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

HRID 615431Notes

Reaction equation

HRID 615431 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 is added dropwise 0.24 mole (240 ml of 1 M) diborane in tetrahydrofuran. The solution is stirred one additional hour, then heated at its reflux temperature for one day. After cooling, about 40 ml of water is added, followed by 2 equivalents of 4N hydrochloric acid. The solution is heated at reflux for one hour, then evaporated to provide a solid residue. The residue is dissolved in water. The solution is basified and then extracted with diethyl ether. The ether is 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 is 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 is dried
  10. customevaporated
  11. customto provide an oil
  12. distillationDistillation

Sources & evidence

ORD record
ord-150928bac4844f2f9d63314aa78b1a3e
Source dataset
uspto-grants-1985_02
Patent number
US04499270

Reaction notes

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