18f-saccharide-folates

Compounds of formula I,

• wherein
• Z is a pteroate or derivative thereof,
• Y1,Y2 are independently of each other O, N or S,
• m is 1, 2 or 3, and
• Q1, Q2 are independently of each other H, a protecting group or a group of formula
• -L-A-L′-18F,
• wherein
• L,L′ are independently of each other a linking group, such as a covalent bond or a straight-chain or branched C(1-8)alkyl, which is unsubstituted or substituted by at least one CN, Hal, OH, NH2, CO2H, NO2, and wherein one or more of the non-adjacent CH2 groups may independently be replaced by a group selected from —O—, —CO—, —CO—O—, —O—CO—, —NR′—, —NR′—CO—, —CO—NR′—, —NR′—CO—O—, —O—CO—NR′—, —NR′—CO—NR′—, —CH═CH—, —C—, —O—CO—O—, —S—R′—, —SO3R′—, or a five- or six-membered heterocycle, wherein R′ represents H or C(1-8)alkyl, and
• A is a saccharide group,
• with the proviso that at least one of Q1 and Q2 is a group of formula -L-A-L′-18F.