Patent ID: 7176203

Claim:
A compound of formula I, or a pharmaceutically acceptable salt thereof: wherein: Z represents a five-membered heteroaromatic ring selected from furan, thiophene, pyrrole, oxazole, thiazole, isoxazole, isothiazole, imidazole, pyrazole, oxadiazole, thiadiazole, triazole and tetrazole, which is unsubstituted or substituted; or Z represents a six-membered heteroaromatic ring selected from pyridine, pyrazine, pyrimidine and pyridazine, which is unsubstituted or substituted; R 1 represents hydrogen, hydrocarbon, a heterocyclic group, halogen, cyano, trifluoromethyl, nitro, —OR a , —SR a , —SOR a , —SO 2 NR a R b , —NR a R b , —NR a COR b , —NR a CO 2 R b , —COR a , —CO 2 R a , —CONR a R b or —CR a ═NOR b ; and R a and R b independently represent hydrogen, hydrocarbon or a heterocyclic group.