Library synthesis and screening: 2,4-diphenylthiazoles and 2,4-diphenyloxazoles as potential novel prion disease therapeutics.

Transmissible spongiform encephalopathies (TSEs) are a family of invariably fatal neurodegenerative disorders for which no effective therapeutics are currently available. In this paper, we report on the synthesis and screening of a small library of 2,4-diphenylthiazol-5-ylamine and 2,4-diphenyloxazol-5-ylamine derivatives as potential novel prion disease therapeutics. Various synthetic strategies were investigated, including a novel phosgene-mediated cyclization of 2-N-benzoylphenylglycinonitrile, and a total of 45 compounds were synthesized. Library members were tested for both binding to prion protein (PrPC) using the surface plasmon resonance technique and for inhibition of PrPSc formation in persistently infected SMB cells. Of the compounds prepared, 15 were found to bind to human PrPC and six showed inhibition of PrPSc formation, displaying EC50s between 1.5 and 20 μM.