Indolyl-3-glyoxylic acid derivatives having therapeutically valuable properties

A method of inhibiting multidrug-resistant tumor growth or inhibiting metastasis, in a patient comprising administering to said patient an amount of one or more N-substituted indol-3-glyoxylamides of formula I or a physiologically tolerable acid addition salt thereof effective for inhibiting multidrug-resistant tumor growth or inhibiting metastasis

• wherein the radicals R, R1, R2, R3, R4, and Z have the following meanings:
• R is hydrogen;
• R1 is a pyridine structure of formula II
• where the pyridine structure is bonded at either the 2, 3, or 4 position of the ring and is optionally substituted by substituents R5 or R6 or both R5 and R6, wherein R5 and R6 can be identical or different and are independently selected from (C1-C6)-alkyl, (C3-C7)-cycloalkyl, (C1-C6)-alkoxy, nitro, amino, hydroxyl, halogen, trifluoromethyl, ethoxycarbonylamino radical and a carboxyalkyloxy group in which the alkyl group has 1-4 C atoms;
• R2 is a (C1-C6)-alkyl group, where the alkyl group is monosubstituted by phenyl, which is optionally substituted by one or more substituents selected from halogen, (C1-C6)-alkyl, (C3-C7)-cycloalkyl, a carboxyl group, a carboxyl group esterified with a C1-C6-alkanol, a trifluoromethyl group, a hydroxyl group, a methoxy group, an ethoxy group a benzyloxy group, a 2-quinolyl group or a 2-, 3- or 4-pyridyl group, wherein the 2-quinolyl and 2-, 3-, or 4-pyridyl groups can both in each case be mono- or polysubstituted by halogen, (C1-C4)-alkyl group or (C1-C4)-alkoxy;
• R3 and R4 can be identical or different and are independently selected from hydrogen, (C1-C6)-alkyl, (C3-C7)-cycloalkyl, (C1-C6)-alkanoyl, (C1-C6)-alkoxy, halogen, benzyloxy, a nitro group, an amino group, a (C1-C4)-mono or dialkyl-substituted amino group, a (C1-C6) alkoxycarbonylamino group, and a (C1-C6)-alkoxycarbonylamino-(C1-C6)-alkyl group;
• and
• Z is O or S.