[Formula 1] Expression novel have the meanings as defined with a cell cycle kinase inhibitory activity, and X 2 and 6, X 1 R 1, R 2, R 3, R 4, R 5, R the invention, (I) compounds, their preparation, including their use as medicaments and compositions containing them.【化1】本発明は、細胞周期キナーゼ阻害性酵素活性を有する、R1、R2、R3、R4、R5、R6、X1及びX2が定義された意味を有する新規な式(I)の化合物、それらの製造、それらを含有する組成物及び薬剤としてのそれらの使用を含む。