Synthesis
The general procedure for the synthesis of tert-butyl (1,2,3,4-tetrahydroquinolin-3-yl)carbamate from the compound (CAS:219862-13-2) is as follows: to a solution of MeOH (150 mL) of 3-quinolinylcarbamic acid was added a solution of MeOH (18 mL) of 1,1-dimethylethyl ester (6.0 g, 24.56 mmol). The reaction mixture was deoxygenated by argon bubbling for 15 minutes and then palladium hydroxide (20% palladium/carbon, 1.2 g) was added. The resulting suspension was subjected to hydrogenation under 45 psi hydrogen pressure for 16 h. Upon completion of the reaction, the catalyst was removed by filtration. The filtrate was concentrated and the residue was dissolved in dichloromethane (CH2Cl2). The resulting dichloromethane solution was washed sequentially with saturated aqueous sodium bicarbonate (NaHCO3) and saturated aqueous sodium chloride (NaCl), dried over anhydrous sodium sulfate (Na2SO4) and concentrated. Finally, the residue was purified by silica gel column chromatography with gradient elution (0 to 50%) of ethyl acetate (EtOAc) in hexane to afford the target product 1A (4.6 g, 75% yield) as a white solid.
References
[1] Patent: US2006/160850, 2006, A1. Location in patent: Page/Page column 9
[2] Patent: US2012/65204, 2012, A1. Location in patent: Page/Page column 30; 31
[3] Patent: WO2012/31993, 2012, A1. Location in patent: Page/Page column 87
[4] Bioorganic and Medicinal Chemistry Letters, 2005, vol. 15, # 7, p. 1895 - 1899
