Synthesis and biological activity of spergualin analogues. I

Stable spergualin analogues were synthesized by substitutions of the alpha-hydroxyglycine residue of spergualin with various alpha- or omega-amino acids. The antitumor activity of these analogues against L1210 and their immunosuppressive effects on delayed-type hypersensitivity and antibody formation was then examined. Analogues substituted with glycine and L-serine showed significant biological activity but were less potent than 15-deoxyspergualin. Among the analogues synthesized so far, 10-[N-4-(4-guanidinophenyl)butyryl-L-seryl]-1,5,10-triazadecane has possessed the strongest antitumor and immunosuppressive activities.