[CH3:1][N:2]([CH3:9])[C:3](=[O:8])[C:4]([O:6][CH3:7])=[O:5].[CH2:10]([CH:12]([CH2:15][CH2:16][CH2:17][CH3:18])CO)[CH3:11].S(=O)(=O)(O)O>CO>[CH3:1][N:2]([CH3:9])[C:3](=[O:8])[C:4]([O:6][CH2:7][CH:12]([CH2:10][CH3:11])[CH2:15][CH2:16][CH2:17][CH3:18])=[O:5]In a 1,000 mL reactor, are mixed at 20-25° C., methyl 2-(dimethylamino)-2-oxoacetate (compound 1) (390 g, 2.98 mol), 2-ethyl-hexan-1-ol (464 g, 3.5 mol) and 98% sulfuric acid (66 g, 0.67 mol). The temperature of the mixture is brought to and maintained at 80° C. for 24 hours. The progression of the reaction is tracked by gas chromatography analysis. At the end of the reaction, the methanol formed is removed from the reaction medium by distillation under reduced vacuum (Pmin=150 mbars) and an aqueous solution of sodium hydrogencarbonate is then added to the reaction medium so that the final pH is 7. The organic phase is separated from the aqueous phase. The latter is counter-extracted with 500 mL of dichloromethane. The organic phases are collected and then the reaction medium is concentrated in order to remove the dichloromethane. To the residue, are added 5 g of potassium carbonate and the thereby obtained medium is then distilled under partial vacuum (Tbp 150° C., P<1 mbar). The expected product is obtained with a purity of more than 98% (578 g).
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