Starting from the antibiotic A-40926 and the aglycone of A-40926 a series of compounds were prepared by modifying the free functionalities. Their antimicrobial activity was determined, particularly against Neisseria gonorrhoeae, against which A-40926, unlike other natural glycopeptides, is active. Improved in vivo activity was displayed by the monomethyl ester of A-40926 esterified at the carboxyl group of the N-acylamino-glucuronyl moiety.

40 : 40 : 20, respectively. Factor T was purified by eluting with acetonitrile water 60 : 40. The purified antibiotics precipitated from the elutes after elimination of the acetonitrile under vacuum.GE2270factors were obtained as white powders showing HPLCretention times and molecular weights reported in Table 1. Factor T showed UV spectra with ^MCl 250, 280 (sh), 345 (sh); ^maxN KOH 240 (sh), 290 (sh), 345 (sh); /l^sphate buffer pH 7'38 250 (sh), 310 (sh), 345 (sh); A|£á" 240 (sh), 275 (sh), 290 (sh), 311, 335 (sh). The other factors showed identical