Tylosin derivatives and method for preparation thereof

A compound represented by the formula (IIa):

• or a pharmaceutically acceptable salt, ester, prodrug or solvate thereof;
• wherein, R11 and R12 are each independently selected from
• hydrogen;
• —CHO;
• C1-C6—X, wherein X is selected from the group consisting of hydroxyl or protected hydroxyl, halogen, and N3;
• 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-cyclocyclic;
• substituted C3-C14-cycloalkyl;
• aryl;
• substituted aryl;
• heterocyclic;
• substituted heterocyclic;
• or R11 and R12 taken with the nitrogen atom to which they are connected form N3 or a 3- to 7-membered ring which may optionally contain a hetero function selected from the group consisting of —O—, —NH—, —N(C1-C6-alkyl)-, —N(aryl)-, —N(heteroaryl)-, —S—, —S(O)— and —S(O)2—;
• C3-C14 cycloalkyl;
• and
• wherein R5 is
• hydrogen;
• hydroxyl;
• protected hydroxyl;
• halogen;
• —N3;
• or
• N—Y2, wherein each Y is independently selected from the group consisting of hydrogen and C1-C6-alkyl, or the two Y taken with the nitrogen atom to which they are connected form a 3- to 7-membered ring.