Methyl acetoacetate → 4-[1-(4-Cyano-benzylamino)-ethylidene]-pent-2-enedioic acid dimethyl ester

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Reaction Steps

A mixture of 4-cyanobenzyl amine (3 g, 22.7 mmol) and 3-oxo-butyric acid methyl ester (2.94 mL, 27.2 mmol) in MeOH (80 mL) was refluxed for 2 h. Propynoic acid methyl ester (3.03 mL, 34 mmol) was added, and the resulting mixture was refluxed for 48 h. After cooling to r.t., the solvent was evaporated, and the crude residue was recrystallized from MeOH to give 3.35 g of the title compound as a light yellow solid. 1H NMR (CDCl3, 200 MHz): δ=10.97 (br s, 1H), 7.72 (d, 1H, J=15.4 Hz), 7.67 (d, 2H, J=8.8 Hz), 7.37 (d, 2H, J=8.4 Hz), 6.11 (d, 1H, J=15.8 Hz), 4.63 (d, 2H, J=6.0 Hz), 3.79 (s, 3H), 3.73 (s, 3H), 2.21 (s, 3H).

Provenance & Evidence