leucine, isoleucine, glycine, methionine, or α,α- dimethylglycine. In preferred embodiments, the substituent R ⁷ is a linear or branched alkyl groups of the type -C _n H _2n -U-D wherein n is 1, 2, 3 or 4, U is selected from the group comprising O, CO, COO, CONH, S, guanidine and/or NH, and D is selected from the group comprising H and/or methyl; -CH ₂ - C ₆ H ₄ -OH; -CH ₂ -imidazole and/or -CH ₂ -indole. Preferably, the substituent R ⁷ is a side chain of an amino acid selected from the group comprising hydrogen; linear or branched Ci-C ₄ -alkyl, most preferred methyl.

In a preferred embodiment, the substituent R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ and/or aryloxy phosphoramidates according to formula (II) wherein R ⁶ is methyl, ethyl, isopropyl, cyclohexyl or benzyl, X is methoxy and R ⁷ is methyl.

In especially preferred embodiments, the compound is selected from the group comprising the formulas (1), (2), (3) and/or (4) as indicated above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof. In an especially preferred embodiment, the pharmaceutical composition comprises a compound selected from the group comprising the formulas (1) and/or (2) as indicated above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof. In a further especially preferred embodiment, the pharmaceutical composition comprises a compound selected from the group comprising the formulas (1) and/or (2) as indicated above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof.

Further preferred, the compound according to general formula (I) can be part of a dimer, trimer or oligomer, formed from one compound according to the invention and at least one other compound joined together via a linker linked to element A. Preferably the linker is selected from the group comprising nucleotide linkers, polyethylene glycols, peptide linkers and/or linear or branched, saturated or unsaturated Ci-C ₅₀ -alkyl. Preferably, a nucleotide linker has a length in the range of≥ 1 nucleotide to < 30 nucleotides, preferred in the range of≥ 2 nucleotides to < 15 nucleotides, further preferred in the range of≥ 5 nucleotides to < 15 nucleotides, more preferred in the range of≥ 10 nucleotides to < 15 nucleotides, wherein the nucleotides are selected from the group comprising guanosine, cytidine, adenosine and/or thymidine. A preferred nucleotide is adenosine. Especially preferred linkers are Poly A-linkers. Preferably, a polyethylene glycol linker comprises 1 to 15 polyethylene glycol units, preferred in the range of 1 to 10 polyethylene glycol units, more preferred in the range of 2 to 8 polyethylene glycol units. Preferred are linear polyethylene glycol (PEG) units HO-(CH ₂ CH ₂ 0) _n -H, wherein n is an integer in the range of 1 to 15, preferred in the range of 1 to 10, more preferred in the range of 2 to 8. In preferred embodiments the linker is a peptide linker, wherein the peptide linker preferably comprises amino acids selected from the group comprising glycine, alanine and/or β-alanine. Preferably, the peptide linker comprises in the range of 2 to 4 amino acids. Preferably, the peptide linker comprises β-β- alanine units. Preferably, the peptide linker comprises in the range of 2 to 4 β-alanine units. In preferred embodiments the linker is a linear or branched, saturated or unsaturated Ci-C ₄₀ -alkyl group, preferred a Ci-C ₃₀ alkyl group, more preferred a C ₂ -C ₂ o - alkyl group Preferably, the linker is an alkyl group -(CH ₂ ) _n - wherein n is an integer in the range of 1 to 40, preferred in the range of 1 to 30, further preferred in the range of 2 to 20, more preferred in the range of 2 to 18, even more preferred n is 2, 6, 12 or 18.

A further aspect of the present invention relates to a pharmaceutical composition comprising as an active ingredient a compound according to general formula (I) as given as above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof for use in the therapeutic and/or prophylactic treatment of a bacterial infection, particularly for use as an antibiotic. Preferably, the pharmaceutical composition for use in the therapeutic and/or prophylactic treatment of a bacterial infection, particularly for use as an antibiotic comprises a compound selected from the group comprising the formulas (1), (2), (3) and/or (4) as indicated above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof. The pharmaceutical composition preferably is useful as an antibiotic.

The present invention also relates to an antibiotic comprising, as an active ingredient, a compound according to general formula (I) as given as follows and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof:

wherein:

R ¹ is selected from the group comprising H, OH, SH and/or NH ₂ ;

R ² is selected from the group comprising hydrogen, Ci-Cio-alkyl, C ₇ -Ci ₄ -arylalkyl wherein the aryl group has 6 to 10 carbon atoms and the alkyl group has 1 to 4 carbon atoms, C(0)Ci-Cio-alkyl, OC(O)C ₁ -C ₁₀ -alkyl, C(O)OC ₁ -C ₁₀ -alkyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH;

R ³ is selected from the group comprising OH, SH and/or NH ₂ ;

R ⁴ is selected from the group comprising OH, SH and/or NH ₂ ;

R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ , S(0) ₂ OH, P(S)(OH) ₂ ,

P(0)OHSH, S(0) ₂ SH and/or aryloxy phosphoramidates according to general formula (II)

wherein:

R ⁶ is selected from the group comprising linear or branched Ci-C ₆ -alkyl, benzyl and/or cyclohexyl;

R ⁷ is a side chain of an amino acid selected from the group comprising hydrogen; linear or branched Ci-C ₄ -alkyl; linear or branched alkyl groups of the type -C _n H _2n -U-D wherein n is 1, 2, 3 or 4, U is selected from the group comprising O, CO, COO, CONH, S, guanidine and/or NH and D is selected from the group comprising H and/or Ci-C ₃ -alkyl; -CH ₂ -C ₆ H ₄ -Y wherein Y is selected from the group comprising OH, SH, Ci-C ₃ -alkyl and/or NH ₂ ; -CH ₂ -imidazole; -CH ₂ -indole; -CH ₂ -(furanyl-3-yl); -CH ₂ - (pyridyl-3-yl) and/or -CH ₂ -(imidazolyl-3-yl);

X is selected from the group comprising CI, Br, I, Ci-C ₆ -alkyl and/or Ci-C ₆ -alkoxy;

8 8 9 8 9

A is selected from the group comprising S, NR , C=CR°R ^* and/or CR°R', wherein

R ⁸ , R ⁹ is selected, the same or each independently of the other, from the group comprising hydrogen, Ci-Cio-alkyl, C ₂ -Ci ₀ -alkenyl, C ₆ -Ci ₀ -aryl, C ₇ -Ci ₄ -arylalkyl wherein the aryl group has 6 to 10 carbon atoms and the alkyl group has 1 to 4 carbon atoms, C(0)Ci-Cio-alkyl, C(O)OCi-Ci ₀ -alkyl, C(0)NH ₂ , NH ₂ , S(0) ₂ OH and/or a linker.

