Patent ID: 8299069

Claim:
A compound according to formula (I) or a pharmaceutically acceptable salt thereof: wherein: R 1 , R 2 , R 3 , R 4 are each independently selected from the group consisting of hydrogen, halogen, alkyl, aryl, heteroaryl, —OR 5 , —O[CH 2 CH 2 O] r R 7 , —NR 5 R 6 , —COR 5 and —NR 5 COR 6 , wherein said aryl or heteroaryl is further substituted by one or more groups selected from the group consisting of alkyl, alkoxyl and halogen; R 5 and R 6 are each independently selected from the group consisting of hydrogen and alkyl, wherein said alkyl is further substituted by one or more groups selected from the group consisting of aryl, heteroaryl, haloaryl, hydroxyl, alkoxyl, aryloxyl, carboxylic acid and carboxylic ester; R 7 is hydrogen or alkyl; and r is an integer from 1 to 6.