反应详情

To a solution of ethyl iso-cyanoacetate (8) (10 g, 88.4 mmol) in absolute ethanol (100 mL) at 0° C. under N2 atmosphere was added dimethoxymethyl dimethyl-amine (9) (23.4 mL, 176.8 mmol.) dropwise while stirring was continued at room temperature for 12 h. The reaction mixture was concentrated under reduced pressure to remove ethanol. The residue (crude mass, brown color) was purified by column chromatography over neutral alumina using 3 to 4% ethyl acetate in hexane as eluant. Solvent fractions were concentrated under reduced pressure and low temperature (to avoid polymerization of compound) to furnish compound 5 (11.6 g, 78%) as pale orange liquid which was solidified on cooling at 4° C.

1. concentrationThe reaction mixture was concentrated under reduced pressure
2. customto remove ethanol
3. customThe residue (crude mass, brown color) was purified by column chromatography over neutral alumina using 3 to 4% ethyl acetate in hexane as eluant
4. concentrationSolvent fractions were concentrated under reduced pressure and low temperature (to avoid polymerization of compound)