Trifluoroacetic acid → methyl (2S)-2-amino-3-(1,2,3,4-tetrahydroquinolin-6-yl)propanoate

Participants

Reaction Conditions

Reaction Steps

To a solution of #214 (750 mg, 2.25 mmol, 1 eq.) in dichloromethane (20 mL) was added dropwise trifluoracetic acid (2 mL) at 0° C. and then the solution was stirred at 20° C. overnight. The reaction mixture was concentrated in vacuo and the residue was dissolved in water (20 mL). The solution was basified with sodium carbonate and extracted with ethyl acetate/tetrahydrofuran (30 mL×3). The organic phase was dried over sodium sulfate and concentrated in vacuo to afford #215 (450 mg, 85%) as a yellow oil. 1H NMR (400 MHz, CDCl3): δ 6.70 (d, 2H), 6.40 (m, 1H), 3.73 (s, 3H), 3.67 (m, 1H), 3.30 (m, 2H), 2.96 (m, 1H), 2.75 (m, 3H), 1.96 (m, 2H), 1.50 (br, 2H), 1.26 (br, 1H), HPLC (Protocol Y): m/z 235.14 [M+H+] retention time=4.35 minutes (purity >96%). Chiral HPLC retention time: 5.71 min (purity=98%). (Column: Chiralcel OJ-H, 150×4.6 mm, 5 μm; Mobile phase: ethanol (0.05% diethylamine) in CO2 from 5% to 40% over 15 minutes; Flow rate: 2.5 mL/minute.

Provenance & Evidence