Synthesis
a) To a solution of ethyl 2-cyclohexanone carboxylate (18.9 mL, 118 mmol) in methanol (120 mL) was added ammonium carbamate (9.20 g, 118 mmol). The reaction mixture was stirred at room temperature for 1 hour until the ammonium carbamate was completely dissolved. After continuing to stir the reaction mixture for 1 h, the volatile solvent was removed by distillation under reduced pressure to afford ethyl 2-amino-1-cyclohexene-1-carboxylate as a white to pale yellow solid (19.9 g, quantitative yield). The product was characterized by 1H NMR (400 MHz, CDCl3): δ 1.28 (t, J = 7.2 Hz, 3H), 1.57-1.71 (m, 4H), 2.21 (t, J = 6.1 Hz, 2H), 2.26 (t, J = 6.1 Hz, 2H), 4.15 (q, J = 7.2 Hz, 2H), 6.06 (br s, 2H) .
References
[1] Patent: WO2013/26900, 2013, A1. Location in patent: Page/Page column 60
[2] New Journal of Chemistry, 2005, vol. 29, # 6, p. 769 - 772
[3] Tetrahedron Letters, 2013, vol. 54, # 9, p. 1133 - 1136
[4] Bioorganic and Medicinal Chemistry, 2014, vol. 22, # 14, p. 3654 - 3669
[5] Chemistry of Heterocyclic Compounds, 2006, vol. 42, # 6, p. 765 - 775
