| abstract |
Heterocyclic compounds of formula (I), wherein R 1 is carboxy or protected carboxy, R 2 is aryl which may have suitable sustituent(s), R 3 is aryl which may have suitable substituent(s), R 4 is hydrogen, lower alkyl, hydroxy or aryl, A 1 is lower alkylene, (a) is (b), etc., —A 3 — is (c), etc. and n is 0 or 1, and pharmaceutically acceptable salts thereof which are useful as a medicament. |