1,1,3,3-Tetramethylguanidine → But-2-enedioic acid bis-[2-(2-dimethylamino-ethoxy)-ethyl]ester

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Reaction Steps

The solution of 2-[2-(dimethylamino)-ethoxy]ethanol (6.65 g, 50 mmol, 2.5 equiv.) and 4-dimethylaminopyridine (11 mg) in toluene (20 ml) is cooled to −20° C. Separate solutions of fumaryl chloride (2.3 ml, 20 mmol, 1.0 equiv.) and 1,1,3,3-tetramethylguanidine (5.0 ml, 40 mmol, 2.0 equiv.) in toluene (each 25 ml) are added dropwise simultaneously via syringe pump over 80 min. A dark suspension is formed. After complete addition, the cooling bath is removed and stirring continued at 23° C. for 40 min. Active charcoal (1.0 g) is added and the mixture is filtered over a short pad of basic Al2O3, which is further rinsed with toluene/EtOAc (360 ml). The solution is concentrated and dried in vacuo (0.05 mbar) to yield the product as a yellow oil (2.79 g, 40%).

Provenance & Evidence