Compounds of formula (I) or their medicinal salts are provided, wherein R1, R2, R3, R4, R5 and N, as defined herein, have been shown to be useful in the treatment of PRC2  ̄ mediated diseases or disorders.提供了式(I)化合物或其可藥用鹽,其中R1、R2、R3、R4、R5和n如本文所定義,已經證明它們可用於治療PRC2‑介導的疾病或障礙。