TRI-IODATED ISOPHTHALIC ACID DIAMIDES AS NON-IONIC X-RAY CONTRAST AGENTS

The invention provides compounds of the general formula (I) in which The amide radicals -CO-NR1R2 and -CO-NR3R4 are different from one another, and R1 represents a hydrogen atom or a lower alkyl radical, R2 represents a mono- or poly-hydroxyalkyl radical, R3 represents a hydrogen atom or a lower alkyl radical, R4 represents a mono- or poly-hydroxyalkyl radical, R5 represents a lower alkyl radical or a lower alkyl radical substituted by 1 or more of the same or different substituents selected from hydroxy groups and lower alkoxy radicals, R6 represents a hydrogen atom, a lower alkyl radical or a mono- or poly-hydroxy-lower alkyl radical, useful as X-ray contrast agents, especially for intravascular, subarachnoidal and local application.