Tylosin derivatives and method for preparation thereof

1. A compound represented by the formula (IIa):

or a pharmaceutically acceptable salt, ester, prodrug or solvate thereof;

wherein, R 11 and R 12 are each independently selected from

hydrogen;

—CHO;

C 1 -C 6 —X, wherein X is selected from the group consisting of hydroxyl or protected hydroxyl, halogen, and N 3 ;

CN;

C1-C6-alkyl, optionally substituted with one or more substituents selected from the group consisting of halogen, aryl, substituted aryl, heterocyclic and substituted heterocyclic;

C2-C6-alkenyl, optionally substituted with one or more substituents selected from the group consisting of halogen, aryl, substituted aryl, heterocyclic and substituted heterocyclic;

C2-C6-alkynyl, optionally substituted with one or more substituents selected from the group consisting of halogen, aryl, substituted aryl, heterocyclic and substituted heterocyclic;

C3-C14 cycloalkyl

substituted C3-C14-cycloalkyl;

aryl;

substituted aryl;

heterocyclic;

substituted heterocyclic;

and wherein at least R 11 or R 12 is C1-C6-alkyl, optionally substituted with one or more substituents selected from the group consisting of halogen, aryl, substituted aryl, heterocyclic and substituted heterocyclic; and

wherein R 5 is

hydroxyl.

2. The compound of claim 1 , wherein:

at least R 11 or R 12 is C1-C6-alkyl, substituted with one substituent selected from the group consisting of heterocyclic and substituted heterocyclic.

3. A method for treating or preventing bacterial infections or disorders associated with bacterial infections in an animal, wherein the method comprises administering to the animal a therapeutically effective amount of the compound according to claim 1 .

4. A pharmaceutical or veterinary composition comprising a compound according to claim 1 and at least one pharmaceutically acceptable carrier.

5. The pharmaceutical or veterinary composition of claim 4 for use in the treatment or prevention of bacterial infections or disorders associated with bacterial infections in an animal.

6. A method for treating or preventing bacterial infections or disorders associated with bacterial infections in an animal, wherein the method comprises administering to the animal a therapeutically effective amount of the composition according to claim 4 .

7. The compound of claim 1 , wherein at least R 11 or R 12 is C1-C3-alkyl, substituted with one substituent selected from the group consisting of heterocyclic and substituted heterocyclic.

8. The compound of claim 1 , wherein at least R 11 or R 12 is C1-C3-alkyl, substituted with a 1,2,3-triazole substituted at position 4 with one substituent selected from the group consisting of heterocyclic and substituted heterocyclic.

9. The compound of claim 1 , wherein one of R 11 and R 12 is C1-C6-alkyl, substituted with one substituent selected from the group consisting of heterocyclic and substituted heterocyclic, and the other one of R 11 and R 12 is

hydrogen or

C1-C6-alkyl, optionally substituted with one or more substituents selected from the group consisting of halogen, aryl, substituted aryl, heterocyclic and substituted heterocyclic.

10. A compound of claim 1 , wherein R 11 or R 12 is C1-C3-alkyl, substituted with one substituent selected from the group consisting of heterocyclic and substituted heterocyclic, and the other one of R 11 and R 12 is

hydrogen or

C1-C3-alkyl, optionally substituted with one or more substituents selected from the group consisting of halogen, aryl, substituted aryl, heterocyclic and substituted heterocyclic.

11. A compound of claim 1 , wherein one of R 11 and R 12 is C1-C2-alkyl, substituted with a 1,2,3-triazole substituted at position 4 with one substituent selected from the group consisting of heterocyclic and substituted heterocyclic, and the other one of R 11 and R 12 is

hydrogen or

C1-C2-alkyl, optionally substituted with one substituent selected from the group consisting of aryl and substituted aryl.