The present invention relates to a compound represented by formula (I), a method for the preparation thereof, and a pharmaceutical composition containing the compound as an active ingredient for inhibiting histone methyltransferase such as SUV39H2.本發明有關於由式(I)所示的化合物、其製備方法以及含有此化合物,作為抑制組蛋白甲基轉移酶,例如SUV39H2的有效成分的醫藥組合物。