Diethyl Ether → (R/S)-1-tert-Butyloxycarbonyl-4-ethyl-1,2,3,4-tetrahydro4-hydroxyquinoline

HRID 1939590Notes

Reaction equation

HRID 1939590 reaction equation
[C:1]([O:5][C:6]([N:8]1[C:17]2[C:12](=[CH:13][CH:14]=[CH:15][CH:16]=2)[C:11](=[O:18])[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:3])[CH3:2].OS([O-])(=O)=O.[Na+].[CH3:25][CH2:26]OCC>>[C:1]([O:5][C:6]([N:8]1[C:17]2[C:12](=[CH:13][CH:14]=[CH:15][CH:16]=2)[C:11]([CH2:25][CH3:26])([OH:18])[CH2:10][CH2:9]1)=[O:7])([CH3:4])([CH3:2])[CH3:3]

Participants

4

Reactant 3

HCID 3283Diethyl EtherHCID 516919Sodium BisulfateHCID 23433504tert-Butyl 4-oxo-3,4-dihydroquinoline-1(2H)-carboxylate

Product 1

HCID 23433517(R/S)-1-tert-Butyloxycarbonyl-4-ethyl-1,2,3,4-tetrahydro4-hydroxyquinolineYield 71%

Conditions

Temperature
-10 °C

Procedure

To a flame-dried b 25-mL rb flask containing ethylmagnesium bromide (4.0 mL of a 3.0M solution in Et2O, 12.0 mmol, 3.0 equiv), at -10° C. was added dropwise a solution of 1-tert-butyloxycarbonyl-1,2,3,4-tetrahydro-4-quinolone (1.0 g, 4.0 mmol) in Et2O (4 mL). The reaction mixture was stirred at -10° C. for 15 min, then allowed to warm to rt over 10 min. A 1.0M solution of NaHSO4 (10 mL) was then rapidly added. The resulting biphasic mixture was extracted with EtOAc (3×10 mL), and the combined organic extracts were dried (Na2SO4) and concentrated under reduced pressure. The residue was purified by flash chromatography (silica gel, hexanes/EtOAc, 4:1), affording 800 mg (71%) of the desired product as a clear yellow oil (Rf 0.14, hexanes/EtOAc, 4:1). Data for 1-tert-butoxycarbonyl-4-ethyl-1,2,3,4-tetrahydro-4-hydroxyquinoline: 1H NMR (400 MHz, CDCl3) 7.68 (d, 1H, J=8.4, 8-H), 7.47 (dd, 1H, J=7.9, 1.7, 5-H), 7.21 (ddd, 1H, J=7.4, 7.4, 1.6, 6-H), 7.09 (ddd, 1H, J=7.8, 7.8, 1.1, 7-H), 4.03 (ddd, 1H, J=12.9, 7.1, 4.7, 2-H), 3.47 (ddd, 1H, J=13.1, 8.6, 4.3; 2-H), 2.11 (ddd, 1H, J=13.5, 8.6, 4.8, 3-H), 1.86 (m, 3H, 3-H, CH2CH3), 1.52 [s, 9H, C(CH3)3 ], 0.89 (t, 3H, J=7.5, CH3).

Workup

  1. customTo a flame-dried b 25-mL rb flask
  2. additioncontaining ethylmagnesium bromide (4.0 mL of a 3.0M solution in Et2O, 12.0 mmol, 3.0 equiv), at -10° C.
  3. temperatureto warm to rt over 10 min
  4. extractionThe resulting biphasic mixture was extracted with EtOAc (3×10 mL)
  5. dry with materialthe combined organic extracts were dried (Na2SO4)
  6. concentrationconcentrated under reduced pressure
  7. customThe residue was purified by flash chromatography (silica gel, hexanes/EtOAc, 4:1)

Sources & evidence

ORD record
ord-7ff6c053fedb46f781126cdfc8c903b9
Source dataset
uspto-grants-1997_12
Patent number
US05696133

Reaction notes

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