Synthesis and evaluation of stilbenylbenzoxazole and stilbenylbenzothiazole derivatives for detecting β-amyloid fibrils

This paper describes a novel series of stilbenylbenzoxazole (SBO) and stilbenylbenzothiazole (SBT) derivatives for β-amyloid specific binding probes. These 24 compounds were synthesized and evaluated by competitive binding assay against β-amyloid 1–42 (Aβ42) aggregates using [125I]TZDM. All the derivatives displayed higher binding affinities with Ki value in the subnanomolar range (0.10–0.74 nM) than Pittsburgh Compound-B (PIB) (0.77 nM). Among these derivatives, SBT-2, 5-fluoroethoxy-2-{4-[2-(4-methylaminophenyl)vinyl]phenyl}benzothiazole, showed lowest Ki value (0.10 nM). In conclusion, the preliminary results suggest that these compounds are implying a possibility as a probe for detection of Aβ fibrils in Alzheimer’s disease (AD) patients.