Amides of malonic acid derivatives and protected dipeptides containing amino malonic acid have been synthesized and converted into the corresponding monothio analoga and endothiodipeptides. By reduction of the thioamides terminal protected β-carboxy amino derivatives were obtained. Reduction of endothiodipeptides containing amino malonic acid as the carboxy component resulted in protected ψ [CH2NH] pseudodipeptides for the use ...