Pyridine → (2,6-dioxomorpholinoethyl)-N6-(ethoxycarbonylmethyl)-3,6-diazaoctanedioic acid

Participants

Reaction Steps

A suspension of 21.2 g (50 mmol) of N3,N6 -bis-(carboxymethyl)-N9 -(ethoxycarbonylmethyl)-3,6,9-triazaundecanedioic acid (J. Pharm. Sci. 68, 1979, 194) in 250 ml of acetic anhydride is stirred, after the addition of 42.2 ml of pyridine, for three days at room temperature. Then the precipitate is suctioned off, it is washed three times, each time with 50 ml of acetic anhydride and then stirred up for several hours with absolute diethylether. After suctioning off, washing with absolute diethylether and drying in a vacuum at 40° C., 18.0 g (89% of theory) of a white powder with a melting point of 195°-196° C. is obtained.

Provenance & Evidence