Dimethyl (4-methoxy-2-nitrobenzyl)malonate → 7-Methoxy-2-oxo-1,2,3,4-tetrahydro-3-quinolinecarboxylic acid

Temperature

80 °C

10% Palladium- carbon (2.0 g) was added to an ethanol (200 ml) solution of dimethyl (4-methoxy-2-nitrobenzyl)malonate (19 g), and catalytic hydrogenation was conducted at room temperature under an atmospheric pressure for 24 hours. The reaction mixture was further stirred at 80° C. for 24 hours. The catalyst was removed by filtration, and the filtrate was concentrated. The residue was dissolved in a mixed solvent of THF (250 ml) and methanol (250 ml), to which was added dropwise 1N aqueous sodium hydroxide solution (126 ml) under ice-cooling. The reaction mixture was stirred at room temperature for 72 hours and concentrated. 1N Hydrochloric acid was added to the residue to make acidic, and the precipitated crystals were collected by filtration. The obtained crude crystals were washed with acetone to give the entitled compound (11.7 g).

1. customThe catalyst was removed by filtration
2. concentrationthe filtrate was concentrated
3. dissolutionThe residue was dissolved in a mixed solvent of THF (250 ml) and methanol (250 ml), to which
4. additionwas added dropwise 1N aqueous sodium hydroxide solution (126 ml) under ice-
5. temperaturecooling
6. stirringThe reaction mixture was stirred at room temperature for 72 hours
7. concentrationconcentrated
8. addition1N Hydrochloric acid was added to the residue
9. filtrationthe precipitated crystals were collected by filtration
10. customThe obtained crude crystals
11. washwere washed with acetone

ORD record

ord-3bf3cda12c274e63835b766fbd46b69a

Source dataset

uspto-grants-2001_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06329389B1