Epothilone derivatives, process for their production, and their pharmaceutical use

An epothilone compound of formula I,

• in which
• R4 means hydrogen, C1-C10 alkyl, aryl, C7-C20 aralkyl,
• R5 means hydrogen, C1-C10 alkyl, aryl, C7-C20 aralkyl,
• wherein, for R4 and R5, aryl is phenyl, wherein said phenyl is optionally substituted in one or more places by halogen, OH, O-alkyl, CO2H, CO2-alkyl, —NH2, —NO2, —N3, —CN, C1-C20 alkyl, C1-C20 acyl and/or C1-C20 acyloxy groups, and
• wherein, for R4 and R5, aralkyl is benzyl or phenylethyl, wherein said benzyl or phenylethyl is optionally substituted in one or more places by halogen, OH, O-alkyl, CO2H, CO2-alkyl, —NO2, —N3, —CN, C1-C20 alkyl, C1-C20 acyl and/or C1-C20 acyloxy groups,
• R6, R7 each mean a hydrogen atom, or together mean an additional bond to result in a double bond on the ring between their two positions or together mean an oxygen atom to provide an epoxide ring,
• R8 means a methyl group or hydrogen,
• and at the same time, R1a and R1b together stand for a trimethylene group, R2 stands for a phenyl or benzyl radical, and X stands for a 2-pyridyl, or
• at the same time R1a and R1b together stand for a trimethylene group, R2 stands for a methyl, ethyl or propyl group and X stands for a 2-pyridyl, or
• at the same time R1a and R1b in each case stand for a methyl group, R2 stands for a methyl, ethyl or propyl radical, and X stands for a 2-pyridyl,
• wherein the nitrogen atom and/or the sulfur atom in X can be present in oxidized form, and
• wherein, if R2 and R8 in each case mean a methyl radical, X can be only one 2-pyridyl radical that is optionally oxidized on the nitrogen atom,
• or a stereoisomer thereof.