Preferably, the substituent A is selected from the group comprising S, NR ⁸ and/or CR ⁸ R ⁹ , wherein R ⁸ and R ⁹ are selected, the same or each independently of the other, from the group comprising hydrogen, Ci-C ₅ -alkyl, C ₆ -Ci ₀ -aryl, or C ₂ -C ₅ -alkenyl. In a preferred embodiment, the element A is a group -CH ₂ - and the compound has the formula (III) as indicated below and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof:

Preferably, the substituent R ¹ is a hydroxyl group. Further, the substituent R ¹ can be hydrogen. Further preferred, the substituent R ³ is a hydroxyl group. Further preferred, the substituent R ⁴ is a hydroxyl group. In a preferred embodiment of the compound according to the invention the substituents R ¹ , R ³ and R ⁴ are OH. In another preferred embodiment of the compound according to the invention the substituent R ¹ is hydrogen and the substituents R ³ and R ⁴ are OH.

In a preferred embodiment, the substituent R ² is selected from the group comprising hydrogen, Ci-C ₅ - alkyl preferably methyl, ethyl or n-propyl, benzyl, Ci-C ₅ -acyl preferably C(0)CH ₃ , C(0)C ₂ H ₅ , C(0)n- propyl or C(0)iso-propyl, Ci-C ₅ -alkylester preferably OC(0)CH ₃ , OC(0)C ₂ H ₅ , OC(0)n-propyl or OC(0)iso-propyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH. Most preferred, the substituent R ² is hydrogen. Further preferred, the substituent R ² is selected from the group comprising Ci-C ₅ -alkyl preferably methyl, ethyl or n-propyl, benzyl, Ci-C ₅ -acyl preferably C(0)CH ₃ , C(0)C ₂ H ₅ , C(0)n-propyl or C(0)iso-propyl, Ci-C ₅ -alkylester preferably OC(0)CH ₃ , OC(0)C ₂ H ₅ , OC(0)n-propyl or OC(0)iso- propyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH. Preferred are small alkyl, acyl and ester groups selected from methyl, ethyl, C(0)CH ₃ , C(0)C ₂ H ₅ , OC(0)CH ₃ , OC(0)C ₂ H ₅ , and benzyl. It is also preferred that the substituent R ² is selected from C(0)NH ₂ , NH ₂ or S(0) ₂ OH. Preferably, the substituent R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ and/or aryloxy phosphoramidates according to formula (II) wherein R ⁶ is selected from the group comprising methyl, ethyl, isopropyl, cyclohexyl and benzyl, X is methoxy and R ⁷ is methyl or another side chain of an amino acid. Preferably, the substituent R ⁵ is hydrogen. Most preferred, the substituent R ⁵ is P(0)(OH) ₂ . Further preferred, the substituent R ⁵ is an aryloxy phosphoramidate according to formula (II). Preferred are aryloxy phosphoramidates wherein R ⁶ is methyl, ethyl, isopropyl, cyclohexyl or benzyl, X is methoxy and R ⁷ is methyl or another side chain of an amino acid. The substituent R ⁷ is a side chain of an amino acid. Preferably, the substituent R ⁷ is a side chain of a naturally occurring amino acid selected from the group comprising glycine, alanine, serine, threonine, arginine, lysine, aspartic acid, glutamic acid, asparagine, glutamine, phenylalanine, tyrosine, tryptophan, leucine, valine, isoleucine, cysteine, methionine, histidine and/or proline, preferably alanine, phenylalanine, proline, valine, leucine, isoleucine, glycine, methionine, or α,α- dimethylglycine. In preferred embodiments, the substituent R ⁷ is a linear or branched alkyl groups of the type -C _n H _2n -U-D wherein n is 1, 2, 3 or 4, U is selected from the group comprising O, CO, COO, CONH, S, guanidine and/or NH, and D is selected from the group comprising H and/or methyl; -CH ₂ - C ₆ H ₄ -OH; -CH ₂ -imidazole and/or -CH ₂ -indole. Preferably, the substituent R ⁷ is a side chain of an amino acid selected from the group comprising hydrogen; linear or branched Ci-C ₄ -alkyl, most preferred methyl.

In a preferred embodiment, the substituent R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ and/or aryloxy phosphoramidates according to formula (II) wherein R ⁶ is methyl, ethyl, isopropyl, cyclohexyl or benzyl, X is methoxy and R ⁷ is methyl.

In a preferred embodiment, the antibiotic comprises compound according to general formula (I) comprising an element A being a group -CH ₂ -, the substituents R ¹ , R ³ , and R ⁴ being OH, R ² is hydrogen or C(0)CH ₃ , and R ⁵ is hydrogen or P(0)(OH) ₂ .

Preferably, the present invention relates to a pharmaceutical composition comprising as an active ingredient compounds according to the formulas (1), (2), (3) and/or (4) as indicated above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof. In a preferred embodiment, the antibiotic comprises as an active ingredient compounds according to the formulas (1), (2), (3) and/or (4) as indicated above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof. Especially, the compounds according to formulas (1) and (3) were found to effectively inhibit bacterial growth of Staphylococcus aureus. Further preferred, the compound according to general formula (I) can be part of a dimer, trimer or oligomer, formed from one compound according to the invention and at least one other compound joined together via a linker linked to element A. Preferably the linker is selected from the group comprising nucleotide linkers, polyethylene glycols, peptide linkers and/or linear or branched, saturated or unsaturated Ci-C ₅₀ -alkyl.

Preferably, a nucleotide linker has a length in the range of≥ 1 nucleotide to < 30 nucleotides, preferred in the range of≥ 2 nucleotides to < 15 nucleotides, further preferred in the range of≥ 5 nucleotides to < 15 nucleotides, more preferred in the range of≥ 10 nucleotides to < 15 nucleotides, wherein the nucleotides are selected from the group comprising guanosine, cytidine, adenosine and/or thymidine. A preferred nucleotide is adenosine. Especially preferred linkers are Poly A-linkers. Preferably, a polyethylene glycol linker comprises 1 to 15 polyethylene glycol units, preferred in the range of 1 to 10 polyethylene glycol units, more preferred in the range of 2 to 8 polyethylene glycol units. Preferred are linear polyethylene glycol (PEG) units HO-(CH ₂ CH ₂ 0) _n -H, wherein n is an integer in the range of 1 to 15, preferred in the range of 1 to 10, more preferred in the range of 2 to 8. In preferred embodiments the linker is a peptide linker, wherein the peptide linker preferably comprises amino acids selected from the group comprising glycine, alanine and/or β-alanine. Preferably, the peptide linker comprises in the range of 2 to 4 amino acids. Preferably, the peptide linker comprises β-β- alanine units. Preferably, the peptide linker comprises in the range of 2 to 4 β-alanine units. In preferred embodiments the linker is a linear or branched, saturated or unsaturated Ci-C ₄₀ -alkyl group, preferred a Ci-C ₃₀ alkyl group, more preferred a C ₂ -C ₂ o - alkyl group Preferably, the linker is an alkyl group -(CH ₂ ) _n - wherein n is an integer in the range of 1 to 40, preferred in the range of 1 to 30, further preferred in the range of 2 to 20, more preferred in the range of 2 to 18, even more preferred n is 2, 6, 12 or 18.

