Aniline → N3,N6-Bis(carboxymethyl)-N9-phenylcarbamoylmethyl-3,6,9-triazaundecanedioic Acid

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Reaction Steps

In a 1-liter autoclave, 42.1 g (0.1 mol) of N3,N6 -bis(carboxymethyl)-N9 -ethoxycarbonylmethyl-3,6,9-triazaundecanedioic acid is heated with 93.1 g (1 mol) of aniline for 30 hours to 110° C. After cooling, the content is dissolved in 800 ml of methanol and the solution concentrated to dryness under vacuum. The residue is combined with 800 ml of water and the excess aniline exhaustively extracted with methylene chloride. The aqueous phase is passed, after an initial distillation, over 100 ml of "Amberlite" IR 120. The acidic eluate is concentrated and the residue dried under vacuum at 50° C., thus obtaining 35.1 g (75% of theory) in the form of a white powder with a melting point of 125° C.

Provenance & Evidence