Provided are a compound which is superior in metabolicstability, and selectively binds to an EP4 receptor, and amedicament containing same. It has been found that a compoundrepresented by the formula (1):(See Formula 1)wherein R1 and R2 are each independently a hydrogen atom or astraight chain alkyl group having a carbon number of 1 - 3, R3is a hydrogen atom, an alkyl group having a carbon number of 1- 4, an alkoxyalkyl group, an aryl group, a halogen atom or ahaloalkyl group, or a pharmaceutically acceptable salt thereof,has, unlike known PGI2 analogs, a selective EP4 agonist action,and therefore, a medicament containing the compound is usefulfor the prophylaxis and/or treatment of immune diseases,cardiovascular diseases, cardiac diseases, respiratorydiseases, ophthalmic diseases, renal diseases, hepaticdiseases, bone diseases, diseases of the digestive tract,neurological diseases, skin diseases and the like.