The compounds and/or racemates, enantiomers, diastereomers, solvates, hydrates, and

pharmaceutically acceptable salts and/or esters thereof can be included in pharmaceutical

compositions in combination with one or more other therapeutically active compounds. The pharmaceutical composition particularly is usable as an antibiotic. Further, the compounds according to the present invention are usable in form of solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof.

Usable are pharmaceutically acceptable salts of the compounds according to the present invention. The term "pharmaceutically acceptable salts" refers to salts prepared from pharmaceutically acceptable non-toxic bases or acids.

When the compound of the present invention is acidic, its corresponding salt can be conveniently prepared from pharmaceutically acceptable non-toxic bases, including inorganic bases and organic bases. Preferred salts derived from inorganic bases include ammonium, calcium, magnesium, potassium and sodium salts. Salts derived from pharmaceutically acceptable organic non-toxic bases include salts of primary, secondary, and tertiary amines, as well as cyclic amines.

When the compound of the present invention is basic, its corresponding salt can be conveniently prepared from pharmaceutically acceptable non-toxic acids, including inorganic and organic acids. Such acids include, for example, acetic, benzene sulfonic, benzoic, camphorsulfonic, citric, ethane sulfonic, fumaric, gluconic, glutamic, hydrobromic, hydrochloric, isethionic, lactic, maleic, malic, mandelic, methanesulfonic, mucic, nitric, pamoic, pantothenic, phosphoric, succinic, sulfuric, tartaric, p-toluenesulfonic acid and the like. Particularly preferred are citric, hydrobromic, hydrochloric, maleic, phosphoric, sulfuric, and tartaric acids.

Further usable are pharmaceutically acceptable esters of the compounds according to the present invention. The term "pharmaceutically acceptable ester" refers to esters prepared from

pharmaceutically acceptable non-toxic ester groups. Most preferred the substituent R ² is an acetyl group.

Preferably, the pharmaceutical composition comprises a compound according to the invention and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof as an active ingredient, a pharmaceutically acceptable carrier and optionally other therapeutic ingredients or adjuvants. The pharmaceutical carrier can be, for example, a solid, liquid, or gas. Suitable carriers and adjuvants can be solid or liquid and correspond to the substances ordinarily employed in formulation technology for pharmaceutical formulations. Examples of solid carriers include lactose, terra alba, sucrose, talc, gelatin, agar, pectin, acacia, magnesium stearate, and stearic acid. Examples of liquid carriers are sugar syrup, peanut oil, olive oil, and water. Examples of gaseous carriers include carbon dioxide and nitrogen.

The compositions can be suitable for oral, dermal, rectal, topical, and parenteral administration.

Parenteral administration includes subcutaneous, intramuscular, and intravenous administration. The pharmaceutical compositions may be conveniently presented in unit dosage form and prepared by any of the methods well known in the art of pharmacy.

The pharmaceutical composition of the present invention can be presented as discrete unit suitable for oral administration such as capsules, cachets or tablets each containing a predetermined amount of the active ingredient. Further, the compositions can be presented as a powder, as granules, as a solution, as a suspension in an aqueous liquid, as a non-aqueous liquid, as an oil-in-water emulsion or as a water- in-oil liquid emulsion. Further, the pharmaceutical composition may be administered by controlled release means and/or delivery devices.

For compositions for oral dosage form, convenient pharmaceutical media may be employed. For example, water, glycols, oils, alcohols, flavouring agents, preservatives, colouring agents and the like may be used to form oral liquid preparations such as solutions. Carriers such as starches, sugars, microcrystalline cellulose, diluents, granulating agents, lubricants, binders, disintegrating agents, and the like may be used to form oral solid preparations such as powders, capsules and tablets. Optionally, tablets may be coated by standard aqueous or non aqueous techniques.

Pharmaceutical compositions of the present invention suitable for parenteral administration may be prepared as solutions or suspensions of the active compounds in water. A suitable excipient can be included such as, for example, hydroxypropylcellulose. Dispersions can also be prepared in glycerol, liquid polyethylene glycols, and mixtures thereof in oils. Pharmaceutical compositions of the present invention suitable for injectable use include sterile aqueous solutions or dispersions. Further, a preservative can be included to prevent the growth of microorganisms. The pharmaceutical compositions of the present invention can be in a form suitable for topical use such as, for example, an aerosol, cream, ointment, lotion, dusting powder, or the like. Further, the compositions can be in a form suitable for use in transdermal devices. The pharmaceutical composition may also be prepared in powder or liquid concentrate form. The pharmaceutical composition of the present invention can include one or more additional carrier ingredients such as diluents, buffers, flavouring agents, binders, surface-active agents, thickeners, lubricants, preservatives and the like.

The pharmaceutical composition of the present invention can comprise a compound according to general formula (I) alone or in combination with other antibiotics. The invention further relates to a pharmaceutical composition comprising as an active ingredient a combination of a compound according to general formula (I) as given above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof, and vancomycin. Preferably, the pharmaceutical composition comprises a combination of vancomycin and a compound according to general formula (I), wherein element A is a group -CH ₂ -, the substituents R ¹ , R ³ , and R ⁴ are OH, R ² is hydro gen or C(0)CH ₃ , and R ⁵ is hydro gen or P(0)(OH) ₂ . Preferably, the pharmaceutical composition comprises a combination of vancomycin and a compound selected from the group comprising the formulas (1), (2), (3) and/or (4) as indicated above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof. The pharmaceutical composition may be produced under sterile conditions using standard

pharmaceutical techniques well known to those skilled in the art.

