Dimethylformamide → N-Methoxyacetyl-5-methylamino-2,4,6-triiodoisophthalic acid-N,N-bis-(ethoxycarbonylmethyl)-amide-chloride

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Reaction Steps

A solution of 68.2 g (100 mmol) of N-methoxyacetyl-5-methylamino-2,4,6-triiodoisophthalic acid dichloride (EP 0015867) in 500 ml of N,N-dimethylformamide is mixed with 22.6 g (100 mmol) of iminodiacetic acid diethyl ester hydrochloride (production according to Jongkees, Recl. Trav. Chimys-Bas, 27, 296 (1908)) and 10.1 g (100 mmol) of triethylamine. A suspension results, which is stirred overnight under argon at room temperature. Then, it is concentrated by evaporation and the residue is chromatographed on silica gel 60 (Merck) with dichloromethane/ethyl acetate. After concentration by evaporation of the product fractions, a colorless solid is obtained, which is dried in a vacuum.

Provenance & Evidence