Oxazole compounds as prostaglandin e2 agonists or antagonists

Abstract From the Canadian patent

Oxazole compounds of formula (I), wherein R1 is aryl which may be substituted with halogen(s), R2 is aryl which may be substituted with halogen(s) X is , single bond, (a) or SO2, R3 and R4 are independently hydrogen or suitable substituent, (wherein X is (a), neither R3 nor R4 is hydrogen) R3 and R4 may , be linked together to form (b) (b) is N-containing heterocyclic group which may be substituted with one or more suitable substituent(s) R5 is hydrogen, etc. A1 is lower alkylene or single bond (c) is cyclo(C3-C9)alkane or , cyclo(C5-C9)alkene or a pro-drug thereof, or a pharmaceutically acceptable salt thereof, which are useful as medicament.