Strecker-Derived Methodology for Library Synthesis of N-Acylated α-Aminonitriles

Abstract

The Strecker reaction is a three-component condensation of an aldehyde, an amine, and hydrogen cyanide, delivering an α-amino carbonitrile. Despite extensive investigations, the possibility to use amides instead of amines as one of the three condensation partners has been largely neglected. Nonetheless, the N-acylated α-aminocarbonitriles that are obtained in this way are of direct interest for drug discovery, because they make up a well-known class of mechanism-based inhibitors of serine- and cysteine-type hydrolases. In response, we have thoroughly explored the corresponding variant of the Strecker reaction, focusing on catalyst use, solvent, reaction time, and cyanide source. Optimized parameters were combined in a sequential one-pot protocol for which the scope was found to be compatible with library synthesis applications. Product yields ranged from 7 to 90%, and conditions were found to be mild and tolerant to a wide range of functional groups, including moieties that are typically present in druglike molecules.