Abstract (S)-3-(Dimethylamino) methylidene-5-benzyltetramic acid derivatives 4a and 4b were prepared in three steps from N-protected (S)-3-phenylalanines 1a and 1b, respectively. Similarly, N-[N-(benzyloxycarbonyl) glycyl] glycine (1c) was transformed into the enaminone 4c. Acid-catalysed coupling of enaminones 4a-c with aliphatic, aromatic, and heteroaromatic primary amines 5-34 afforded the corresponding N (3′)-substituted 3- ...