Methane → 6,7-dihydro-9-methoxy-1-oxo-1H,5H-benzo[ij]quinolizine-2-carboxylic acid

HRID 1287876Notes

Reaction equation

C(O[CH:4]=[C:5]([C:11]([O:13]CC)=O)[C:6]([O:8]CC)=[O:7])C.[CH3:16][O:17][C:18]1[CH:19]=[C:20]2[C:25](=[CH:26][CH:27]=1)[NH:24][CH2:23][CH2:22][CH2:21]2.[OH-].[Na+].C>O>[CH3:16][O:17][C:18]1[CH:27]=[C:26]2[C:25]3[N:24]([CH:4]=[C:5]([C:6]([OH:8])=[O:7])[C:11]2=[O:13])[CH2:23][CH2:22][CH2:21][C:20]=3[CH:19]=1

Participants

Conditions

Temperature: 220 °C

Procedure

Diethyl ethoxymethylenemalonate (43.2 g., 0.20 mole) and 6-methoxytetrahydroquinoline (32.6 g., 0.20 mole) are mixed and heated at 125°-130° C. for 3 hours. Polyphosphoric acid (200 g.) is as added, and the mixture is heated gradually to 220° C. then maintained at 220° c. for 1 hour. The mixture containing the product ester of Formula III is poured into about 600 ml. of water, then made basic with 40 percent sodium hydroxide solution and heated on a steam bath for two hours. The solution is treated with decolorizing charcoal, filtered and acidified. The solid product is isolated by filtration, washed with water and ethanol, then recrystallized from N,N-dimethylformamide to give 6,7-dihydro-9-methoxy-1-oxo-1H,5H-benzo[ij]quinolizine-2-carboxylic acid, m.p. 253°-257° C.

Workup

temperatureheated at 125°-130° C. for 3 hours
additionas added
temperaturethen maintained at 220° c
additionis poured into about 600 ml
temperatureheated on a steam bath for two hours
filtrationfiltered
customThe solid product is isolated by filtration
washwashed with water and ethanol
customrecrystallized from N,N-dimethylformamide

Sources & evidence

ORD record: ord-9af346842f51492db9cfb014ec756086
Source dataset: uspto-grants-1976_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US03985882

Reaction notes

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