Benzylamine → 4-(1-Benzylamino-ethylidene)-pent-2-enedioic acid dimethyl ester

Reaction equation

[CH2:1]([NH2:8])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.[CH3:9][O:10][C:11](=[O:16])[CH2:12][C:13](=O)[CH3:14].[CH3:17][O:18][C:19](=[O:22])[C:20]#[CH:21]>CO>[CH3:17][O:18][C:19](=[O:22])[CH:20]=[CH:21][C:12](=[C:13]([NH:8][CH2:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1)[CH3:14])[C:11]([O:10][CH3:9])=[O:16]

Participants

Procedure

Benzyl amine (2.0 mL, 18.7 mmol) was dissolved in MeOH (60 mL). 3-Oxo-butyric acid methyl ester (2.4 mL, 22.4 mmol) was added and the mixture was refluxed for 2 h. The mixture was cooled slightly, and propynoic acid methyl ester (2.5 mL, 28 mmol) was added. The mixture was then refluxed for 48 h. The solvent was evaporated, and the residual oil was recrystallized with MeOH to give 3.7 g of the title compound as a pale yellow solid. 1H NMR (CDCl3, 200 MHz): 8=10.94 (br s, 1H), 7.75 (d, 1H, J=15.4 Hz), 7.20-7.45 (m, 5H), 6.09 (d, 1H, J=15.4 Hz), 4.58 (d, 1H, J=6.2 Hz), 3.78 (s, 3H), 3.74 (s, 3H), 2.27 (s, 3H).