DERIVATIVE OF JOSAMYCIN OR JASAMYCIN S AND ITS PREPARATION

摘要

NEW MATERIAL:Title compounds of the formula [one of Rs is H and the other lower alkyloxy or thio, aryloxy or thio; the dotted line means a single or conjugated double bond]. EXAMPLE:9-O-Methyljosamycin dimethylacetal and 13-O-methyljosamycin S-dimethylacetal mixture. USE:Antibacterial agent. They have no bitter taste characterized by josamycin. PREPARATION:The reaction of josamycin or josamycin S with an alcohol or thiol in an anhydrous solvent, e.g., acetone or benzene, is effected preferably in the presence of an acidic substance in an amount of 1.1-2.2 times the molar quantity of the starting substance. The reaction mixture or the acetal is catalytically reduced to form the tetrahydroacetal, which is deacetalized using an aqueous mineral acid to give the objective compound.