Patent ID: 8288385

Claim:
A compound of formula I wherein R 1 represents phenyl which is unsubstituted or mono-, di- or tri-substituted, wherein the substituents are independently selected from the group consisting of halogen, (C 1 -C 4 )alkyl and (C 1 -C 3 )fluoroalkyl; Z represents hydrogen, (C 1 -C 4 )alkyl, cyclopropyl, cyclopropylmethyl, hydroxy-(C 1 -C 3 )alkyl, carboxy-(C 1 -C 3 )alkyl, cyano-(C 1 -C 3 )alkyl, P(O)(R 6 ) 2 â€”(C 1 -C 3 )alkyl, 1H-tetrazol-5-yl-(C 1 -C 3 )alkyl or benzyl; R 2 represents cyano, â€”COOH, â€”CONH 2 , â€”COOR 3 , hydroxy-(C 1 -C 3 )alkyl, (C 1 -C 2 )alkoxy-(C 1 -C 2 )alkyl, carboxy-(C 1 -C 3 )alkyl, 1H-tetrazol-5-yl or â€”NHR 5 ; with the proviso that, if R 2 represents â€”COOR 3 , Z represents carboxy-(C 1 -C 3 )alkyl or P(O)(R 6 ) 2 â€”(C 1 -C 3 )alkyl; R a represents hydrogen or methyl; R 3 represents (C 1 -C 4 )alkyl; R 4 represents (C 1 -C 6 )alkoxy or benzyloxy; R 5 represents hydrogen or tert-butoxycarbonyl; R 6 represents hydroxy, (C 1 -C 4 )alkoxy, R 7 â€”OCH 2 Oâ€” or R 8 â€”(C 1 -C 4 )alkyl-NHâ€”; R 7 represents (C 1 -C 4 )alkylcarbonyl or (C 1 -C 4 )alkoxycarbonyl; and R 8 represents (C 1 -C 4 )alkoxycarbonyl; or a salt of such a compound.