1-Piperazinecarboxylic acid, ethyl ester → Ethyl 4-(4-phenyl-2-thienyl)piperazine-1-carboxylate

HRID 2263053Notes

Reaction equation

Br[C:2]1[S:3][CH:4]=[C:5]([C:7]2[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=2)[CH:6]=1.BrC1SC=CC=1C1C=CC=CC=1.[CH2:25]([O:27][C:28]([N:30]1[CH2:35][CH2:34][NH:33][CH2:32][CH2:31]1)=[O:29])[CH3:26].CC(C)([O-])C.[Na+].C1(P(C2C=CC=CC=2)C2C=CC3C(=CC=CC=3)C=2C2C3C(=CC=CC=3)C=CC=2P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>C1(C)C=CC=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.[Pd].[Pd]>[C:7]1([C:5]2[CH:6]=[C:2]([N:33]3[CH2:32][CH2:31][N:30]([C:28]([O:27][CH2:25][CH3:26])=[O:29])[CH2:35][CH2:34]3)[S:3][CH:4]=2)[CH:12]=[CH:11][CH:10]=[CH:9][CH:8]=1

Participants

Conditions

Temperature: 100 °C

Procedure

A solution of the mixture of 2-bromo-4-phenylthiophene and 2-bromo-3-phenylthiophene (6.00 g, 25.0 mmol), 1-ethoxycarbonylpiperazine (3.96 g, 25.0 mmol), sodium tert-butoxide (3.48 g, 36.2 mmol), 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (468 mg, 0.750 mmol) and tris(dibenzylideneacetone)dipalladium (0) (544 mg, 0.594 mmol) in toluene (50 ml) was stirred at 100° C. for 48 hours. Insolubles were filtered off and the filtrate was concentrated. The residue was purified by silica gel column chromatography (hexane:ethyl acetate=9:1) to obtain ethyl 4-(4-phenyl-2-thienyl)piperazine-1-carboxylate (365 mg, 4.61%) as an oil.

Workup

filtrationInsolubles were filtered off
concentrationthe filtrate was concentrated
customThe residue was purified by silica gel column chromatography (hexane:ethyl acetate=9:1)

Sources & evidence

ORD record: ord-169fc0787d084934b73cbc57dbd58190
Source dataset: uspto-grants-2010_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07851473B2

Reaction notes

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