Ugi reactions with ammonia offer rapid access to a wide range of 5-aminothiazole and oxazole derivatives.

A series of Ugi reactions has been successfully performed using ammonia as the amine component, employing 2,2,2-trifluoroethanol as a non-nucleophilic solvent in order to suppress known side reactions. Utilizing concentrated aqueous ammonia as a convenient source, this approach offered a simple, one-step assembly of Ugi adducts suitable for elaboration into a variety of 5-aminoazole compounds through postcondensation modifications. Free or N-substituted 5-aminothiazoles and 5-(trifluoroacetamido)oxazoles were all prepared by this improved methodology. The scope of the synthetic route developed and application of the different products are discussed.