The present invention also relates to the use of a compound according to general formula (I) as given as follows and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof:

wherein:

R ¹ is selected from the group comprising H, OH, SH and/or NH ₂ ;

R ² is selected from the group comprising hydrogen, Ci-Cio-alkyl, C ₇ -Ci ₄ -arylalkyl wherein the aryl group has 6 to 10 carbon atoms and the alkyl group has 1 to 4 carbon atoms, C(O)C ₁ -C ₁₀ -alkyl, OC(O)C ₁ -C ₁₀ -alkyl, C(O)OC ₁ -C ₁₀ -alkyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH;

R ³ is selected from the group comprising OH, SH and/or NH ₂ ;

R ⁴ is selected from the group comprising OH, SH and/or NH ₂ ;

R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ , S(0) ₂ OH, P(S)(OH) ₂ ,

P(0)OHSH, S(0) ₂ SH and/or aryloxy phosphoramidates according to general formula (II)

⁶

(II)

wherein:

R ⁶ is selected from the group comprising linear or branched Ci-C ₆ -alkyl, benzyl and/or cyclohexyl;

R ⁷ is a side chain of an amino acid selected from the group comprising hydrogen; linear or branched Ci-C ₄ -alkyl; linear or branched alkyl groups of the type -C _n H _2n -U-D wherein n is 1, 2, 3 or 4, U is selected from the group comprising O, CO, COO, CONH, S, guanidine and/or NH and D is selected from the group comprising H and/or Ci-C ₃ -alkyl; -CH ₂ -C ₆ H ₄ -Y wherein Y is selected from the group comprising OH, SH, Ci-C ₃ -alkyl and/or NH ₂ ; -CH ₂ -imidazole; -CH ₂ -indole; -CH ₂ -(furanyl-3-yl); -CH ₂ - (pyridyl-3-yl) and/or -CH ₂ -(imidazolyl-3-yl); X is selected from the group comprising CI, Br, I, Ci-C ₆ -alkyl and/or Ci-C ₆ -alkoxy;

8 8 9 8 9

A is selected from the group comprising S, NR , C=CR°R ^* and/or CR°R', wherein

R ⁸ , R ⁹ is selected, the same or each independently of the other, from the group comprising hydrogen, Ci-Cio-alkyl, C ₂ -Ci ₀ -alkenyl, C ₆ -Ci ₀ -aryl, C ₇ -Ci ₄ -arylalkyl wherein the aryl group has 6 to 10 carbon atoms and the alkyl group has 1 to 4 carbon atoms, C(0)Ci-Cio-alkyl, C(O)OCi-Ci ₀ -alkyl, C(0)NH ₂ , NH ₂ , S(0) ₂ OH and/or a linker,

for the manufacture of a medicament. The present invention also relates to the use of a compound according to general formula (I) as given above for the manufacture of a medicament for the therapeutic and/or prophylactic treatment of a bacterial infection, particularly for the manufacture of an antibiotic.

It is a particular advantage of the compounds according to the invention is that the compounds are especially usable for the manufacture of an antibiotic, particularly against the multiresistant

Staphylococcus aureus strain.

Preferably, the substituent A is selected from the group comprising S, NR ⁸ and/or CR ⁸ R ⁹ , wherein R ⁸ and R ⁹ are selected, the same or each independently of the other, from the group comprising hydrogen, Ci-C ₅ -alkyl, C ₆ -Ci ₀ -aryl, or C ₂ -C ₅ -alkenyl. In a preferred embodiment, the element A is a group -CH ₂ - and the compound has the formula (III) as indicated below and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof:

Preferably, the substituent R ¹ is a hydroxyl group. Further, the substituent R ¹ can be hydrogen. Further preferred, the substituent R ³ is a hydroxyl group. Further preferred, the substituent R ⁴ is a hydroxyl group. In a preferred embodiment of the compound according to the invention the substituents R ¹ , R ³ and R ⁴ are OH. In another preferred embodiment of the compound according to the invention the substituent R ¹ is hydrogen and the substituents R ³ and R ⁴ are OH. In a preferred embodiment, the substituent R ² is selected from the group comprising hydrogen, Ci-C ₅ - alkyl preferably methyl, ethyl or n-propyl, benzyl, Ci-C ₅ -acyl preferably C(0)CH ₃ , C(0)C ₂ H ₅ , C(0)n- propyl or C(0)iso-propyl, Ci-C ₅ -alkylester preferably OC(0)CH ₃ , OC(0)C ₂ H ₅ , OC(0)n-propyl or OC(0)iso-propyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH. Most preferred, the substituent R ² is hydrogen. Further preferred, the substituent R ² is selected from the group comprising Ci-C ₅ -alkyl preferably methyl, ethyl or n-propyl, benzyl, Ci-C ₅ -acyl preferably C(0)CH ₃ , C(0)C ₂ H ₅ , C(0)n-propyl or

C(0)iso-propyl, Ci-C ₅ -alkylester preferably OC(0)CH ₃ , OC(0)C ₂ H ₅ , OC(0)n-propyl or OC(0)iso- propyl, C(0)NH ₂ , NH ₂ and/or S(0) ₂ OH. Preferred are small alkyl, acyl and ester groups selected from methyl, ethyl, C(0)CH ₃ , C(0)C ₂ H ₅ , OC(0)CH ₃ , OC(0)C ₂ H ₅ , and benzyl. It is also preferred that the substituent R ² is selected from C(0)NH ₂ , NH ₂ or S(0) ₂ OH.

Preferably, the substituent R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ and/or aryloxy phosphoramidates according to formula (II) wherein R ⁶ is selected from the group comprising methyl, ethyl, isopropyl, cyclohexyl and benzyl, X is methoxy and R ⁷ is methyl or another side chain of an amino acid. Preferably, the substituent R ⁵ is hydrogen. Most preferred, the substituent R ⁵ is P(0)(OH) ₂ . Further preferred, the substituent R ⁵ is an aryloxy phosphoramidate according to formula (II). Preferred are aryloxy phosphoramidates wherein R ⁶ is methyl, ethyl, isopropyl, cyclohexyl or benzyl, X is methoxy and R ⁷ is methyl or another side chain of an amino acid.

The substituent R ⁷ is a side chain of an amino acid. Preferably, the substituent R ⁷ is a side chain of a naturally occurring amino acid selected from the group comprising glycine, alanine, serine, threonine, arginine, lysine, aspartic acid, glutamic acid, asparagine, glutamine, phenylalanine, tyrosine, tryptophan, leucine, valine, isoleucine, cysteine, methionine, histidine and/or proline, preferably alanine, phenylalanine, proline, valine, leucine, isoleucine, glycine, methionine, or α,α- dimethylglycine. In preferred embodiments, the substituent R ⁷ is a linear or branched alkyl groups of the type -C _n H _2n -U-D wherein n is 1, 2, 3 or 4, U is selected from the group comprising O, CO, COO, CONH, S, guanidine and/or NH, and D is selected from the group comprising H and/or methyl; -CH ₂ - C ₅ H ₄ -OH; -CH ₂ -imidazole and/or -CH ₂ -indole. Preferably, the substituent R ⁷ is a side chain of an amino acid selected from the group comprising hydrogen; linear or branched Ci-C ₄ -alkyl, most preferred methyl.

