Hydrochloric Acid → 5-Ethoxyimino-4-hydroxy-5,6,7,8-tetrahydroquinoline-3-carboxylic Acid

HRID 1680532Notes

Reaction equation

C([O:3][C:4]([C:6]1[CH:7]=[N:8][C:9]2[CH2:10][CH2:11][CH2:12][C:13](=[N:17][O:18][CH2:19][CH3:20])[C:14]=2[C:15]=1[OH:16])=[O:5])C.Cl>[OH-].[Na+].C(O)C>[CH2:19]([O:18][N:17]=[C:13]1[CH2:12][CH2:11][CH2:10][C:9]2[N:8]=[CH:7][C:6]([C:4]([OH:5])=[O:3])=[C:15]([OH:16])[C:14]1=2)[CH3:20]

Participants

Conditions

Temperature: 90 °C

Procedure

5-Ethoxyimino-4-hydroxy-5,6,7,8-tetrahydroquinoline-3-carboxylic acid ethyl ester (2.0 g) was dissolved in a mixture of 20 ml of 1 N sodium hydroxide and 10 ml of ethyl alcohol. The resulting reaction mixture was stirred at 90° C. for 2 hours. Under cooling with ice, the reaction mixture was adjusted to pH 4 with dilute hydrochloric acid. The crystals so precipitated were separated by filtration to obtain a yield of 0.95 g of the desired compound. This compound melted (and decomposed) at 225°-228° C. (uncorrected values). Its infrared absorption spectrum (KBr tablet) had absorption peaks at 3440, 2910, 1690, 1640, 1400, 1060, and 825 cm-1, and its n.m.r. spectrum (CF3COOH, 60MC, TMS) had signals at δ values of 1.57 (3H, t, J=7.5 Hz), 2.0-2.6 (2H, m), 3.0-3.5 (4H, m), 4.59 (2H, q, J=7.5 Hz), and 8.94 (1H, s).

Workup

customThe resulting reaction mixture
temperatureUnder cooling with ice
customThe crystals so precipitated
customwere separated by filtration

Sources & evidence

ORD record: ord-d279f5fdc70547a486aeaaf244e1ec9d
Source dataset: uspto-grants-1981_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US04273932

Reaction notes

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