The present invention relates to a compound of Formula (I) and the manufacturing method(s) thereof and the use thereof:Formula (I) ##STR00001## wherein: Ar is a nitrogen-containing heteroaromatic ring group; X and Z are each a carbon atom, and so on; Y is CO, and so on; R.sub.1 is a hydrogen atom, and so on; R.sub.2 and R.sub.3 are each a hydrogen atom, and so on; R.sub.4 and R.sub.5 are each a hydrogen atom, and so on; and the formula is a single bond or a double bond.According to the present invention, the compound of the present invention can provide Cdk4 and/or Cdk6 inhibitors for treating malignant tumors, because the compounds of the present invention exhibit a prominent growth inhibitory activity against tumor cells.