In a preferred embodiment, the substituent R ⁵ is selected from the group comprising hydrogen, P(0)(OH) ₂ and/or aryloxy phosphoramidates according to formula (II) wherein R ⁶ is methyl, ethyl, isopropyl, cyclohexyl or benzyl, X is methoxy and R ⁷ is methyl. In especially preferred embodiments, the compound is selected from the group comprising the formulas (1), (2), (3) and/or (4) as indicated above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof.

Preferably, for the manufacture of a medicament the compound is selected from the group comprising the formulas (1) and/or (2) as indicated above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof. Preferably, for the manufacture of a medicament for the therapeutic and/or prophylactic treatment of a bacterial infection, particularly for the manufacture of an antibiotic the compound is selected from the group comprising the formulas (1), (2), (3) and/or (4) as indicated above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof.

Further preferred, the compound according to general formula (I) can be part of a dimer, trimer or oligomer, formed from one compound according to the invention and at least one other compound joined together via a linker linked to element A. Preferably the linker is selected from the group comprising nucleotide linkers, polyethylene glycols, peptide linkers and/or linear or branched, saturated or unsaturated Ci-C ₅₀ -alkyl.

Preferably, a nucleotide linker has a length in the range of≥ 1 nucleotide to < 30 nucleotides, preferred in the range of≥ 2 nucleotides to < 15 nucleotides, further preferred in the range of≥ 5 nucleotides to < 15 nucleotides, more preferred in the range of≥ 10 nucleotides to < 15 nucleotides, wherein the nucleotides are selected from the group comprising guanosine, cytidine, adenosine and/or thymidine. A preferred nucleotide is adenosine. Especially preferred linkers are Poly A-linkers. Preferably, a polyethylene glycol linker comprises 1 to 15 polyethylene glycol units, preferred in the range of 1 to 10 polyethylene glycol units, more preferred in the range of 2 to 8 polyethylene glycol units. Preferred are linear polyethylene glycol (PEG) units HO-(CH ₂ CH ₂ 0) _n -H, wherein n is an integer in the range of 1 to 15, preferred in the range of 1 to 10, more preferred in the range of 2 to 8. In preferred embodiments the linker is a peptide linker, wherein the peptide linker preferably comprises amino acids selected from the group comprising glycine, alanine and/or β-alanine. Preferably, the peptide linker comprises in the range of 2 to 4 amino acids. Preferably, the peptide linker comprises β-β- alanine units. Preferably, the peptide linker comprises in the range of 2 to 4 β-alanine units. In preferred embodiments the linker is a linear or branched, saturated or unsaturated Ci-C ₄₀ -alkyl group, preferred a Ci-C ₃₀ alkyl group, more preferred a C ₂ -C ₂ o - alkyl group Preferably, the linker is an alkyl group -(CH ₂ ) _n - wherein n is an integer in the range of 1 to 40, preferred in the range of 1 to 30, further preferred in the range of 2 to 20, more preferred in the range of 2 to 18, even more preferred n is 2, 6, 12 or 18.

The compounds of the present invention can be used alone or in combination with other antibiotics. The invention further relates to the use of a compound according to general formula (I) as given above and vancomycin for the manufacture of a medicament for the therapeutic and/or prophylactic treatment of a bacterial infection, particularly for the manufacture of an antibiotic. Preferably, the element A is a group -CH ₂ -, the substituents R ¹ , R ³ , and R ⁴ are OH, R ² is hydrogen or C(0)CH ₃ , and R ⁵ is hydrogen or P(0)(OH) ₂ , more preferably, the compound is selected from the group comprising the formulas (1), (2), (3) and/or (4) as indicated above and/or racemates, enantiomers, diastereomers, solvates, hydrates, and pharmaceutically acceptable salts and/or esters thereof.

The compounds of the present invention may be prepared using a variety of processes well known by a person skilled in the art.

A further aspect of the present invention relates to a method for the preparation of phosphorylated compounds according to the invention. In a preferred embodiment, the compounds according to the invention wherein R ⁵ is P(0)(OH) ₂ may be prepared by a method comprising the steps of:

a) Providing or Preparation of a cyclohexane according to formula (IV)

b) Alkaline hydrolysis of the carbamate moiety to a l-hydroxy-2-benzylamino moiety;

c) Selective introduction of a phosphate group to the primary hydroxyl group of the hydrolysed cyclohexane of step b);

d) Reduction of the benzyl protecting groups to the respective alcohol and amine groups of the cyclohexane of step c).

The cyclohexane according to formula (IV) may be prepared using processes well known by a person skilled in the art. The term "Bn" denotes a benzyl group for the protection of the respective alcohol and amine groups.

The alkaline hydrolysis of the alkyl ester of the carbamate moiety to a l-hydroxy-2-benzylamino moiety of step b) preferably is carried out in the presence of NaOH. A preferred solvent is a mixture of ethanol and NaOH, preferably a 1 : 1 mixture of ethanol and 2 N NaOH.

In step c) a phosphate group is introduced to the primary hydroxyl group of the hydrolysed cyclohexane of step b). The phosphorylation preferably is carried out using phosphoryl chloride (POCl ₃ ), pyridine, and water in acetonitrile (CH3CN).

The reduction of the benzyl protecting groups to the respective alcohol and amine groups of the cyclohexane of step c) in step d) preferably is carried out by catalytic hydrogenation with palladium on carbon as a catalyst. A preferred solvent for the reduction is methanol. Upon reduction of the benzyl groups to the respective alcohol and amine groups of the cyclohexane step c) after introduction of a phosphate group to the primary hydroxyl group of the hydrolysed cyclohexane a phosphorylated cyclohexane is received, as for example the compound according to formula (1).

The examples which follow serve to illustrate the invention in more detail but do not constitute a limitation thereof.

