Synthesis and antibacterial activity of novel 4″-O-arylalkylcarbamoyl and 4″-O-((arylalkylamino)-4-oxo-butyl)carbamoyl clarithromycin derivatives

Synthesis and antibacterial activity of novel 3-O-descladinosylazithromycin derivatives

Novel series of novel 3-O-arylalkylcarbamoyl descladinosylazithromycin derivatives with the 2'-O-acetyl and 11,12-cyclic carbonate groups, the 11,12-cyclic carbonate group and the 11-O-arylalkylcarbamoyl side chain, and 2'-O-arylalkylcarbamoyl descladinosylazithromycin with the 11,12-cyclic carbonate group were designed, synthesized and evaluated for their antibacterial activity using broth microdilution method. The results showed that the majority of the target compounds showed moderate to favorable activity against six kinds of susceptible strains and almost all of them displayed significantly improved activity compared with references against three erythromycin-resistant strains of S. pneumoniae B1 expressing the ermB gene, S. pneumoniae AB11 expressing the ermB and mefA genes, and S. pyogenes R1. In particular, compound 6h exhibited the most potent activity against susceptible B. subtilis ATCC9372 (0.5 μg/mL), penicillin-resistant S. epidermidis (0.125 μg/mL), and erythromycin-resistant S. pneumoniae B1 (1 μg/mL) and S. pneumoniae AB11 (1 μg/mL), which were 2-, 2-, 256-, 256-fold better activity than azithromycin, respectively. Additionally, compounds 6f (0.5 μg/mL) and 6g (0.25 μg/mL) were the most active against S. pneumoniae A22072, which were 8- and 16-fold better activity than azithromycin (4 μg/mL). As for erythromycin-resistant S. pyogenes R1, compound 5a presented the most excellent activity (8 μg/mL), showing 32- and 32-fold higher activity than azithromycin (256 μg/mL) and clarithromycin (256 μg/mL).

Synthesis of 4″-O-desosaminyl clarithromycin derivatives and their anti-bacterial activities

A series of new 4″-O-desosaminyl clarithromycin derivatives were designed and synthesized. The efficient synthesis routes of 6-deoxy-desosamine donors 8 and 11 were developed and the methodology of glycosylation of clarithromycin 4″-OH with desosamine was studied. The activities of the target compounds were tested against a series of macrolide-sensitive and macrolide-resistant pathogens. Some of them showed activities against macrolide sensitive pathogens, and compounds 19 and 22 displayed significant improvement of activities against sensitive pathogens and two strains of MRSE, which verified the importance of desosamine in the interaction of macrolide and its receptor, and offered valuable information of the SAR of macrolide 4″-OH derivatives.

Novel C-4'' modified azithromycin analogs with remarkably enhanced activity against erythromycin-resistant Streptococcus pneumoniae: the synthesis and antimicrobial evaluation

Three novel structural series of C-4'' modified azithromycin analogs with two amide groups, which were connected by different alkyl linkage, were designed, prepared and evaluated for their in vitro antibacterial activity against seven phenotypes of respiratory pathogens. Among them, 7d, 8j and 9j, as representatives of corresponding series, exhibited remarkably improved activity against erythromycin-resistant Streptococcus pneumoniae expressing the erm gene, the mef gene, and the erm and mef genes. In addition, 7a-c, 7f-h, 7j, 8d, 8g, 8i, 9a-b and 9i displayed favorable efficacy against erythromycin-resistant S. pneumoniae A22072 expressing the mef gene.