Piperazine → N-Desmethylzopiclone

HRID 27075Notes

Reaction equation

HRID 27075 reaction equation
[NH:1]1[CH2:6][CH2:5][NH:4][CH2:3][CH2:2]1.[Cl:7][C:8]1[CH:9]=[CH:10][C:11]([N:14]2[CH:22]([O:23][C:24]([O:26]C3C=CC=CC=3)=O)[C:21]3[C:16](=[N:17][CH:18]=[CH:19][N:20]=3)[C:15]2=[O:33])=[N:12][CH:13]=1>C(#N)C.C(Cl)Cl>[Cl:7][C:8]1[CH:9]=[CH:10][C:11]([N:14]2[CH:22]([O:23][C:24]([N:1]3[CH2:6][CH2:5][NH:4][CH2:3][CH2:2]3)=[O:26])[C:21]3[C:16](=[N:17][CH:18]=[CH:19][N:20]=3)[C:15]2=[O:33])=[N:12][CH:13]=1

Participants

5

Reactant 2

HCID 4837PiperazineHCID 23343640Carbonic acid, 6-(5-chloro-2-pyridinyl)-6,7-dihydro-7-oxo-5H-pyrrolo(3,4-b)pyrazin-5-yl phenyl ester

Product 1

HCID 162892N-DesmethylzopicloneYield 37.8%

Reagents, catalysts & solvents 2

HCID 6342AcetonitrileSolventHCID 6344DichloromethaneSolvent

Conditions

Temperature
20 °C

Procedure

Anhydrous piperazine (86 g.) is added to a suspension of 6-(5-chloropyrid-2-yl)-7-oxo-5-phenoxycarbonyloxy-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine (76.4 g.) in acetonitrile (760 cc.). The reaction mixture is stirred for 5 hours at a temperature of about 20° C. and then the insoluble product is filtered off, washed with acetonitrile (3×25 cc.) and with diisopropyl ether (50 cc.). After drying, a product (30.8 g.) is obtained and is dissolved in methylene chloride (750 cc.). A small amount of insoluble matter is removed by treating the solution with decolourising charcoal (2 g.). After filtration, the solution is concentrated to dryness under reduced pressure. 6-(5-Chloropyrid-2-yl)-7-oxo-5-(piperazin-1-yl)carbonyloxy-6,7-dihydro-5H-pyrrolo[3,4-b]pyrazine (28.3 g.), which melts at 205° C., is thus obtained.

Workup

  1. filtrationthe insoluble product is filtered off
  2. washwashed with acetonitrile (3×25 cc.) and with diisopropyl ether (50 cc.)
  3. customAfter drying
  4. customa product (30.8 g.) is obtained
  5. customA small amount of insoluble matter is removed
  6. additionby treating the solution with decolourising charcoal (2 g.)
  7. filtrationAfter filtration
  8. concentrationthe solution is concentrated to dryness under reduced pressure

Sources & evidence

ORD record
ord-e701cf5cd05646aa9793784b20d814f2
Source dataset
uspto-grants-1980_09
Patent number
US04220646

Reaction notes

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