Derivatives of 4,5-diariloxazol.

HETEROCYCLIC COMPOUNDS OF FORMULA (I) WHERE R 1 is carboxy or protected carboxy, R {SUP, 2} is aryl which may have substituent (S) PROPER (S), R {SUP, 3} is aryl which may have substituent (S ) PROPER (S), A {SUP, 1} is lower alkylene, A SUP {2} is lower alkylene and -Q- or cake ES (II), etc., and their pharmaceutically acceptable salts which are useful as MEDICINES.