The invention relates to novel and valuable intermediate compounds of the general formula (VIII) which can be used for the preparation of novel compounds comprising an antibacterial action, especially with a strong antibacterial action against helicobacter pylori, and pharmaceutically acceptable salts thereof. In the general formula (VIII) X is hydrogen or halogen, Y is hydrogen or a substituted or unsubstituted aralkyloxycarbonyl group having 8-19 carbon atoms, Z is hydrogen, a substituted aralkyloxycarbonyl group having 8-19 carbon atoms or a substituted alkoxycarbonyyl group having 2-19 carbon atoms, except that X, Y and Z are all hydrogen.