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

HRID 597521Notes

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 three hours. Polyphosphoric acid (200 g.) is added, and the mixture is heated gradually to 220° C. then maintained at 220° C. for one 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 three hours
temperaturethen maintained at 220° C. for one hour
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-0e66ceb581544733b3ae21efff3a4b0e
Source dataset: uspto-grants-1977_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04014877

Reaction notes

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