Substituted 1,2-Thiazetidine 1,1-Dioxides. Synthesis of (RS)-and (S)-1,2-Thiazetidine-3-acetic Acid 1,1-Dioxide and Its Reactions with Amino Acids and Dipeptides. -The synthesis of β-sultam peptides by condensation of (RS)-and (S)-1,2-thiazetidine-3-acetic acid 1,1-dioxide (II), with various L-amino acid esters or dipeptide esters is presented. -(ROEHRICH, T.; THAHER, B. A.; MANICONE, N.; OTTO*, H.-H.; Monatsh. Chem. 135 (2004) 8, 979-999; Inst. Pharm./Med. Chem.,