123387-53-1

635-46-1

24424-99-5

123387-53-1

GENERAL STEPS: 1,2,3,4-tetrahydroquinoline (626 mg, 4.7 mmol) was dissolved in acetonitrile (15 mL) under nitrogen protection, and triethylamine (1.3 mL, 9.3 mmol) and 4-dimethylaminopyridine (DMAP, 112 mg, 0.19 mmol) were added sequentially. Subsequently, di-tert-butyl dicarbonate (1.181 g, 5.4 mmol) was slowly added to the reaction system. The reaction mixture was stirred at room temperature for 1.5 hours and then warmed up to 55 °C to continue the reaction overnight. After completion of the reaction, the mixture was cooled to room temperature and concentrated under reduced pressure to remove the solvent. The residue was extracted by partitioning with ethyl acetate (25 mL) and 1M hydrochloric acid (25 mL). The organic phase was separated and washed sequentially with 1M hydrochloric acid (2 x 25 mL) and saturated saline (25 mL). The organic phase was dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The crude product was purified by silica gel fast column chromatography (Combiflash system, elution gradient: 0% to 40% ethyl acetate/hexane) to afford tert-butyl 3,4-dihydroquinoline-1(2H)-carboxylate (139 mg, 13% yield) as a colorless oil.