Synthesis and Preliminary Biological Evaluation of Fluorescent Glycofused Tricyclic Derivatives of Amyloid β‐Peptide Ligands

Fluorescent glycofused tricyclic compounds were synthesized through the domino conjugate oxa‐Michael addition/aldol condensation of 2‐hydroxybenzaldehydes with protected 3‐oxoglucal by exploiting activation with an organocatalyst. Stereoselectivity was obtained by using ( R )‐(+)‐α,α‐diphenyl‐2‐pyrrolidinemethanol trimethylsilyl ether as the catalyst. All synthesized compounds presented good optical properties. All compounds were able to bind to synthetic amyloid β 1–42 peptide aggregates and to label amyloid plaques from brain sections of transgenic mice affected with Alzheimer's disease with staining properties comparable to thioflavin T.