A compound selected from the group consisting of a compound of the formula ##STR1## wherein R and R.sub.1 are --OH or --O-acyl of an organic carboxylic acid of 2 to 20 carbon atoms, R.sub.2 is hydrogen or methyl, R.sub.3 is --(CH.sub.2).sub.m --R.sub.4 or ##STR2## or --N--(CH.sub.2).sub.q --R.sub.4, m is an integer from 1 to 6, n, p and q are individually an integer from 0 to 6, A and B are individually selected from the group consisting of hydrogen, halogen and alkyl of 1 to 8 carbon atoms with the geometry of the double bond being E or Z or a mixture of E and Z or A and B form a triple bond, R.sub.4 is an optionally substituted mono- or polycyclic heterocycle and their non-toxic, pharmaceutically acceptable acid addition salts having antibiotic properties.