The figures show:

Figure 1 in vitro activation of the self cleavage of the glmS riboswitch by the natural metabolite glucosamine-6-phosphate (GlcN6P), glucosamine (GlcN) and by the compound according to formula (1), Carba-glucosamine-6-phosphate (Carba-GlcN6P);

Figure 2 in vitro activation of the self cleavage of the glmS riboswitch by glucosamine-6- phosphate (GlcN6P), glucosamine (GlcN) and by the compound according to formula (3), Carba-glucosamine (Carba-GlcN); Figure 3 Determination of the minimal concentration for the inhibition in Staphylococcus aureus

SG511 for the compound according to formula (1), (Carba-GlcN6P), the compound according to formula (3) (Carba-GlcN), glucosamine-6-phosphate (GlcN6P), and glucosamine (GlcN); Figure 4 the growth of Staphylococcus aureus Mu50 cells in the presence of 0.04 mM (dots),

0.156 mM (triangle, peaks up), 0.312 mM (hearts), 2.5 mM (stars), 5 mM (dots), 10 mM (checks), and 20 mM (triangle, peaks down) of the compound according to formula (3) (C GlcN), 0.01 mM vancomycin (black crosses), and without compounds (w/o cpd, black squares); Figure 5 a bar diagram showing the bacterial growth after 10 h in the presence of 2.5 mM, 5 mM, 10 mM, 20 mM, 40 mM, and 80 mM of the compound according to formula (3) (C GlcN, light grey bars), 0.0025 mM vancomycin (vanco, dark grey bars), a combination of the compound according to formula (3) and 0.0025 mM vancomycin (vanco/C GlcN, grey bars), and without compounds (w/o cpd, black bars);

Figure 6 the growth curves of S. aureus Mu 50 cells in the presence of 10 mM of the compound according to formula (3) (C GlcN, light grey squares), 0.0025 mM vancomycin (vanco, dark grey squares), a combination of 10 mM of the compound according to formula (3) and 0.0025 mM vancomycin (grey squares), and no compound (2x CDM, black squares)

Unless stated otherwise, a purification of compounds was carried out using flash column

chromatography, a variant of column chromatography. Flash column chromatography was carried out using Merck silica gel 60 (40 - 63 μπι). Pressure was achieved by nitrogen. The mobile phase, column diameter (0), filling level of silica gel, and volume of fractions was adjusted to experimental conditions.

The solvents were distilled before used. Chemicals were purchased from Acros, Fluka, Merck, Sigma- Aldrich, Fisher Scientific and Glycon and used without further purification, unless stated otherwise.

The compound according to formula (3) was prepared according to the procedure according to Miyamoto, M. et al., Tetrahedron Lett. 1992, 33, 3725-3728.

Example 1

Preparation of the compound according to formula (1) (\S,2S,3R,4R,5R)-2-a ino-5- ((phosphonooxy)methyl)-cyclohexane-l,3,4-triol step 1.1 Preparation of (lS.2S.3R.4R.5R)-3.4-di-0-benzyl-2-benzylamino-1.2-N.O-carbo nyl-5- hydroxymethyl-cyclohexane- 1.3.4-triole ( 1 S,2S,3R,4R,5R)-3,4-di-0-benzyl-2-benzylamino- 1 ,2-N,0-carbonyl-5 -hydroxymethyl-cyclohexane- 1,3,4-triole was prepared according to the method of Barton et al, Tetrahedron 1990, 46, 215-230, in ten reaction steps. step 1.2 Preparation of (lS.2S.3R.4R.5R)-3.4-di-0-benzyl-2-benzylamino-5-hvdroxymeth yl- cyclohexane- 1.3.4-triole

580 mg of (lS,2S,3R,4R,5R)-3,4-di-0-benzyl-2-benzylamino-l,2-N,0-carbo nyl-5-hydroxymethyl- cyclohexane-l,3,4-triole of step 1.1 (1.23 mmol) was dissolved in 30 mL EtOH/2N NaOH (1 : 1) and stirred for 14 h under reflux. The mixture was diluted with water and extracted with EtOAc (2 x 50 mL). The organic layer was dried (Na ₂ S04) and the solvent was evaporated. Purification by flash column chromatography (petroleum ether/EtOAc 1 : 1) yielded the titled compound (400 mg, 73 %) as a colorless solid. step 1.3 Preparation of (l^'.2^'.3j?.4j?.5j?)-3.4-di-< -benzyl-2-benzylamino-5-((phosphonooxy)methyl)- cyclohexane- 1.3.4-triol

160 μΐ. POCl ₃ (1.74 mmol), 24 μΐ. H ₂ 0 (1.34 mmol), and 149 μΐ. pyridine (1.85 mmol) were dissolved in acetonitrile (2 mL) and stirred for 10 min at 0 °C. 150 mg of the compound of step 1.2 (0.34 mmol) was added and the mixture was stirred for 8.5 h at 0 °C. 4 mL Water was added and the mixture was stirred for 1 h at room temperature followed by evaporation. Purification by reversed phase high performance liquid chromatography (RP HPLC) (semi-preparative column; 30-55 % in 10 min) followed by lyophilization yielded the titled compound (40 mg, 23 %) as a colorless solid. step 1.4 Preparation of (l^'.2^'.3j?.4j?.5j?)-2-amino-5-((phosphonooxy)methyl)-cvclo hexane-1.3.4-triol To a solution of 40 mg of the compound of step 1.3 (0.068 mmol) in MeOH (2 mL) was added 10 % Pd on carbon catalyst (10 mg) and the mixture was vigorously stirred under a hydrogen atmosphere (1 atm) at room temperature for 4 h. After filtration and lyophilization, the titled compound was obtained as a colorless solid (16 mg, 98 %).

Example 2 Determination of the in vitro activation of the self cleavage of the glmS riboswitch by the compounds according to formulas (1) and (3)

The determination was performed using an in vitro preparation of the glmS riboswitch of

Staphylococcus aureus MU50.

Sample preparation

The glmS riboswitch DNA was amplified from genomic DNA of the S. aureus Mu50 strain (RKI Berlin) by standard Pfu polymerase chain reaction (PCR) using a 5 ' primer containing the T7 promoter (GAT AAT ACG ACT CAC TAT AGG GCA GTT AAA GCG CCT GTG CAA ATA, SEQ ID NO: 1) and a 3 ' primer (ATC TTA TTA ACT TTG TCC ATT AAG TCA CCC, SEQ ID NO: 2) (20 cycles, annealing temperature of 60°C, homemade Pfu enzyme). The resultant of a ΙΟΟμΙ PCR reaction was phenol/chloroform extracted and precipitated using 3M NaOAc pH 5.4 and ethanol. Pellets were resuspended in ΙΟμΙ diethylpyrocarbonate treated water (DEPC H ₂ 0) and used as template for T7 RNA polymerase-based transcription. The transcription reaction contained the following components (concentrations stated as final concentrations): transcription buffer 40mM

Hepes KOH pH 7.9, 25mM MgCl ₂ , 5mM DTT, 2.5mM of each NTP, 0.5 U/μΙ RNasin (Promega), 1.5- 3mM DNA template, 0.511/μΙ T7 RNA polymerase (homemade), DEPC H ₂ 0 ad ΙΟΟμΙ. Incubation occurred at 37°C over night and was followed by RNA work-up using PAGE (10% PAA-gel) and standard gel extraction and RNA precipitation procedures.

