Hydrochloric Acid → 1,4,7,10-Tetraazacyclododecane-1,7-diacetic acid

Reaction equation

[O:1]=[C:2]1[N:13]2[CH2:14][CH2:15][N:4]([CH2:5][CH2:6][NH:7][CH2:8][CH2:9][N:10]([CH2:16][C:17]([OH:19])=[O:18])[CH2:11][CH2:12]2)[CH2:3]1.Cl.[OH-:21].[Na+]>>[N:10]1([CH2:16][C:17]([OH:19])=[O:18])[CH2:11][CH2:12][NH:13][CH2:14][CH2:15][N:4]([CH2:3][C:2]([OH:21])=[O:1])[CH2:5][CH2:6][NH:7][CH2:8][CH2:9]1

Participants

Reactant 3

HCID 313Hydrochloric Acid

HCID 14798Sodium Hydroxide

HCID 22117785HCID 22117785, compound

Product 1

HCID 3873531,4,7,10-Tetraazacyclododecane-1,7-diacetic acidYield 86.5%

Procedure

20 g (0.074 mol) of 12-oxo-1,4,7,10-tetraazabicyclo[8.2.2]tetradecane-4-acetic acid, prepared as described in example 5, are dissolved in 88.8 g of 10% NaOH. The solution is refluxed overnight, then cooled and acidified to pH 12 by addition of conc. HCl. The resulting solution is percolated on a column containing 600 ml of anionic exchanger resin IRA420 (Rohm & Haas), which is washed repeatedly with water, then eluted with 1N HCl. The fractions containing the product are combined and concentrated at reduced pressure to a volume of about 500 mL. The solution is percolated on a column containing 2 L of polyvinylpyridine resin (PVP), eluting with water, the fractions containing the desalted product are collected, combined and concentrated to dryness under vacuum. The crude solid is recrystallized from methanol/acetone=8/2, finally dried in a static drier at 50° C. under vacuum. 18.5 g (0.064 mol) of 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid are obtained.