CDK inhibitors

A compound of formula:

• or a pharmaceutically acceptable salt thereof, wherein:
• Z is —(CH2)x— wherein x is 1, 2, 3 or 4 or —O—(CH2)z— wherein z is 2, 3 or 4;
• each X is independently CH or N;
• each of R and R8 are independently H, C1-C3 alkyl or haloalkyl;
• each R1 is independently aryl, alkyl, cycloalkyl or haloalkyl, wherein each of said alkyl, cycloalkyl and haloalkyl groups optionally includes O or N heteroatoms in place of a carbon in the chain and two R1's on adjacent ring atoms or on the same ring atom together with the ring atom(s) to which they are attached optionally form a 3-8-membered cycle;
• y is 0, 1, 2, 3 or 4;
• R2 is -(alkylene)m-heterocyclo, -(alkylene)m-heteroaryl, -(alkylene)m-NR3R4, -(alkylene)m-C(O)—NR3R4;
• -(alkylene)m-C(O)—O-alkyl;
• -(alkylene)m-O—R5, -(alkylene)m-S(O)n—R5, or -(alkylene)m-S(O)n—NR3R4 any of which may be optionally independently substituted with one or more Rx groups as allowed by valance, and wherein two Rx groups bound to the same or adjacent atom may optionally combine to form a ring and wherein m is 0 or 1 and n is 0, 1 or 2;
• R3 and R4 at each occurrence are independently:
• (i) hydrogen or
• (ii) alkyl, cycloalkyl, heterocyclo, aryl, heteroaryl, cycloalkylalkyl, heterocycloalkyl, arylalkyl, or heteroarylalkyl any of which may be optionally independently substituted with one or more Rx groups as allowed by valance, and wherein two Rx groups bound to the same or adjacent atom may optionally combine to form a ring;
• or R3 and R4 together with the nitrogen atom to which they are attached may combine to form a heterocyclo ring optionally independently substituted with one or more Rx groups as allowed by valance, and wherein two Rx groups bound to the same or adjacent atom may optionally combine to form a ring;
• R5 and R5* at each occurrence is:
• (i) hydrogen or
• (ii) alkyl, alkenyl, alkynyl, cycloalkyl, heterocyclo, aryl, heteroaryl, cycloalkylalkyl, heterocycloalkyl, arylalkyl, or heteroarylalkyl any of which may be optionally independently substituted with one or more Rx groups as allowed by valance;
• Rx at each occurrence is independently, halo, cyano, nitro, oxo, alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heterocyclo, aryl, heteroaryl, arylalkyl, heteroarylalkyl, cycloalkylalkyl, heterocycloalkyl, -(alkylene)m-OR5, -(alkylene)m-O-alkylene-OR5, -(alkylene)m-S(O)n—R5, -(alkylene)m-NR3R4, -(alkylene)m-CN, -(alkylene)m-C(O)—R5, -(alkylene)m-C(S)—R5, -(alkylene)m-C(O)—OR5, -(alkylene)m-O—C(O)—R5, -(alkylene)m-C(S)—OR5, -(alkylene)m-C(O)-(alkylene)m-NR3R4, -(alkylene)m-C(S)—NR3R4, -(alkylene)m-N(R3)—C(O)—NR3R4, -(alkylene)m-N(R3)—C(S)—NR3R4, -(alkylene)m-N(R3)—C(O)—R5, -(alkylene)m-N(R3)—C(S)—R5, -(alkylene)m-O—C(O)—NR3R4, -(alkylene)m-O—C(S)—NR3R4, -(alkylene)m-SO2—NR3R4, -(alkylene)m-N(R3)—SO2—R5, -(alkylene)m-N(R3)—SO2—NR3R4, -(alkylene)m-N(R3)—C(O)—OR5)-(alkylene)m-N(R3)—C(S)—OR5, or -(alkylene)m-N(R3)—SO2—R5;
• wherein:
• said alkyl, haloalkyl, alkenyl, alkynyl, cycloalkyl, cycloalkenyl, heterocyclo, aryl, heteroaryl, arylalkyl, heteroarylalkyl, cycloalkylalkyl, and heterocycloalkyl groups may be further independently substituted with one or more -(alkylene)m-CN, -(alkylene)m-OR5*, -(alkylene)m-S(O)n—R5*, -(alkylene)m-NR3*R4*, -(alkylene)m-C(O)—R5*, -(alkylene)m-C(═S)R5*, -(alkylene)m-C(═O)OR5*, -(alkylene)m-OC(═O)R5*, -(alkylene)m-C(S)—OR5*, -(alkylene)m-C(O)—NR3*R4*, -(alkylene)m-C(S)—NR3*R4*, -(alkylene)m-N(R3*)—C(O)—NR3*R4*, -(alkylene)m-N(R3*)—C(S)—NR3*R4*, (alkylene)m-N(R3*)—C(O)—R5*, -(alkylene)m-N(R3*)—C(S)—R5*, -(alkylene)m-O—C(O)—NR3*R4*, -(alkylene)m-O—C(S)—NR3*R4*, -(alkylene)m-SO2—NR3*R4*, -(alkylene)m-N(R3*)—SO2—R5*, -(alkylene)m-N(R3*)—SO2—NR3*R4*, -(alkylene)m-N(R3*)—C(O)—OR5*, -(alkylene)m-N(R3*)—C(S)—OR5*, or -(alkylene)m-N(R3*)—SO2—R5*,
• n is 0, 1 or 2, and
• m is 0 or 1;
• and
• R3* and R4* at each occurrence are independently:
• (i) hydrogen or
• (ii) alkyl, alkenyl, alkynyl cycloalkyl, heterocyclo, aryl, heteroaryl, cycloalkylalkyl, heterocycloalkyl, arylalkyl, or heteroarylalkyl any of which may be optionally independently substituted with one or more Rx groups as allowed by valance;
• or R3* and R4* together with the nitrogen atom to which they are attached may combine to form a heterocyclo ring optionally independently substituted with one or more Rx groups as allowed by valance, and
• R6 is a lower alkyl or absent.