[CH2:1]=O.[C:3]([O:9][CH2:10][CH3:11])(=[O:8])[CH2:4][C:5](O)=O.[CH3:12][NH:13][CH3:14]>O>[CH3:12][N:13]([CH2:5][C:4](=[CH2:1])[C:3]([O:9][CH2:10][CH3:11])=[O:8])[CH3:14]Aqueous formaldehyde (161 ml, 37%) was added slowly to a solution of ethyl hydrogen malonate (132g) and dimethylamine (350 ml, 26% aqueous) in water (150 ml) at 15° C. The mixture was stirred at 15° C for 30 minutes, heated slowly to 40° C and stirred for a further 30 minutes. Decarboxylation commenced at 26° C. After cooling, the organic material which had separated as a colourless oil was extracted with ether (3 × 250 ml). The ether extracted was dried over anhydrous sodium sulphate and evaporated at atmospheric pressure. The residue was shown to be a mixture by the appearance of two carbonyl peaks (1740 cm-1 and 1720 cm-1) in the infrared spectrum. The mixture was distilled under vacuum to give ethyl 2-dimethylaminomethylacrylate (50g, 32% boiling point 34° C/0.7mm; νc=o 1722cm-1) and ethyl 1,3-bis (dimethylamino) propane-2-carboxylate (87g, 43%, boiling point 58° C/0. 8mm;νc=o 1740 cm-1).
Wird geladen…
