An Umpolung route to peptide mimetics of thyrotropin-releasing hormone based on a cyclohexane framework

Peptide mimetics of thyrotropin-releasing hormone (TRH) in which the peptide backbone is replaced by cyclohexane were synthesized from the cyclohexenone precursor 7. The aromatic side chains of the mimetics were derived from the corresponding aldehydes which were attached to the cyclohexenone via the Wittig reagent 8. The TRH mimetics are active in a mouse model of cognitive performance.