Dimethyl 4-cyano-4-(3,4-dimethoxyphenyl)heptanedioate can be prepared by the following steps:A mixture of finely powdered 3,4- dimethoxyphenylacetonitrile 45 (5 g, 28.25 mmol) and TBAHSO4 (0.096 g, 0.28 mmol) in 10% aq. NaOH solution (20 ml) was stirred for 30 minutes at room temperature. A dark red colour appeared. The mixture was then cooled in an ice-bath. Methyl acrylate 239 was slowly added dropwise at 0 o C, (12.65 ml, 138.95 mmol). After 1 hour a colourless solid was formed, which was filtered and crystallized from EtOAc (7.49 g, 76% yield). Alternatively, dimethyl 4-cyano-4-(3,4-dimethoxyphenyl)heptanedioate was prepared by refluxing a mixture of 3,4- dimethoxyphenylacetonitrile (100 g, 0.564 mol) and methyl acrylate (253 ml, 2.82 mol) in the presence of Triton-B (2.35 ml, 0.006 mol, 40% solution in MeOH) in CH3CN for overnight in almost quantitative yields (197 g).
