Patent ID: 7262172

Claim:
A compound of formula (I) wherein R 1 is hydrogen; R 2 is OC(O)XR 7 or OC(O)NHXR 7 ; R 3 is hydrogen; R 4 is XR 7 ; R 5 is XR 7 , C(O)XR 7 or C(O)NHXR 7 ; R 6 is hydrogen; or R 5 and R 6 taken together with the intervening atoms form a cyclic carbonate having the following structure X is C 1-6 alkylene (optionally substituted by NR 8 R 9 ), C 3-6 alkenyl (optionally substituted by NR 8 R 9 ), or the group (CH 2 )pY(CH 2 )q wherein Y is O or NR 8 and the sum of p and q is an integer from 2 to 6; and R 7 is hydrogen, phenyl (optionally substituted by one or two groups selected from halogen, nitro, trifluoromethoxy, cyano, and 5 or 6-membered heteroaryl group), pyridyl, 3-quinolyl, 4-quinolyl, benzoxazolyl, 1,3 benzothiazolyl, 1,2,3,4-tetra hydro-quinolyl, cyclopropyl, benzimidazolyl, isoquinolyl, naphthyl or furanyl; R 8 and R 9 independently represent hydrogen or C 1-4 alkyl optionally substituted by 1 or 2 groups selected from: phenyl, optionally substituted by C 1-4 alkoxy or nitro, 5-membered heteroaryl containing 1 or 2 heteroatoms selected from oxygen, sulphur and nitrogen, hydroxy, oxo, and carboxy, or R 8 and R 9 independently represent a phenyl optionally substituted by one or two C 14 alkyl groups, or a nitrogen protecting group; or a pharmaceutically acceptable salt thereof.