Acetic Anhydride → 2,2'-[[2-[(3-Iodo-4-methylphenyl)amino]-2-oxoethyl]-imino]bisacetic acid

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Reaction Conditions

Reaction Steps

A slurry of 4.78 g of nitrilotriacetic acid in 40 ml of dry pyridine (dried over molecular sieves) is heated to 60° C. Acetic anhydride (2.55 g) is added slowly and the solution is heated to 100° C. After heating for 0.5 hour, the solution is cooled to 40° C. and a solution of 5.8 g of 3-iodo-4-methylaniline in 20 ml of dry pyridine is added over 25 minutes. The solution is heated at 100° C. for 1.0 hour. The reaction is cooled and rotary evaporated to a residue which is dissolved in 65 ml of 10% sodium hydroxide. This solution is extracted twice with 50 ml portions of methylene chloride diluted with 100 ml of distilled water, and neutralized with concentrated HCl to pH 3.2. The crude product is refrigerated for about 16 hours, filtered, washed twice with 50 ml portions of distilled water, and dried under vacuum at 40° C. The crude product (8.0 g) is recrystallized after Darco treatment to yield 5.7 g of product, melting point 213.5°-215.0° C. (dec).

Provenance & Evidence