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

HRID 2294502Notes

Reaction equation

HRID 2294502 reaction equation
[CH2:1]([Mg]Br)[CH3:2].[C:5]([O:9][C:10]([N:12]1[C:21]2[C:16](=[CH:17][CH:18]=[CH:19][CH:20]=2)[C:15](=[O:22])[CH2:14][CH2:13]1)=[O:11])([CH3:8])([CH3:7])[CH3:6].OS([O-])(=O)=O.[Na+]>CCOCC>[C:5]([O:9][C:10]([N:12]1[C:21]2[C:16](=[CH:17][CH:18]=[CH:19][CH:20]=2)[C:15]([CH2:1][CH3:2])([OH:22])[CH2:14][CH2:13]1)=[O:11])([CH3:8])([CH3:6])[CH3:7]

Participants

5

Reactant 3

HCID 516919Sodium BisulfateHCID 23433504tert-Butyl 4-oxo-3,4-dihydroquinoline-1(2H)-carboxylateHCID 178418443HCID 178418443, compound

Product 1

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

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent2×

Conditions

Temperature
-10 °C

Procedure

To a flame-dried 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, 2H), 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. temperatureto warm to rt over 10 min
  2. extractionThe resulting biphasic mixture was extracted with EtOAc (3×10 mL)
  3. dry with materialthe combined organic extracts were dried (Na2SO4)
  4. concentrationconcentrated under reduced pressure
  5. customThe residue was purified by flash chromatography (silica gel, hexanes/EtOAc, 4:1)

Sources & evidence

ORD record
ord-98f2cd9483114d3c95ddfa0fe14fb62b
Source dataset
uspto-grants-1997_11
Patent number
US05688810

Reaction notes

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