Hereafter, the S. aureus glmS riboswitch RNA was dephosphorylated on its 5' end using the calf intestine alkaline phosphatase (CIAP, Promega). Finally, 45pmol of dephosphorylated RNA were used for phosphorylation using gamma ² P-ATP (10 mCi/ml NEN, Zaventem, Belgium) and the T4 polynucleotide kinase (NEB). After incubation at 37°C for 30 min the reaction was passed through a G25 sepharose column (GE Healthcare) which had been equilibrated with DEPC H ₂ 0 before, to exclude unincorporated radioactive nucleotides. Eventually the RNA was PAGE purified and precipitated. The pellets were dissolved in an appropriate volume of DEPC H ₂ 0 and stored at -20°C until use.

Metabolite-induced self-cleavage assay For this assay the following components were mixed to yield the stated final concentrations: cleavage buffer (50mM Hepes pH 7.5, 200mM KC1), MgCl ₂ (lOmM), glucosamine-6 -phosphate (200μΜ), glucosamine (GlcN) (200μΜ), the compound according to formula (1) (200 μΜ) or the compound according to formula (3) (200 μΜ and 20 mM), radioactively labelled RNA (20cps) and DEPC H ₂ 0 ad ΙΟμΙ. Each reaction was prepared in a 1.5μ1 Eppendorf tube. RNA was added last, after having been heated to 85°C for 2min and slowly cooled-down to room temperature for lOmin. The cleavage reaction was then incubated at 37°C for 30 min and stopped by the addition of 5μ1 sucrose PAGE loading buffer. Samples were loaded on thin 17% PAA gels and run at 400-600V for 2-4 hours.

Irradiation of the phophorimager screen was performed over night at -80°C. The screens were read using a FujiFilm Phosphorlmager FLA 3000 and evaluated using AIDA software.

As can be seen in Fig. 1, the compound according to formula (1) (carba-GlcN6P) was shown to induce glmS-riboswitch self-cleavage very efficiently at a concentration of 200 μΜ. Concentration dependent analysis revealed an EC50-value of 6.24 ± 0.66 μΜ compared to 3.61 ± 0.39 μΜ found for glucosamine-6-phosphate (GlcN6P). As can be seen in Fig. 2, the compound according to formula (3) (carba-GlcN) also was able to induce glmS-riboswitch self-cleavage efficiently at a concentration of 200 μΜ and 20 mM.

Example 3

Determination of the minimal concentration for the inhibition in Staphylococcus aureus SG511

The determination of the minimal inhibitory concentration (MIC) of the compounds according to formula (1) (carba-GlcN6P) and formula (3) (carba-GlcN) was performed in clear, round bottom 96- well plates. For this ΙΟΟμΙ of 0.5x Mueller-Hinton media (Oxoid, 300 gm/litre dehydrated infusion from beef, 17.5 gm/litre casein hydrolysate, 1.5 gm/litre starch, pH 7.3) were put into the 12 wells. To the first well ΙΟΟμΙ of 320mM solution of carba-GlcN were added, mixed by pipetting and ΙΟΟμΙ of this mixture were transferred into the next well etc., generating a sequence final dilutions from 160mM to 0.08mM. Finally, SG511 cells that had been grown to an optical density (OD ₆₀ o) of 1 were diluted in 0.5x Mueller-Hinton media 1 : 10 000. From this dilution ΙΟΟμΙ were added to the already prepared plate leading to a final compound concentration of 80mM-0.04mM. After incubation for 10 min at RT and vivid shaking, the 96-well plate was transferred to a 37°C incubator. After 18-24h of incubation the plate was read at 600nm using a standard plate reader.

As can be seen in Fig. 3, bacterial growth was inhibited by the compounds according to the invention.

These experiments show that the carba-analogues of GlcN6P according to formulas (1) and (3) can activate the glmS-riboswitch from S. aureus. Especially the compound according to formula (1) is able to activate the metabolite-dependent glmS-riboswitch from S. aureus with almost the same potency, as does the native metabolite.

These experiments further show that since the glmS-riboswitch is involved in the regulation of early steps of cell wall biosynthesis and interference with cell wall biosynthesis represents a valuable strategy to inhibit bacterial growth, the compound according to the invention can serve as important lead structure for developing novel antibiotics.

Example 4

Determination of the growth inhibition in Vancomycin intermediate resistant Staphylococcus aureus Mu50 in sugar free medium For the preparation of 2x chemically defined medium (2xCDM), a minimal medium for

Staphylococcus aureus without glucose, for the preparation of 500 ml the following components were mixed in individual groups before being combined:

Group I

5 mg FeS0 ₄ x 7 H ₂ 0, 1 mg Fe(N0 ₃ ) ₃ x 9 H ₂ 0, and 5 mg MnS0 ₄ were dissolved in 1 ml of deionized distilled water (ddH ₂ 0).

Group IIA

100 mg L-tryptophan and 50 mg L-cysteine were dissolved in 1 ml 2N HQ at 55°C. Group IIB

100 mg L-leucin, 100 mg DL-alanin, 100 mg L-isoleucin, 100 mg L-methionine, 200 mg L-threonine, 100 mg L-arginine, 100 mg L-histidine, 100 mg L-valine, 100 mg L-lysine, and 100 mg L-glutamine were dissolved in 10 ml ddH ₂ 0.

Group IIC

100 mg L-aspartate, 100 mg L-phenylalanine, 100 mg L-serine, 100 mg L-proline, 100 mg L- hydroxyproline, 100 mg glycine, 100 mg L-glutamate, and 100 mg L-tyrosine were each dissolved in 1 ml 2.5N NaOH at 55°C.

Group III

1 mg p-aminobenzoic acid, 1 mg biotin, 2.4 mg folic acid, 4 mg nicotinamide, 10 mg a-nicotinamide adeninedinucleotide, 8 mg D-pantothenic acid, 4 mg pyridoxal HCl, 4 mg pyridoxamin-di-HCl, 8 mg riboflavine, 4 mg thiamine HCl, and 0.5 mg Cobalamine (vit. B 12) were dissolved in 10 ml ddH ₂ 0, then 2.5N NaOH were added drop-wise until the solution got clear.

