Compositions and methods for the prevention and/or treatment of mitochondrial disease, including Friedreich's ataxia

A compound of formula E-G, or pharmaceutically acceptable salts, stereoisomers, mixtures of stereoisomers, tautomers, hydrates, and/or solvates thereof, wherein E is 21 or 22:

• and G is 23 or 24:
• wherein,
• J is O, S or N—R11;
• K is absent or —(CR12R13)—;
• L is —(CR12R13)—;
• each W is independently C (carbon) or N (nitrogen) and wherein for each use of WW, the bond between each W can be a single bond or double bond and further provided that if a single bond, each C (carbon) atom will have a hydrogen atom linked hereto in addition to one of R4, R5, R6 or R7 and in either case each of R4, R5, R6 and R7 attached thereto is independently selected from H, D, F, Cl, Br, I, C1-C6 alkyl and C1-C6 alkoxy, and if W is N (nitrogen), each of R4, R5, R6 and R7 attached thereto is independently absent (if WW is a double bond) or selected from H, D and C1-C6 alkyl (if WW is a single bond);
• each Q is independently a group of formula —(CR12R13)-, O or Si provided that each O and each Si is not directly bonded to O or Si;
• each of R1, R2 and R3 is independently H, D, F, Cl, Br, I, C1-C6 alkyl or C1-C6 alkoxy;
• or R1 and R2 together form a 5-membered carbocyclic ring, a 5-membered heterocyclic ring, a 5-membered aromatic or heteroaromatic ring, or a 6-membered heterocyclic ring;
• each R8′, R9′ and R10′ is independently a C1-C4 alkyl;
• or taken together R8′ and R9′ form a 3-, 4-, 5-, 6- or 7-membered carbocyclic or heterocyclic ring;
• R11 is H, D or C1-C6 alkyl;
• each of R12 and R13 is independently H, D, F, Cl, Br, I, C1-C6 alkyl or C1-C6 alkoxy;
• R20 is H, D, F or C1-C12 alkyl;
• p is an integer from 0 to 20, inclusive;
• and
• *** indicates the point of attachment of E to G and ** indicates the point of attachment of G to E.