Hydrochloric Acid → 1,3-Dimethyl-1,2,3,4-tetrahydroquinoxaline

HRID 1702622Notes

Reaction equation

HRID 1702622 reaction equation
[CH3:1][N:2]1[C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[N:5]=[C:4]([CH3:12])[C:3]1=O.B#B.Cl>O1CCCC1.O>[CH3:1][N:2]1[C:11]2[C:6](=[CH:7][CH:8]=[CH:9][CH:10]=2)[NH:5][CH:4]([CH3:12])[CH2:3]1

Participants

6

Reactant 3

HCID 313Hydrochloric AcidHCID 3514221,3-dimethylquinoxalin-2(1H)-oneHCID 6328200Diboron

Product 1

HCID 108208921,3-Dimethyl-1,2,3,4-tetrahydroquinoxaline

Reagents, catalysts & solvents 2

HCID 962WaterSolvent2×HCID 8028TetrahydrofuranSolvent2×

Procedure

To a stirred solution of 0.2 mole (34.8 g) of 1,3-dimethyl-2-oxoquinoxaline in 300 ml of dry tetrahydrofuran was added dropwise 0.24 mole (240 ml of 1 M) diborane in tetrahydrofuran. The solution was stirred one additional hour, then heated at its reflux temperature for one day. After cooling, about 40 ml of water was added, followed by 2 equivalents of 4 N hydrochloric acid. The solution was heated at reflux for one hour, then evaporated to provide a solid residue. The residue was dissolved in water. The solution was basified and then extracted with diethyl ether. The ether was dried, then evaporated to provide an oil. Distillation provides 1,3-dimethyl-1,2,3,4-tetrahydroquinoxaline, b.p. 85° C./0.1 mm of Hg. Analysis: Calculated for C10H14N2 :%C, 74.0; %H, 8.7; %N, 17.4; Found : %C, 74.2; %H, 8.9; %N, 17.3.

Workup

  1. temperatureheated at its
  2. temperaturereflux temperature for one day
  3. temperatureAfter cooling
  4. temperatureThe solution was heated
  5. temperatureat reflux for one hour
  6. customevaporated
  7. customto provide a solid residue
  8. extractionextracted with diethyl ether
  9. dry with materialThe ether was dried
  10. customevaporated
  11. customto provide an oil
  12. distillationDistillation

Sources & evidence

ORD record
ord-d6ed17bb6e9d4652bb8935cf2b0bfc2f
Source dataset
uspto-grants-1982_09
Patent number
US04348521

Reaction notes

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