Benzaldehyde (Acros Organics)
Allylamine (Merck)
Cyclohexyl isocyanide (Merck)
3-Nitropropionic acid (Sigma)
MeOH

A solution of  benzaldehyde (1.70 mmol, 0.172 mL), allylamine (1.70 mmol, 0.128 mL), cyclohexyl isocyanide (1.70 mmol, 0.211 mL) and 3-nitropropionic acid (1.70 mmol, 0.202 g) in 10 mL MeOH was stirred at room temperature under nitrogen atmosphere. After 28 h, the solution was concentrated under reduced pressure to leave a pale yellow solid. The residue was washed with cold Et₂O (3 x 20 mL) to give pure title compound as a white solid (475 mg, 75% yield, mp 190-192 ^°C, R_f= 0.44 (ethyl acetate-hexane; 1 : 1).  ¹H and ¹³C NMR spectra showed title compound is a mixture of two rotamers in an approximately 1:4.5 ratio.

IR-ATR: 3258, 3084, 2926, 2855, 1638, 1629, 1547 cm^-1.
¹H NMR (400 MHz, DMSO-d₆): (both rotamers) ppm = 8.30 (0.18H, d, NH, J= 7.71 Hz), 8.21 (0.82H, d, NH, J= 7.71 Hz), 7.40-7.28 (3H, m, aromatic CH), 7.22 (2H, d, aromatic CH, J= 7.08 Hz), 6.12 (0.82H, s, CH-Ar), 5.65 (0.18H, s, CH-Ar), 5.45-5.37 (1H, m, CH₂=CH), 5.02 (1H, appear d, CH₂=CH, J=17.39 Hz), 4.95 (1H, dd, CH₂=CH, J= 1.12, 10.40 Hz), 4.75-4.72 (2H, m, CH₂NO₂), 4.04 (2H, m, CH₂=CHCH₂), 3.60-3.55 (1H, m, CHNH), 3.05 (2H, t, CH₂CH₂NO₂, J=5.23Hz), 1.75-1.62 (4H, m, cyclohexyl CH₂), 1.55-1.52 (1H, m, cyclohexyl CH₂), 1.30-1.04 (5H, m, cyclohexyl CH₂).
¹³C NMR (100 MHz, DMSO-d₆): (both rotamers) ppm = 170.17, 169.24, 167.95, 167.34, 136.47, 136.13, 134.83, 134.27, 128.80, 128.47, 128.41, 128.02, 127.84, 115.85, 115.23, 70.53, 62.28, 59.66, 47.75, 47.65, 47.31, 46.87, 32.17, 32.05, 30.03, 25.11, 24.53, 24.43.

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