Group IV

20 mg Adenine, 20 mg Guanine HCl, and 20 mg Uracil were dissolved in 3 ml 2N HCl at 90°C. Group V

200 mg K ₂ HP0 ₄ , 1000 mg KH ₂ P0 ₄ , 700 mg MgS0 ₄ x 7H ₂ 0, 7 mg CaCl ₂ x 2H ₂ 0, 4500 mg NaOAc x 3H ₂ 0, and 13 g HEPES (4-(2-hydroxyethyl)-l-piperazineethanesulfonic acid) were dissolved in 350 ml ddH ₂ 0. After preparation of the individual groups, the groups I-IV were added to group V. The volume was adjusted to 480 ml with ddH ₂ 0. The pH was adjusted to 7 using HCl followed by adjusting the volume to the final 500 ml. Before storage at 4°C the medium was sterile filtered.

The determination of the decrease in bacterial growth of Staphylococcus aureus Mu50 cells (RKI Berlin) depending on the concentration of the compound according to formula (3) (C GlcN) was performed in clear, sterile, round bottom 96-well plates with lid. Before treatment, the cells were grown in 2xCDM medium without glucose at 37°C for 24 h under vigorous shaking.

For the determination of the growth inhibition 100 μΐ of 2xCDM were put into each of 12 wells. To the first well 100 μΐ of a 320 mM solution of the compound according to formula (3) (C GlcN) were added, mixed by pipetting and 100 μΐ of this mixture were transferred into the next well etc., generating a sequence dilutions from 160 mM to 0.08 mM. Finally, Mu50 cells that had been grown to an optical density (OD ₆₀ o) of 0.8 to 1 were diluted in 2xCDM to an optical density (OD ₆₀ o) of 0.2. From this dilution 100 μΐ were added to the already prepared plate leading to a final compound concentration of 80 mM, 40 mM, 20 mM, 10 mM, 5 mM, 2.5 mM, 0.312 mM, 0.156 mM, and 0.04 mM and a final OD ₆₀ o of 0.1 per well at the beginning of the measurement. The 96 well plate was incubated at 37°C in a Tecan Sunrise plate reader, which tracks the optical density (OD ₆₀ o) in 10 minute intervals and automatically shakes the plate for one minute every two minutes. Minimal inhibitory concentration was read after 18 h to 24 h of incubation. Control cells were treated without compounds and with 0.01 mM vancomycin.

Figure 4 shows the optical density (OD ₆₀ o) of the bacterial growth of S. aureus Mu 50 cells in the presence of 0.04 mM (dots), 0.156 mM (triangle, peaks up), 0.312 mM (hearts), 2.5 mM (stars), 5 mM (dots), 10 mM (checks), and 20 mM (triangle, peaks down) of the compound according to formula (3) (C GlcN), the presence of 0.01 mM vancomycin (black crosses), and without compound (w/o cpd, black squares) over of 15 h of incubation. As can be seen in Figure 4, a concentration dependent decrease in bacterial growth was observed for increased concentrations of the compound according to formula (3). A measureable growth inhibition in sugar free medium started at 0.156 mM of the compound according to formula (3) referring to the control cells grown without compounds. A more pronounced growth inhibition was observed at concentrations of 2.5 mM, 5 mM, 10 mM, and 20 mM of the compound according to formula (3). The minimal inhibitory concentration (MIC) values repeatedly (n=3) were observed at 0.625 mM of the compound according to formula (3).

Example 5 re

investigation of synergistic effects of the compound according to formula (3) in vancomycin treatment of S. aureus Mu50

The determination of the synergistic effects of the compound according to formula (3) in vancomycin treatment in Staphylococcus aureus Mu50 cells (RKI Berlin) was performed in clear, sterile, round bottom 96-well plates with lid. Before treatment, Staphylococcus aureus Mu50 cells (RKI Berlin) were grown in sterile, 15 ml flasks containing 5ml of 2x CDM without glucose at 37°C for 24 h under vigorous shaking. For the determination of the growth inhibition 100 μΐ of 2xCDM containing 10 μΜ vancomycin were put into each of 12 wells. To the first well 100 μΐ of a 320 mM solution of the compound according to formula (3) (C GlcN) were added, mixed by pipetting and 100 μΐ of this mixture were transferred into the next well etc., generating a sequence dilutions from 160 mM to 5 mM. Finally, Mu50 cells that had been grown to an optical density (OD ₆₀ o) of 0.8 to 1 were diluted in 2xCDM to an optical density (OD ₆₀ o) of 0.2. From this dilution 100 μΐ were added to the already prepared plate leading to a final compound concentration of 80 mM, 40 mM, 20 mM, 10 mM, 5 mM, and 2.5 mM, a final

concentration of 2.5 μΜ vancomycin and a final OD ₆₀ o of 0.1 per well at the beginning of the measurement. The 96 well plate was incubated at 37°C in a Tecan Sunrise plate reader, which tracks the optical density (OD ₆₀ o) in 10 minute intervals and automatically shakes the plate for one minute every two minutes. Minimal inhibitory concentration was read after 18 h to 24 h of incubation. Control cells were treated without compounds or with 2.5 μΜ vancomycin.

Figure 5 shows a bar diagram of the optical density (OD ₆₀₀ ) of the bacterial growth after 10 h growth in the presence of concentrations of 2.5 mM, 5 mM, 10 mM, 20 mM, 40 mM, and 80 mM of the compound according to formula (3). As can be seen in Figure 5, after 10 h of bacterial growth a subinhibitory concentration of vancomycin of 0.0025 mM alone (vanco, dark grey bars) showed no change in the bacterial growth as compared to untreated cells (w/o cpd, black bars). Cells grown in the presence of a subinhibitory concentration of 0.0025 mM vancomycin and concentrations of 2.5 mM, 5 mM, 10 mM, 20 mM, 40 mM, and 80 mM of the compound according to formula (3) (vanco/C GlcN, grey bars) revealed a more prominent growth inhibition than seen for the compound according to formula (3) (C GlcN, light grey bars) alone at the same concentration.

Figure 6 shows the optical density (OD ₆₀ o) of the bacterial growth of S. aureus Mu 50 cells in the presence of 10 mM of the compound according to formula (3) (C GlcN, light grey squares), 0.0025 mM vancomycin (vanco, dark grey squares), a combination of 10 mM of the compound according to formula (3) and 0.0025 mM vancomycin (grey squares), and no compound (2x CDM, black squares) over the time period of 18 h of incubation. As can be seen in Figure 6, a subinhibitory concentration of 0.0025 mM vancomycin over the period of 18 h of incubation showed no change in the bacterial growth as compared to the untreated cells. The growth curves of aureus Mu 50 cells grown in the presence of 0.0025 mM vancomycin and 10 mM of the compound according to formula (3) revealed a more prominent growth inhibition compared to a treatment with 10 mM of the compound according to formula (3) alone.

These experiments show that a combination of the compound according to formula (3) and a subinhibitory concentration of vancomycin have a synergistic effect on the growth inhibition of bacterial cells.