Hydrogen Bromide → 2,2,4-Trimethyl-1,2-dihydro-6-quinolinol

HRID 1779342

Reaction equation

HRID 1779342 reaction equation
C([O:3][C:4]1[CH:5]=[C:6]2[C:11](=[CH:12][CH:13]=1)[NH:10][C:9]([CH3:15])([CH3:14])[CH2:8][CH:7]2[CH3:16])C.Br.[OH-].[Na+].Cl.C(=O)(O)[O-].[Na+]>O>[OH:3][C:4]1[CH:5]=[C:6]2[C:11](=[CH:12][CH:13]=1)[NH:10][C:9]([CH3:15])([CH3:14])[CH:8]=[C:7]2[CH3:16]

Participants

7

Reactant 5

HCID 260Hydrogen BromideHCID 313Hydrochloric AcidHCID 14798Sodium HydroxideHCID 860136-Ethoxy-2,2,4-trimethyl-1,2,3,4-tetrahydroquinolineHCID 516892Sodium Bicarbonate

Product 1

HCID 5997992,2,4-Trimethyl-1,2-dihydro-6-quinolinolYield 56.3%

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

6-Ethoxy-2,2,4-trimethyl-3,4-dihydroquinoline [Ethoxyquin (70 g, 0.32 mole)], was added to 250 mL of 48% HBr, and the mixture was heated to reflux for about 1 hour. The solution was cooled and poured into water. The aqueous suspension was made basic (pH=14) by the addition of 50% aqueous NaOH. Concentrated HCl was added to adjust the pH to about 4, then the mixture was made slightly basic by the addition of saturated sodium bicarbonate solution. The mixture was extracted with EtOAc and the organic layers were dried (brine, MgSO4) and concentrated in vacuo. The thick dark oil was triturated with toluene and the insoluble residue was filtered. The crude solid was recrystallized from toluene to give the title compound as a light brown solid (mp 182°-184°, 34 g, 0.18 mole, 56%). An analytical sample was prepared by another recrystallization from toluene to provide light brown crystals, mp 182°-184°: IR (KBr) 3302, 2972, 2934, 1586, 1495, 1344, 1244, 1154, 880, 814 cm-1 ; 1H NMR (D-6 DMSO) δ 1.12 (s, 6H), 1.33 (s, 3H), 3.34 (s, 1H), 5.17 (br s, 1H), 5.26 (s, 1H), 6.28-6.42 (m, 3H); MS m/e 190 (MH+).

Workup

  1. temperaturethe mixture was heated
  2. temperatureto reflux for about 1 hour
  3. temperatureThe solution was cooled
  4. extractionThe mixture was extracted with EtOAc
  5. dry with materialthe organic layers were dried (brine, MgSO4)
  6. concentrationconcentrated in vacuo
  7. customThe thick dark oil was triturated with toluene
  8. filtrationthe insoluble residue was filtered
  9. customThe crude solid was recrystallized from toluene

Sources & evidence

ORD record
ord-9bdd04441a404ed2bbf4c6ee7b31201f
Source dataset
uspto-grants-1997_05
Patent number
US05627192

Linked notes

Loading…