Patent ID: 8637545

Claim:
A compound of the formula (I), or an organic or inorganic salt thereof, wherein n is 1, 2, 3, 4, 5 or 6, R 1 represents from one to four of the same or different substituents selected from F, Cl, Br, C 1-4 alkyl, OH, OC 1-4 alkyl, NO 2 , NHC(O)C 1-4 alkyl, NH 2 , NH(C 1-4 alkyl), N(C 1-4 alkyl) 2 ; R 2 represents OR 3 , NR 3 R 4 , or N(R 3 )COR 4 ; and R 3 and R 4 represent independently and at each occurrence H or C 1-4 alkyl.