Ugi Reactions with Ammonia Offer Rapid Access to a Wide Range of 5-Aminothiazole and Oxazole Derivatives
摘要:
A series of Ugi reactions has been successfully performed using ammonia as the amine component, employing 2,2,2-trifluoroethanol its a non-nucleophilic solvent in order to suppress known side reactions. Utilizing concentrated aqueous ammonia its it convenient Source, this approach offered a simple, one-step assembly of Ugi adducts suitable for elaboration into it 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.