Patent ID: 7166725

Claim:
A compound of formula Ia or a pharmaceutically acceptable salt or solvate thereof: wherein A is hydrogen, alkyl or M + ; M is aluminum, calcium, lithium, magnesium, potassium, sodium, zinc or a mixture thereof; Z is O; R 1 and R 2 are independently selected from hydrogen, alkyl, hydroxy, alkoxy, aryl, acyl, halo, cyano, haloalkyl, NHCOOR 5 and SO 2 NH 2 ; R 5 is aryl, arylalkyl, heteroaryl or heteroarylalkyl; R 3a and R 4a are independently selected from alkyl, hydroxy, alkoxy, aryl, acyl, halo, cyano, haloalkyl, NHCOOR 5 and SO 2 NH 2 with the proviso that not all of R 1 , R 2 , R 3a and R 4a are fluoro.