Cancer treating compounds

A compound of formula I, or a pharmaceutically acceptable salt thereof:

• wherein:
• A represents a 5 or 6 membered ring wherein there are 3 or 4 atoms not represented in the ring and the 3 or 4 atoms are selected as follows:
• 0, 1 or 2 of the atoms are selected independently from C═O, N, NH, S, or O with the balance of the atoms being made up of CH;
• X represents NH, S or O;
• Y represents a halo group;
• R1 represents a group selected from:
• —OR4a, —NR4aR4b, substituted or unsubstituted C1-6 alkyl, substituted or unsubstituted C5-10 cycloalkyl, substituted or unsubstituted C5-10 heterocycloalkyl, substituted or unsubstituted C6-10 aryl, and substituted or unsubstituted C5-10 heteroaryl,
• wherein, when substituted, the R1 group is substituted with 1, 2, or 3 groups independently selected from:
• halo, —OR4a, —NR4aR4b, —NO2, C1-6 alkyl, C1-6 haloalkyl, C1-6 alkyl substituted with OH, C1-6 alkyl substituted with OMe, and C1-6 alkyl substituted with ═O;
• R2 represents a group selected from:
• H, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, and —C(O)—R5;
• R3 represents a group selected from:
• H, —OH, halo, C1-6 alkyl, C1-6 haloalkyl, C1-6 alkoxy, —NR6aR6b, C1-6 alkoxy substituted with C6-10 aryl and C1-6 alkyl substituted with C6-10 aryl;
• R4a and R4b are each independently selected from:
• C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, C1-6 alkyl substituted with OH, C1-6 alkyl substituted with OMe, C1-6 alkyl substituted with ═O, C1-6 alkyl substituted with a substituted or unsubstituted C6-10 aryl, —C(O)—C1-6alkyl, —(CR7aR7b)nC(O)OR8, —(CR7aR7b)nC(O)NHR8, substituted or unsubstituted C5-10 cycloalkyl, substituted or unsubstituted C5-10 heterocycloalkyl, substituted or unsubstituted C6-10 aryl, and substituted or unsubstituted C5-10 heteroaryl;
• or R4b is H;
• wherein, when substituted, the R4a and R4b group is substituted with 1 or 2 groups selected from:
• halo, OH, —NO2, C1-6 alkyl, C1-6 alkoxy, C1-6 haloalkyl, C1-6 alkyl substituted with OH, C1-6 alkyl substituted with OMe, C1-6 alkyl substituted with ═O, and —NH2;
• n is 1, 2, or 3 (preferably 1);
• R5 represents a group selected from:
• C1-6 alkyl, C2-6 alkenyl, and C2-6 alkynyl;
• R6a and R6b are each independently selected from:
• H and C1-6 alkyl;
• one of R7a and R7b is a group selected from:
• H, C1-6 alkyl and C1-6 alkyl substituted with —OH, —SH, —SMe, —NH2, —C(O)OH, —C(O)NH2, guanidine, C6-10 aryl, C6-10 aryl substituted with —OH, or C5-10 heteroaryl;
• and all other R7′ and R7b are H;
• and
• R8 represents a group selected from:
• H and C1-6 alkyl;
• provided that R1 is not —OBn when R2 is methyl.