Patent ID: 7084270

Claim:
A compound of formula: wherein R 1 is selected from the group —H, —COR 4 , and —COOCHR 5 OCOR 4 ; R 2 and R 3 are independently selected from —H, and —OR 5 ; R 4 is selected from the group —C 1-6 alkyl, -lower alkyl substituted by up to 4 groups independently selected from —NR 5 R 6 , —SR 5 , —OR 5 , -aryl, -aryl substituted by up to 2 groups independently selected from —OR 5 and C 1-4 lower alkyl, and -heteroaryl, and -heterocycle; R 5 and R 6 are independently selected from —H, and —C 1-5 lower alkyl, or, alternatively, —NR 5 R 6 can form a ring having 3 to 7 atoms, said ring optionally including one or more additional N or O atoms: or the pharmaceutically acceptable salts thereof.