Synthesis of derivatives of (9S)-12-methylene erythromycin and their antibacterial activity in vitro

AimTo synthesizs of derivatives of (9S)-12-methylene erythromycin possessed potent antibacterial activity.MethodsUsing erythromycin A as a starting material,via two intermediate compounds protected 12,21-dehydroerythromycin A and 6,7∶12,21-didehydro erythromycin A, several 9-O,11-O-ethylidene compounds were obtained.During this process, benzyl and isopropyl have been selected as the protecting group.The structures of compounds obtained were confirmed with ¹³C NMR and MS-FAB.Their antibacterial activity in vitro was tested.ResultsEleven derivatives of erythromycin were synthesized.Five of them were unknown compounds.ConclusionThe preliminary biological test showed that two target compounds exhibited less potent antibacterial activity in vitro.