Novel compounds for the diagnosis, treatment and prevention of diseases associated with the aggregation of alpha-synuclein

A compound represented by the general formula Ia, Ib, IIa or IIb

• or a prodrug, solvate or salt thereof,
• wherein
• X1, X2, and X3 are independently selected from CR2, N and NR1, with the proviso that at least two of X1, X2, and X3 are N or NR1;
• Y1, Y2, Y3, Y4, Y5, Y6, Y7 and Y8 are independently selected from CR3 and N, with the proviso that at least one of Y1, Y2, Y3, Y4, Y5, Y6, Y7 and Y8 is N;
• R1 is independently selected from hydrogen, C1-4 alkyl and —(CH2)—O—P(═O)(OR)(OR), wherein C1-4 alkyl can be optionally substituted by one or more halogen;
• R2 is independently selected from hydrogen, halogen, and C1-4 alkyl, wherein C1-4 alkyl can be optionally substituted by one or more halogen;
• R is hydrogen or a cation;
• R3 is hydrogen, halogen, C1-4 alkyl, OH and C1-4 alkoxy, wherein C1-4 alkyl and C1-4 alkoxy can be optionally substituted by one or more halogen;
• R4 and R5 are independently selected from H and C1-4 alkyl, wherein C1-4 alkyl can be optionally substituted by one or more halogen or wherein R4 and R5 together with the nitrogen atom to which they are bound form a 4- to 6-membered saturated, heterocyclic ring which optionally contains one or more heteroatoms selected from O and N in addition to the nitrogen atom to which R4 and R5 are bound, wherein the 4- to 6-membered saturated, heterocyclic ring can be optionally substituted by one or more R6;
• R6 is independently selected from halogen, C1-4 alkyl, OH and C1-4 alkoxy, wherein C1-4 alkyl and C1-4 alkoxy can be optionally substituted by one or more halogen;
• and
• Hal is halogen.