Aminopyrimidine compound as CDK2/4/6 triple inhibitor

A compound represented by formula (I) or a pharmaceutically acceptable salt thereof,

• wherein,
• T is N or CH;
• R1 is
• R2 and R3 are each independently H, F, Cl, Br, I, —CN, —OH, C1-3 alkoxy or C1-3 alkyl, wherein the C1-3 alkoxy and the C1-3 alkyl are optionally substituted with 1, 2 or 3 substituents independently selected from F, Cl, Br, —CN, —OH and —NH2;
• or R2 and R3 are joined together with the carbon atom to which they are attached form C3-5 cycloalkyl, wherein the C3-5 cycloalkyl is optionally substituted with 1, 2 or 3 Rb;
• each Rb is independently H, F, Cl, Br, I, —CN, —OH, C1-3 alkoxy, C1-3 alkyl or C1-3 haloalkyl;
• R4 and R5 are each independently H, F, Cl, Br, I, —CN, —OH, C1-3 alkoxy or C1-3 alkyl, wherein the C1-3 alkoxy and the C1-3 alkyl are optionally substituted with 1, 2 or 3 substituents independently selected from F, Cl, Br, —CN, —OH and —NH2;
• or R3 and R4 are joined together with the carbon atom to which they are attached form C3-5 cycloalkyl, wherein the C3-5 cycloalkyl is optionally substituted with 1, 2 or 3 Rc;
• each Rc is independently H, F, Cl, Br, I, —CN, —OH, C1-3 alkoxy, C1-3 alkyl or C1-3 haloalkyl;
• R6 is H, F, Cl, Br, I, —CN, —OH, C1-3 alkoxy, C1-3 alkyl or C1-3 haloalkyl;
• R7 is —NH2, C1-3 alkylamino, C1-6 alkyl, C3-5 cycloalkyl, 4- to 6-membered heterocycloalkyl, 5- to 6-membered heteroaryl or phenyl, wherein the C1-6 alkyl, the C3-5 cycloalkyl, the 4- to 6-membered heterocycloalkyl, the 5- to 6-membered heteroaryl and the phenyl are optionally substituted with 1, 2 or 3 Rd;
• each Rd is independently H, F, Cl, Br, I, —CN, —OH, C1-3 alkoxy or C1-3 alkyl, wherein the C1-3 alkoxy and the C1-3 alkyl are optionally substituted with 1, 2 or 3 substituents independently selected from F, Cl, Br, —CN, —OH and —NH2;
• n is 0, 1 or 2;
• the 4- to 6-membered heterocycloalkyl and the 5- to 6-membered heteroaryl respectively comprise 1, 2, 3 or 4 heteroatoms independently selected from N, —O— and —S—.