摘要 |
The invention relates to the compounds of the formula I <CHEM> wherein the C(=NOH)-NH2 group may be in tautomeric form; and pharmaceutically acceptable salts thereof, in which: R1 is amino or amino which is mono- or disubstituted X1 and X3, independently of one another, are oxygen (-O-) or sulphur (-S-); and X2 is a divalent aliphatic hydrocarbon radical which may be interrupted by an aromatic radical; The compounds are useful, for example, as selective LTB4 receptor antagonists in the treatment of conditions or syndromes in mammals which are responsive to LTB4 receptor antagonism. They are prepared in a manner known per se. |