[Object] The present invention provides a novel oral low-molecular compound acting as an antagonist of the calcium receptor and having high safety.[Solution] The provided is a compound of formula (I) or a pharmaceutically acceptable salt thereof.[wherein the substitutents are defined as below: R1and R2are independently hydrogen and the like； R3is methyl, ethyl and the like； Z is carboxy group and the like； Ar is phenyl and the like； A is a single bond and the like； n is 0 or； and m is an integral of 0~6.]本發明課題是提供顯示鈣受體拮抗作用，且安全性高可經口投與之新穎低分子化合物。解決手段為具有一般式(I)之化合物或其藥理上容許的鹽。[式中，各取代基定義如下。R1及R2：氫原子等。R3：甲基、乙基等。Z：羧基。Ar：苯基等。A：單鍵等。n：0或1。m：0-6之整數。]
