Compounds useful for treating neurodegenerative disorders

A compound of formula V:

• or a pharmaceutically acceptable salt thereof, wherein:
• each of Ring A, Ring B, Ring C, Ring D, and Ring E is independently saturated, partially unsaturated or aromatic;
• G is S, CH2, NR, or O;
• R1 and R2 are each independently halogen, R, OR, a suitably protected hydroxyl group, SR, a suitably protected thiol group, N(R)2, or a suitably protected amino group, or R1 and R2 are taken together to form a 3-7 membered saturated, partially unsaturated, or aryl ring having 0-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur;
• each R is independently hydrogen, an optionally substituted C1-6 aliphatic group, or an optionally substituted 3-8 membered saturated, partially unsaturated, or aryl ring having 0-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur, wherein:
• two R on the same nitrogen atom are optionally taken together with said nitrogen atom to form a 3-8 membered saturated, partially unsaturated, or aryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, or sulfur;
• n is 0-2;
• R3, R4, R7, and R8 are each independently selected from halogen, R, OR, a suitably protected hydroxyl group, SR, a suitably protected thiol group, SO2R, OSO2R, N(R)2, a suitably protected amino group, NR(CO)R, NR(CO)(CO)R, NR(CO)N(R)2, NR(CO)OR, (CO)OR, O(CO)R, (CO)N(R)2, or O(CO)N(R)2;
• m is 0-2;
• R5 is T-C(R′)3, T-C(R′)2C(R″)3, R, OR, a suitably protected hydroxyl group, SR, a suitably protected thiol group, SO2R, OSO2R, N(R)2, a suitably protected amino group, NR(CO)R, NR(CO)(CO)R, NR(CO)N(R)2, NR(CO)OR, (CO)OR, O(CO)R, (CO)N(R)2, or O(CO)N(R)2;
• each T is independently a valence bond or an optionally substituted straight or branched, saturated or unsaturated, C1-6 alkylidene chain wherein up to two methylene units of T are optionally and independently replaced by —O—, —N(R)—, —S—, —C(O)—, —S(O)—, or —S(O)2—;
• each R′ and R″ is independently selected from R, OR, SR, SO2R, OSO2R, N(R)2, NR(CO)R, NR(CO)(CO)R, NR(CO)N(R)2, NR(CO)OR, (CO)OR, O(CO)R, (CO)N(R)2, or O(CO)N(R)2;
• R6 is hydrogen;
• R9 and R9′ are each independently selected from halogen, R, OR, SR, or N(R)2, or R9 and R9′ are taken together to form a 3-7 membered saturated or partially unsaturated ring having 0-2 heteroatoms independently selected from nitrogen, oxygen, or sulfur;
• and
• Q is a valence bond or an optionally substituted straight or branched, saturated or unsaturated, C1-6 alkylidene chain wherein up to two methylene units of Q are optionally and independently replaced by —O—, —N(R)—, —S—, —C(O)—, —S(O)—, or —S(O)2—.