Pharmaceutical and diagnostic compositions for use in the treatment and diagnosis of neurodegenerative diseases or amyloid diseases

Pharmaceutical or diagnostic composition comprising active substance of formula VI-2

• wherein R1 and R3 are selected from
• (i) H, OH, NH2 or a halogen atom;
• (ii) single- or multi-branched or straight-chain alkyl or heteroalkyl groups with one or two rings and up to 10 carbon atoms;
• (iii) cyclic alkyl or heteroalkyl groups with 1 or 2 rings or aryl or heteroaryl groups with up to 10 carbon atoms each;
• and
• wherein R2 is selected from
• (i) OH, NH2 or a halogen atom;
• (ii) single- or multi-branched or straight-chain alkyl or heteroalkyl groups with one or two rings and up to 10 carbon atoms;
• (iii) cyclic alkyl or heteroalkyl groups with 1 or 2 rings or aryl or heteroaryl groups with up to 10 carbon atoms each;
• and
• wherein for the structure of Formula VI-2, the alkyl, heteroalkyl, aryl or heteroaryl groups comprise 0, 1, 2, 3 or 4 substituents, each selected from a group consisting of Cl, Fl, Br and I, X1 is selected from the group consisting of H, F, I, Br, Cl, OH, OA, SH, SA, NH2, NHA1, NA1A2, and A;
• wherein A, A1, and A2 are independently a branched, straight-chain or cyclic alkyl group with 1, 2, 3, 4, 5, or 6 carbon atoms, an aromatic group with 1, 2, 3, 4, 5, 6, or 7 carbon atoms or combinations thereof, wherein individual carbon atoms are optionally replaced with 1, 2, 3, or 4 S, N, or O atoms, and X2 is O or S.