The present invention relates to new substituted nitrogen-containing heterobicyclic compounds of general formula ##STR00001## wherein B, X.sup.1 to X.sup.3 and R.sup.1 to R.sup.5 are defined as in claim 1, the tautomers, the enantiomers, the diastereomers, the mixtures thereof and the salts thereof, particularly the physiologically acceptable salts thereof with inorganic or organic acids or bases, which have valuable properties.The compounds of the above general formula I as well as the tautomers, the enantiomers, the diastereomers, the mixtures thereof and the salts thereof, particularly the physiologically acceptable salts thereof with inorganic or organic acids or bases, and their stereoisomers have valuable pharmacological properties, particularly an antithrombotic activity and a factor Xa-inhibiting activity.