Structural relationships of new 2,4-diamino-5-benzylpyrimidines

By introducing a double ether group, e.g. an alkoxyalkoxy-group in the aromatic structure of the 2,4-diamino-5-benzylpyrimidines the water- and lipid-solubility was clearly altered with respect to trimethoprim. A compound with enhanced activity, tetroxoprim, was further studied. Substituting oxygen in position 4 by a sulphur atom leads to interesting compounds with antibacterial activity.