Compounds and compositions for the treatment of parasitic disease

A compound of Formula Ib:

• in which:
• Rb is selected from hydrogen and C1-4alkyl;
• R4 is selected from hydrogen and C1-6alkyl;
• R5 is selected from hydrogen and C1-6alkyl;
• or R4 and R5 together with the carbon atom to which R4 and R5 are attached forms C3-8cycloalkyl;
• R6 is selected from C6-10aryl, C3-8cycloalkyl and a saturated, unsaturated or partially unsaturated 5-9 member mono or fused heterocyclic ring containing up to three heteroatoms or groups selected from N, C(O), NR30, S(O)0-2 and O;
• wherein R30 is selected from hydrogen and C1-6alkyl;
• wherein said aryl or heterocyclic of R6 is optionally substituted by 1 to 3 radicals independently selected from halo, hydroxy, C1-6alkyl and C1-6alkoxy;
• R7 is selected from hydrogen and C1-3alkyl;
• R8 is selected from C1-10alkyl, C6-10aryl-C0-4alkyl, C3-8cycloalkyl and a saturated, unsaturated or partially unsaturated 5-9 member mono or fused heterocyclic ring containing up to three heteroatoms or groups selected from N, C(O), NR30, S(O)0-2 and O;
• wherein R30 is selected from hydrogen and C1-6alkyl;
• wherein said aryl or heterocyclic of R8 is optionally substituted by 1 to 3 radicals independently selected from halo, cyano, hydroxy, C1-6alkyl, halo-substituted-C1-6alkyl, halo-substituted-C1-6alkoxy, C1-6alkoxy, —C(O)OR18, —S(O)0-2R18, —C(O)NHR18, —NHS(O)0-2R18, phenyl and a saturated, unsaturated or partially unsaturated 5-6 member heterocyclic ring containing up to three heteroatoms or groups selected from N, C(O), NR30, S(O)0-2 and O;
• wherein R30 is selected from hydrogen and C1-6alkyl;
• wherein said aryl or heterocyclic substituent of R8 is optionally substituted by 1 to 3 radicals independently selected from halo, cyano, hydroxy, C1-6alkyl and halo-substituted-C1-6alkyl;
• wherein R18 is selected from hydrogen and C1-6alkyl;
• R9 is selected from hydrogen and C1-6alkyl;
• R10 is selected from hydrogen and C1-6alkyl;
• R11 is selected from hydrogen and C1-6alkyl;
• R12 is selected from hydrogen and C1-6alkyl;
• or R11 and R12 combine to form C(O);
• or
• the pharmaceutically acceptable salts thereof.