Pyridone derivatives for the treatment of viral infections and further diseases

A compound of formula (I)

• or a pharmaceutically acceptable salt, solvate or polymorph thereof, wherein
• R1 is C1-6 alkyl, optionally substituted by one or more substituents independently selected from the group consisting of aryl, halogen, OH, —NH2, —CO2H, CO2C1-3alkyl, —C(O)NHC1-3alkyl, C(O)NHSO2C1-3alkyl, C1-3 alkyl, C3-6 cycloalkyl, SO2C1-3 alkyl, —S(O)C1-3alkyl, —SO2NHC1-3 alkyl, heterocycle and —CN;
• R2, R3, R4, and R5 are each independently selected from the group consisting of hydrogen, halogen, C1-3 alkyl, C1-3 alkoxy, C3-6 cycloalkyl, aryl, —CF3 and heterocycle;
• or wherein
• R2 is fused with R3 to form a ring structure,
• R3 is fused with R4 to form a ring structure or
• R4 is fused with R5 to form a ring structure.