Patent ID: 7728035

Claim:
A compound of general formula (I): wherein X 1 is H or COR 1 and X 2 is H or COR 2 but X 1 and X 2 are not both H; R 1 and R 2 are the same or different and are each C 1-4 alkyl substituted with R 3 , or a four to seven-membered ring which is substituted with R 8 and can contain one or more heteroatoms selected from O, S(O) n and NR 9 ; R 3 is CF 3 , OR 4 , NR 5 R 6 or S(O) n R 7 ; R 4 , R 5 , and R 6 are the same or different and are each H or C 1-4 alkyl optionally substituted with R 3 , or NR 5 R 6 is a C 4-6 heterocycloalkyl ring containing one or more heteroatoms selected from O, NR 8 and S(O) n ; each n is 0-2; R 7 is C 1-4 alkyl; R 8 is as defined for R 3 or C 1-4 alkyl substituted with R 3 or halogen; and R 9 is H or C 1-4 alkyl; or a salt thereof.