2-Ethylquinoxaline → HCID 44603669, compound

HRID 520777Notes

Reaction equation

HRID 520777 reaction equation
[CH2:1]([C:3]1[CH:12]=[N:11][C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[N:4]=1)[CH3:2]>C1(C)C=CC=CC=1>[CH2:1]([C@H:3]1[CH2:12][NH:11][C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[NH:4]1)[CH3:2]

Participants

3

Reactant 1

HCID 123611872-Ethylquinoxaline

Product 1

HCID 44603669HCID 44603669, compoundYield 96%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Conditions

Temperature
40 °C

Procedure

To an argon-purged pressure-resistant glass vessel (100 mL) equipped with a magnetic stir bar, RuCl[(R)-daipena][(R)-dm-segphos] (2.0 mg, 1.7 μmol) and KO(t-Bu) (9.2 mg, 0.082 mmol) were added, and the vessel was purged with argon again. To this vessel, a toluene (1.7 mL) solution containing 2-ethylquinoxaline (269.4 mg, 1.70 mmol) and being degassed by the freeze-pump-thaw technique in advance was added by pressure transfer using a cannula. An operation in which hydrogen was introduced into the pressure-resistant vessel up to 0.8 MPa and then released was repeated 10 times to completely substitute the inside with hydrogen. Then, hydrogen was introduced up to 2.0 MPa, and the vessel was stirred in a water bath at 40° C. for 25 hours. After hydrogen was released, the solution was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (hexane:ethyl acetate=5:1 to 3:1 to 1:1) to obtain (S)-2-ethyl-1,2,3,4-tetrahydroquinoxaline (264.3 mg, 96%). A result of an analysis conducted by high performance liquid chromatography (column: CHIRALCEL OD-H, mobile phase: hexane:IPA=90:10, 1 mL/min) showed that the optical purity of this product was 99% ee or higher.

Workup

  1. customTo an argon-purged pressure-resistant glass vessel (100 mL)
  2. customequipped with a magnetic stir bar
  3. customthe vessel was purged with argon again
  4. custombeing degassed by the freeze-pump-thaw technique in advance
  5. additionwas added by pressure transfer
  6. additionAn operation in which hydrogen was introduced into the pressure-resistant vessel up to 0.8 MPa
  7. additionThen, hydrogen was introduced up to 2.0 MPa
  8. concentrationthe solution was concentrated under reduced pressure
  9. customthe residue was purified by silica gel column chromatography (hexane:ethyl acetate=5:1 to 3:1 to 1:1)

Sources & evidence

ORD record
ord-32aa9811f6f442779467e10e003eb9e9
Source dataset
uspto-grants-2016_05
Patent number
US09328079B2

Reaction notes

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