Hydrochloric Acid → 3-benzyloxycarbonyl-2,3,4,4a-tetrahydro-1H-pyrazino[1,2-a]quinoxalin-5(6H)-one

HRID 437951Notes

Reaction equation

HRID 437951 reaction equation
[C:1]([N:11]1[CH2:16][CH2:15][N:14]([C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][C:18]=2[N+:23]([O-])=O)[CH:13]([C:26]([OH:28])=O)[CH2:12]1)([O:3][CH2:4][C:5]1[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=1)=O.[OH-:29].[Na+].S(S([O-])=O)([O-])=O.[Na+].[Na+].Cl>O>[C:1]([N:11]1[CH2:16][CH2:15][N:14]2[C:17]3[C:18]([NH:23][C:26](=[O:28])[CH:13]2[CH2:12]1)=[CH:19][CH:20]=[CH:21][CH:22]=3)([O:3][CH2:4][C:5]1[CH:10]=[CH:9][CH:8]=[CH:7][CH:6]=1)=[O:29]

Participants

6

Reactant 4

HCID 313Hydrochloric AcidHCID 14798Sodium Hydroxide2×HCID 24489Sodium DithioniteHCID 121096434-Carbobenzoxy-1-(o-nitrophenyl)piperazine-2-carboxylic acid

Product 1

HCID 121096443-benzyloxycarbonyl-2,3,4,4a-tetrahydro-1H-pyrazino[1,2-a]quinoxalin-5(6H)-one

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

To a solution of 13 g. of 4-carbobenzoxy-1-(o-nitrophenyl)piperazine- 2-carboxylic acid and 11.0 g. of sodium hydroxide in 200 ml. of water is added a solution of 20 g. of sodium hydrosulfite in 200 ml. of H 2 O. The orange solution gradually turns colorless over a period of 2-3 hours. Dilute hydrochloric acid is added to bring the pH of the solution to about 3. A white precipitate forms. Stirring is continued for about 3-5 minutes, and the pH is raised to about 7 by the addition of 40% sodium hydroxide. Filtration gives 8.6 g. of product, m.p. 125°-140°. The analytical sample on recrystallization from ethyl acetate hexane gave a m.p. 167°-170°.

Workup

  1. waitis continued for about 3-5 minutes
  2. filtrationFiltration
  3. customgives 8.6 g
  4. customThe analytical sample on recrystallization from ethyl acetate hexane
  5. customgave a m.p. 167°-170°

Sources & evidence

ORD record
ord-2a9e76beb7c8421c853754d7c15abea8
Source dataset
uspto-grants-1977_06
Patent number
US04032639

Reaction notes

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