Prolyl Hydroxylase Inhibitors

A a compound of formula (I):

• wherein:
• R1 is —NR7R8 or —OR9;
• R2, R3, R4, R5, and R6 are each independently selected from the group consisting of hydrogen, nitro, cyano, halogen, —C(O)R12, —C(O)OR12, —OR12, —SR12, —S(O)R12, —S(O)2R12, —NR10R11, —CONR10R11, —N(R10)C(O)R12, —N(R10)C(O)OR12, —OC(O)NR10R11, —N(R10)C(O)N10R11, —P(O)(OR12)2, —SO2NR10R11, —N(R10)SO2R12, C1-C10 alkyl, C1-C10 alkenyl, C1-C10 alkynyl, C3-C8 cycloalkyl, C3-C8 heterocycloalkyl, C5-C8 cycloalkenyl, aryl, and heteroaryl;
• R7 and R8 are each independently selected from the group consisting of hydrogen, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, C3-C6 cycloalkyl, C3-C6 heterocycloalkyl, aryl, and heteroaryl;
• R9 is hydrogen, or a cation, or C1-C4 alkyl;
• R10 and R11 are each independently selected from the group consisting of hydrogen, C1-C10 alkyl, C3-C8 cycloalkyl, alkyl-C3-C8 cycloalkyl, C3-C8 heterocycloalkyl, C1-C10 alkyl-C3-C8 heterocycloalkyl, aryl, C1-C10 alkyl-aryl, heteroaryl, C1-C10 alkyl-heteroaryl, —CO(C1-C4 alkyl), —CO(C3-C6 cycloalkyl), —CO(C3-C6 heterocycloalkyl), —CO(aryl), —CO(heteroaryl), and —SO2(C1-C4 alkyl);
• or R10 and R11 taken together with the nitrogen to which they are attached form a 5- or 6- or 7-membered saturated ring optionally containing one other heteroatom which is oxygen, nitrogen or sulphur;
• each R12 is independently selected from the group consisting of hydrogen, C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, —CO(C1-C4 alkyl), —CO(aryl), —CO(heteroaryl), —CO(C3-C6 cycloalkyl), —CO(C3-C6 heterocycloalkyl), —SO2(C1-C4 alkyl), C3-C8 cycloalkyl, C3-C8 heterocycloalkyl, aryl, C1-C10 alkyl-aryl, heteroaryl, and C1-C10 alkyl-heteroaryl;
• any carbon or heteroatom of R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, or R12 is unsubstituted or, where possible, is substituted with one or more substituents independently selected from C1-C6 alkyl, aryl, heteroaryl, halogen, —OR12, —NR10R11 cyano, nitro, —C(O)R12, —C(O)OR12, —SR12, —S(O)R12, —S(O)2R12, —CONR10R11, —N(R10)C(O)R12, —N(R10)C(O)OR12, —OC(O)NR10R11, —N(R10)C(O)NR10R11, —SO2NR10R11, —N(R10)SO2R12, C1-C10 alkenyl, C1-C10 alkynyl, C3-C8 cycloalkyl, C3-C8 heterocycloalkyl, C5-C8 cycloalkenyl, aryl or heteroaryl, wherein R10, R11, and R12 are the same as defined above;
• or a pharmaceutically acceptable salt or solvate thereof.