Tri-o-tolylphosphine → Tert-butyl 4-(7-benzo[b]furanyl)piperazine-1-carboxylate

HRID 1952763Notes

Reaction equation

HRID 1952763 reaction equation
C1(C)C=CC=CC=1P(C1C=CC=CC=1C)C1C=CC=CC=1C.CC(C)([O-])C.[Na+].[C:29]([O:33][C:34]([N:36]1[CH2:41][CH2:40][NH:39][CH2:38][CH2:37]1)=[O:35])([CH3:32])([CH3:31])[CH3:30].Br[C:43]1[C:48]2[O:49][CH:50]=[CH:51][C:47]=2[CH:46]=[CH:45][CH:44]=1>C1(C)C=CC=CC=1.[Pd].C(=CC(C=CC1C=CC=CC=1)=O)C1C=CC=CC=1.C(=CC(C=CC1C=CC=CC=1)=O)C1C=CC=CC=1>[O:49]1[CH:50]=[CH:51][C:47]2[CH:46]=[CH:45][CH:44]=[C:43]([N:39]3[CH2:40][CH2:41][N:36]([C:34]([O:33][C:29]([CH3:32])([CH3:30])[CH3:31])=[O:35])[CH2:37][CH2:38]3)[C:48]1=2

Participants

7

Reactant 4

HCID 80271Tri-o-tolylphosphineHCID 1136287-Bromo-1-benzofuranHCID 143452tert-Butyl piperazine-1-carboxylateHCID 23676156Sodium t-butoxide

Product 1

HCID 23300012Tert-butyl 4-(7-benzo[b]furanyl)piperazine-1-carboxylateYield 19.9%

Reagents, catalysts & solvents 2

HCID 1542701,5-Diphenylpenta-1,4-dien-3-one;palladiumCatalystHCID 1140TolueneSolvent

Procedure

Tri-o-tolylphosphine (1.42 g) was added to a stirred suspension of bis (dibenzylideneacetone) palladium (O) (1.4 g) in toluene (480 ml) at ambient temperature under nitrogen. Sodium tert-butoxide (16.1 g) was added, followed by N-tert-butoxycarbonylpiperazine (26.6 g) and stirring was continued at ambient temperature for 5 minutes. 7-Bromobenzo[b]furan (23.3 g) was added and the stirred mixture was heated under reflux for 20 hours and then cooled to ambient temperature. The organic solution was decanted from the palladium residues, then washed with brine (500 ml) and dried (MgSO4). The solvent was removed in vacuo and the residue was purified by flash column chromatography over silica using a 1:9 mixture of ether and petroleum ether (b.p. 60-80° C.) as eluant to give tert-butyl 4-(7-benzo[b]furanyl)piperazine-1-carboxylate (7.12 g) as a pale yellow solid, m.p. 98-100° C.

Workup

  1. temperaturethe stirred mixture was heated
  2. temperatureunder reflux for 20 hours
  3. customThe organic solution was decanted from the palladium residues
  4. washwashed with brine (500 ml)
  5. dry with materialdried (MgSO4)
  6. customThe solvent was removed in vacuo
  7. customthe residue was purified by flash column chromatography over silica using
  8. additiona 1:9 mixture of ether and petroleum ether (b.p. 60-80° C.) as eluant

Sources & evidence

ORD record
ord-3a202026d9a14fa6b322f144057b5465
Source dataset
uspto-grants-2000_09
Patent number
US06114334

Reaction notes

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