The present invention relates to a compound of Formula (I) and the manufacturing method(s) thereof and the use thereof:

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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; R₁ is a hydrogen atom, and so on; R₂ and R₃ are each a hydrogen atom, and so on; R₄ and R₅ 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.