Patent ID: 7569602

Claim:
A compound of formula (I): or a salt, hydrate or chemically protected form thereof, wherein: either R 2 is H or an optionally substituted C 1-4 alkyl group and R 5 is an optionally substituted C 5-7 aryl; or R 5 is H or an optionally substituted C 1-4 alkyl group and R 2 is an optionally substituted C 5-7 aryl; m and n can be 0 or 1, and m+n=1 or 2 R N is H or optionally substituted C 1-4 alkyl R 3 is either: carboxy or tetrazole-5-yl with the proviso that the compound in which R 3 is carboxy, n is 0, m is 1, R N is H, R 2 is methyl and R 5 is phenyl is excluded.