Compounds for treating proliferative disorders

A compound represented by formula (I):

• or a tautomer or a pharmaceutically acceptable salt thereof, wherein:
• Z1 are Z2 are independently O, S, Se, Te, Po, NR13, PR13, AsR13, SbR13 or BiR13;
• Z3 and Z4 are independently O, S, Se, Te, Po, N(R13)m, P(R13)m, As(R13)m, Sb(R13)m, or Bi(R13);
• Y is a covalent bond, or a substituted or unsubstituted C1-C6 alkylene group;
• or,
• Y is —C(R3)p— and taken together with both >C═Z3 and >C═Z4 groups to which it is bonded, forms an optionally substituted monocyclic aromatic group;
• R1 and R2 are independently an optionally substituted alkyl, an optionally substituted alkenyl, an optionally substituted alkynyl, an optionally substituted cycloalkyl, an optionally substituted cycloalkenyl, an optionally substituted heterocyclyl, an optionally substituted aryl, an optionally substituted heteroaryl, halo, nitro, cyano, guanidino, —OR17, —NR19R20, —C(O)R17, —C(O)OR17, —OC(O)R17, —C(O)NR19R20, —NR18C(O)R17, —OP(O)(OR17)2, —SP(O)(OR17)2, —SR17, —S(O)pR17, —OS(O)pR17, —S(O)pOR17, —NR18S(O)pR17, or —S(O)pNR19R20;
• R3 and R4 are independently —H, an optionally substituted alkyl, an optionally substituted alkenyl, an optionally substituted alkynyl, an optionally substituted cycloalkyl, an optionally substituted cycloalkenyl, an optionally substituted heterocyclyl, an optionally substituted aryl or an optionally substituted heteroaryl;
• one of R′5 or R′6 is —C(O)R35 and the other is —H, —C(O)R35, an optionally substituted alkyl, an optionally substituted alkenyl, an optionally substituted alkynyl, an optionally substituted cycloalkyl, an optionally substituted cycloalkenyl, an optionally substituted heterocyclyl, an optionally substituted aryl or an optionally substituted heteroaryl;
• R13 for each occurrence is, independently, —H, —OR17, —NR19R20, —C(O)R17, —C(O)OR17, —OC(O)R17, —C(O)NR19R20, —NR18C(O)R17, —OP(O)(OR17)2, —SP(O)(OR17)2, —SR17, —S(O)pR17, —OS(O)pR17, —S(O)pOR17, —NR18S(O)pR17, or —S(O)pNR19R20, an optionally substituted alkyl, an optionally substituted alkenyl, an optionally substituted alkynyl, an optionally substituted cycloalkyl, an optionally substituted cycloalkenyl, an optionally substituted heterocyclyl, an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted aralkyl, or an optionally substituted heteraralkyl;
• R17 and R18, for each occurrence, are, independently, —H, an optionally substituted alkyl, an optionally substituted alkenyl, an optionally substituted alkynyl, an optionally substituted cycloalkyl, an optionally substituted cycloalkenyl, an optionally substituted heterocyclyl, an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted aralkyl, or an optionally substituted heteraralkyl;
• R19 and R20, for each occurrence, are independently —H, an optionally substituted alkyl, an optionally substituted alkenyl, an optionally substituted alkynyl, an optionally substituted cycloalkyl, an optionally substituted cycloalkenyl, an optionally substituted heterocyclyl, an optionally substituted aryl, an optionally substituted heteroaryl, an optionally substituted aralkyl, or an optionally substituted heteraralkyl;
• or R19 and R20, taken together with the nitrogen to which they are attached, form an optionally substituted heterocyclyl or an optionally substituted heteroaryl;
• R35 is —H, an optionally substituted alkyl, an optionally substituted alkenyl, an optionally substituted alkynyl, an optionally substituted cycloalkyl, an optionally substituted cycloalkenyl, an optionally substituted heterocyclyl, an optionally substituted aryl or an optionally substituted heteroaryl;
• m is 0 or 1;
• p is 1 or 2;
• and
• with the proviso that
• when Z1 and Z2 are both O or both S and Z3 and Z4 are both N(R13)m, then Y taken together with both >C═Z3 and >C═Z4 does not form not an optionally substituted pyrimidine ring or an optionally substituted pyrazole ring.