Deaminoteicoplanin and its derivatives. Synthesis, antibacterial activity, and binding strength to Ac-D-Ala-D-Ala

Teicoplanin and its acid hydrolysis products were deaminated with hydroxylamine-O-sulfonic acid (HOS). A few amides of these deaminoteicoplanins were also prepared. The loss of the terminal amino group reduces in vitro activity against staphylococcal and streptococcal bacteria to one-half to one-third, while binding strength to Ac-D-Ala-D-Ala, measured by differential UV spectroscopy, is reduced to one-tenth that of teicoplanin. The in vitro activity is further reduced by the presence of serum, and this is attributable to the increased lipophilicity and total negative charge of the deamino compounds. Comparison of UV spectra of deaminoteicoplanins with those of parent compounds made it possible to single out the most acid phenol group of teicoplanin aglycon (OH-4; pK = 8.2).