Use of novel pan-cdk inhibitors for treating tumors

A method for the treatment of a tumor disorder comprising administering to a human in need thereof a compound of the general formula (I)

• in which
• X represents —O— or —NH—, and
• R1 represents a methyl, ethyl, propyl or isopropyl group, and
• R2 and R3 independently of one another represent hydrogen, a methyl or ethyl group, and
• R4 represents a C1-C6-alkyl group or a C3-C7-cycloalkyl ring,
• or a physiologically acceptable salt, diastereomer or enantiomer thereof.