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

HRID 918165Notes

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 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 2 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 1 hour
additionis poured into about 600 ml
temperatureheated on a steam bath for 2 hours
filtrationfiltered
customThe solid product is isolated by filtration
washwashed with water and ethanol
customrecrystallized from N,N-dimethylformamide

Sources & evidence

ORD record: ord-1d9920f3b60141c2acd883b33b45e50c
Source dataset: uspto-grants-1976_07
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US03969463

Reaction notes

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