Hydrochloric Acid → 3-Benzyl-5,6,7,8-tetrahydroquinoxalin-2(1H)-one

HRID 330071Notes

Reaction equation

HRID 330071 reaction equation
[C:1]1(=O)[CH2:6][CH2:5][CH2:4][CH2:3][C:2]1=O.Cl.[NH2:10][C@H:11]([C:19]([NH2:21])=[O:20])[CH2:12][C:13]1[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=1.[OH-].[Na+].Cl.C(=O)(O)[O-].[Na+]>CO>[OH:20][C:19]1[C:11]([CH2:12][C:13]2[CH:18]=[CH:17][CH:16]=[CH:15][CH:14]=2)=[N:10][C:1]2[CH2:6][CH2:5][CH2:4][CH2:3][C:2]=2[N:21]=1

Participants

7

Reactant 5

HCID 313Hydrochloric AcidHCID 130061,2-CyclohexanedioneHCID 14798Sodium HydroxideHCID 516892Sodium BicarbonateHCID 11953719Phenylalanine amide hydrochloride

Product 1

HCID 1785173403-Benzyl-5,6,7,8-tetrahydroquinoxalin-2(1H)-oneYield 82.1%

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent2×

Procedure

A methanol (30 ml) solution of cyclohexane-1,2-dione (13.44 g, 0.12M) was added to phenylalanineamide hydrochloride (20.05 g, 0.1M) dissolved in methanol (200 ml) with cooling below -30° C., and aqueous 12.5N-NaOH (20 ml) was added dropwise thereto. The reaction mixture was stirred at below -30° C. for 30 minutes and was further stirred at room temperature for 3 hours. Conc. hydrochloric acid (25 ml) was added to the reaction mixture, and sodium bicarbonate (15 g) was added after 10 minutes stirring, the solvent then being distilled off in vacuo. The residue, to which was added water, was extracted three times with chloroform, and the extract was dried with anhydrous magnesium sulfate and concentrated in vacuo. The residue was recrystallized from acetone to obtain the product. (19.7 g, yield: 82.1%).

Workup

  1. temperaturewith cooling below -30° C.
  2. stirringwas further stirred at room temperature for 3 hours
  3. additionwas added after 10 minutes
  4. stirringstirring
  5. distillationthe solvent then being distilled off in vacuo
  6. additionThe residue, to which was added water
  7. extractionwas extracted three times with chloroform
  8. dry with materialthe extract was dried with anhydrous magnesium sulfate
  9. concentrationconcentrated in vacuo
  10. customThe residue was recrystallized from acetone
  11. customto obtain the product

Sources & evidence

ORD record
ord-72db7c37bcbc4fa48068c74312bc73c5
Source dataset
uspto-grants-1990_01
Patent number
US04894453

Reaction notes

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