Novel erythromycin a derivatives

Abstract

Novel erythromycin derivatives in the syn form or anti form or mixtures of the syn and anti forms of the formula ##STR1## wherein A is a linear or branched alkylene of 1 to 6 carbon atoms, R is selected from the group consisting of optionally substituted alkoxy of 1 to 6 carbon atoms, optionally substituted alkenyloxy and alkynyloxy of 2 to 6 carbon atoms, optionally substituted alkylthio of 1 to 6 carbon atoms, optionally substituted alkenylthio and alkynylthio of 2 to 6 carbon atoms with the thio group optionally oxidized to the sulfoxide or sulfone form, optionally substituted aryloxy and arylthio, optionally substituted aralkyloxy and arylalkylthio, the thio derivatives optionally oxidized to sulfoxide or sulfone, ##STR2## optionally substituted quaternary ammonium group, halogen, optionally substituted 1,2-epoxyethyl and the group resulting from opening of the epoxy with a nucleophilic reactant, ##STR3## a free or protected formyl, --COOR', thiocyanate, --CN, acyl and carbamoyl, R.sub.1 and R.sub.2 are individually selected from the group consisting of hydrogen, and optionally substituted alkyl of 1 to 6 carbon atoms or taken together with the nitrogen atom to which they are attached form an optionally substituted, optionally unsaturated heterocycle which can contain another heteroatom, B is selected from the group consisting of optionally substituted alkyl and alkoxy of 1 to 6 carbon atoms, optionally substituted aryl and aryloxy and optionally substituted aralkyl and aralkoxy of 1 to 6 alkyl carbon atoms, R' is selected from the group consisting of hydrogen, a cation and an ester group, R.sub.a is selected from the group consisting of hydrogen and acyl of an organic carboxylic acid of 1 to 18 carbon atoms and their non-toxic, pharmaceutically acceptable acid addition salts having very good antibiotic activity and their preparation.