Lawesson's reagent → Piperazine, 1-[thioxo(3,4,5-trimethoxyphenyl)methyl]-

HRID 2108092Notes

Reaction equation

HRID 2108092 reaction equation
[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:14]=[C:15]([O:19][CH3:20])[C:16]=1[O:17][CH3:18])[C:6]([N:8]1[CH2:13][CH2:12][NH:11][CH2:10][CH2:9]1)=O.COC1C=CC(P2(SP(C3C=CC(OC)=CC=3)(=S)S2)=[S:30])=CC=1>C1C=CC=CC=1>[CH3:1][O:2][C:3]1[CH:4]=[C:5]([CH:14]=[C:15]([O:19][CH3:20])[C:16]=1[O:17][CH3:18])[C:6]([N:8]1[CH2:13][CH2:12][NH:11][CH2:10][CH2:9]1)=[S:30]

Participants

4

Reactant 2

HCID 87949Lawesson's reagentHCID 28742041-(3,4,5-Trimethoxybenzoyl)piperazine

Product 1

HCID 3054030Piperazine, 1-[thioxo(3,4,5-trimethoxyphenyl)methyl]-Yield 61.5%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

A mixture of 1-(3,4,5-trimethoxybenzoyl)piperazine (2.0 g), a Lawesson reagent ([2,4-bis(4-methoxypehnyl)-1,3-dithia-2,4-diphosphethane-2,4-disulfide]) (2.9 g) and benzene (20 ml) is heated under reflux for 30 minutes. After cooling, insolubles are filtered off, and the filtrate is concentrated under reduced pressure. To the residue is added 1N hydrochloric acid (100 ml) and following ethyl acetate (50 ml), and the mixture is shaken. The aqueous layer is separated, and to the aqueous layer is added a 1N aqueous solution of sodium hydroxide to make the system alkaline, followed by extraction with methylene chloride. The organic layer is washed with water and dried, then the solvent is distilled off. The residue is recrystallized from ethyl acetate - hexane to afford 1-(3,4,5-trimethoxythiobenzoyl)piperazine as pale yellow prisms (1.3 g), m.p. 116°-118° C.

Workup

  1. temperatureunder reflux for 30 minutes
  2. temperatureAfter cooling
  3. filtrationinsolubles are filtered off
  4. concentrationthe filtrate is concentrated under reduced pressure
  5. additionTo the residue is added 1N hydrochloric acid (100 ml)
  6. customThe aqueous layer is separated
  7. additionto the aqueous layer is added a 1N aqueous solution of sodium hydroxide
  8. extractionfollowed by extraction with methylene chloride
  9. washThe organic layer is washed with water
  10. customdried
  11. distillationthe solvent is distilled off
  12. customThe residue is recrystallized from ethyl acetate - hexane

Sources & evidence

ORD record
ord-c1a01d7b040247329fb3b687ed181529
Source dataset
uspto-grants-1990_06
Patent number
US04937246

Reaction notes

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