O.[NH:2]([CH2:7][C:8]([O-:10])=[O:9])[CH2:3][C:4]([O-:6])=[O:5].[Na+].[Na+].Cl[C:14]([O:16][CH2:17][C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1)=[O:15].[OH-].[Na+]>O>[CH2:17]([O:16][C:14]([N:2]([CH2:7][C:8]([OH:10])=[O:9])[CH2:3][C:4]([OH:6])=[O:5])=[O:15])[C:18]1[CH:23]=[CH:22][CH:21]=[CH:20][CH:19]=1Disodium iminodiacetate monohydrate (11.7 g, 0.060 m) was dissolved in water (40 ml) and cooled to 0°. Benzyl chloroformate (13.3 g, 0.078 m) was added in portions as the pH of the solution was kept at 9-12 by addition of 2N sodium hydroxide solution as needed. When addition was complete the mixture was stirred an additional 3 hours at 0°-10° C., then extracted with diethyl ether. The aqueous layer was acidified with concentrated hydrochloric acid and extracted with ethyl acetate. The organic layer was separated, dried over sodium sulfate and concentrated to give 13.0 g (81%) of N-benzyloxycarbonyliminodiacetic acid (V-C).
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