Hydrochloric Acid → 2-Amino-5-methyl-5,6,7,8-tetrahydroquinolin-5-ol

To a solution of 2-(diphenylmethyleneamino)-5-methyl-5,6,7,8-tetrahydroquinolin-5-ol (180 mg, 0.526 mmol) in THF (20 ml) was added aqueous hydrochloric acid (2.0 M, 1.00 ml, 2.0 mmol). After 20 minutes, the reaction mixture was partially concentrated under reduced pressure to a volume of approximately 2 mL. The mixture was diluted with ethyl acetate (30 mL), saturated aqueous sodium bicarbonate solution (15 mL), saturated aqueous sodium carbonate (10 mL), and brine (15 mL). The layers were separated and the aqueous layer was extracted with ethyl acetate (2×15 mL). The combined organics were dried over sodium sulfate, filtered, and concentrated under reduced pressure. The residue was purified by chromatography on silica gel (0.5-10% methanol/dichloromethane linear gradient) to yield 2-amino-5-methyl-5,6,7,8-tetrahydroquinolin-5-ol. MS ESI calc'd. for C10H15N2O [M+H]+ 179. found 179. 1H NMR (500 MHz, CDCl3) δ 7.64 (d, J=8.5 Hz, 1H), 6.38 (d, J=8.5 Hz, 1H), 4.42 (s, 2H), 2.80-2.63 (m, 2H), 2.02-1.75 (m, 5H), 1.50 (s, 3H).

1. concentrationthe reaction mixture was partially concentrated under reduced pressure to a volume of approximately 2 mL
2. additionThe mixture was diluted with ethyl acetate (30 mL), saturated aqueous sodium bicarbonate solution (15 mL), saturated aqueous sodium carbonate (10 mL), and brine (15 mL)
3. customThe layers were separated
4. extractionthe aqueous layer was extracted with ethyl acetate (2×15 mL)
5. dry with materialThe combined organics were dried over sodium sulfate
6. filtrationfiltered
7. concentrationconcentrated under reduced pressure
8. customThe residue was purified by chromatography on silica gel (0.5-10% methanol/dichloromethane linear gradient)

ORD record

ord-b082b85481ca40a89118799e6f5532ce

Source dataset

uspto-grants-2015_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US09216173B2