The stereoisomeric N, Nf-dimethanesu1fonyl-2, 2'-biaziridines (S), the related symmetrical position isomers of dimethanesulfonamidobutanediol bismethanesulfonates (5, lo), and dihalogenodimethanesulfonamidobutanes (4, 9) were prepared. Except for 4 the synthesis could be performed by two independent routes establishing the optical purity of the compounds. The results of an attempted preparation of 2, 3-diamino-1, 4-dibromo-butane ...