The present invention relates to the new 3-decladinosyl derivatives of 9a-N-carbamoyl­and 9a-N-thiocarbamoyl-9-deoxo-9-dihydro-9a-aza-9a-homoerythromycin A of the general formula (I), their pharmaceutically acceptable addition salts with inorganic or organic acids and their hydrates, Wherein R1 individually stands for hydrogen or together with R2 stands for double bond, R2 individually stands for hydrogen, hydroxyl or a group of the formula (II), wherein Y individually stands for monocyclic aromatic ring, unsubstituted or substituted with groups which are selected independently from halogen, OH, OMe, NO2, NH2 or R2 together with R3 stands for ketone or together with R1 stands for double bond, R3 individually stands for hydrogen or together with R2 stands for ketone or together with R4 stands for ether, R4 individually stands for hydroxyl, a OCH3 group or together with R3 stands for ether, R5 individually stands for C1-C4 alkyl group, C2-C4 alkenyl group, -(CH2)m Ar, wherein Ar individually stands for phenyl or phenyl substituted with one or two groups which are selected independently from halogen or halogen alkyl, and m is 0-3, R6 individually stands for hydrogen or hydroxyl protected group, X stands for oxygen or sulphur, to intermediates for synthesis of other macrolide compounds with antibacterial activity, to the process for their preparation, to their pharmaceutically acceptable addition salts with inorganic or organic acids and their hydrates, to the process for the preparation of pharmaceutical compositions, as well as the use of pharmaceutical compositions for treating bacterial infections.