Potassium Carbonate → benzyl (9aS)-4-oxohexahydropyrazino[2,1-c][1,4]oxazine-8(1H)-carboxylate

HRID 2063316Notes

Reaction equation

HRID 2063316 reaction equation
Br[CH2:2][C:3]([N:5]1[CH2:10][CH2:9][N:8]([C:11]([O:13][CH2:14][C:15]2[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=2)=[O:12])[CH2:7][C@H:6]1[CH2:21][OH:22])=[O:4].C(=O)([O-])[O-].[K+].[K+]>C1(C)C=CC=CC=1>[O:4]=[C:3]1[CH2:2][O:22][CH2:21][C@@H:6]2[CH2:7][N:8]([C:11]([O:13][CH2:14][C:15]3[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=3)=[O:12])[CH2:9][CH2:10][N:5]12

Participants

4

Reactant 2

HCID 11430Potassium CarbonateHCID 16124473benzyl (3S)-4-(bromoacetyl)-3-(hydroxymethyl)piperazine-1-carboxylate

Product 1

HCID 16124472benzyl (9aS)-4-oxohexahydropyrazino[2,1-c][1,4]oxazine-8(1H)-carboxylateYield 23%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

Benzyl (3S)-4-(bromoacetyl)-3-(hydroxymethyl)piperazine-1-carboxylate (1.1 g, 2.9 mmol was dissolved in toluene (25 mL) and to the resultant solution was added potassium carbonate (4.0 g, 28.8 mmol). The mixture was heated to reflux overnight, cooled to RT and then the solids were filtered off. The solvent was removed by evaporation and the product was purified by chromatography on silica gel (methanol-methylene chloride 1% to 10%). There was obtained 0.19 g (23%) of benzyl (9aS)-4-oxohexahydropyrazino[2,1-c][1,4]oxazine-8(1H)-carboxylate as a colorless oil. 1H NMR (500 MHz, CDCl3): 2.6-3.0 (m, 3H), 3.4-3.6 (m, 2H), 4.0 (d, 1H), 4.1-4.3 (m, 4H), 4.5 (d, 1H), 5.1 (s, 2H), 7.2-7.4 (m, 5H).

Workup

  1. temperatureThe mixture was heated
  2. temperatureto reflux overnight
  3. filtrationthe solids were filtered off
  4. customThe solvent was removed by evaporation
  5. customthe product was purified by chromatography on silica gel (methanol-methylene chloride 1% to 10%)

Sources & evidence

ORD record
ord-b93b373c571640c19ab4ed23adddc201
Source dataset
uspto-grants-2012_10
Patent number
US08288370B2

Reaction notes

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