Abstract
Treatment of erythromycin B (2) with tetraacetylglucosyl bromide in nitromethane and pyridine afforded the 8, 9-anhydro-69-hemiketal of erythromycin B (4) in yields above 80%. Hydroxylation of compound 4 with m-chloroperbenzoic acid, irrespective of the solvent used, yielded the N-oxide of 8-hydroxyerythromycin B 6911-spiroketal (6). After reduction of the N-oxide function of compound 6 and subsequent hydrolysis with aqueous acetic acid, 8-hydroxyerythromycin B was obtained. The antibacterial activity of this antibiotic against Bacillus pumilus (in vitro) was a half that exhibited by erythromycin B.
