5-Bromothiophene-2-carbaldehyde → Tert-butyl 4-(5-formylthiophen-2-yl)piperazine-1-carboxylate

HRID 1911317Notes

Reaction equation

Br[C:2]1[S:6][C:5]([CH:7]=[O:8])=[CH:4][CH:3]=1.[N:9]1([C:15]([O:17][C:18]([CH3:21])([CH3:20])[CH3:19])=[O:16])[CH2:14][CH2:13][NH:12][CH2:11][CH2:10]1.C(N(C(C)C)C(C)C)C>CS(C)=O>[CH:7]([C:5]1[S:6][C:2]([N:12]2[CH2:11][CH2:10][N:9]([C:15]([O:17][C:18]([CH3:21])([CH3:20])[CH3:19])=[O:16])[CH2:14][CH2:13]2)=[CH:3][CH:4]=1)=[O:8]

Participants

Conditions

Temperature: 130 °C

Procedure

A mixture of 5-bromothiophene-2-carboxaldehyde (3.82 g, 20.0 mmol), tert-butyl piperazine-1-carboxylate (4.1 g, 22.0 mmol), N-ethyl-N,N-diisopropylamine (7.0 ml, 40.0 mmol) and dimethylsulphoxide (5.0 ml) were stirred at 130° C. under an atmosphere of nitrogen for 18 h. The cooled mixture was partitioned between ethyl acetate and water. The organics were washed with water, brine, dried over magnesium sulphate and evaporated. The resultant dark red solid was purified by silica column chromatography, eluting with dichloromethane followed by ethyl acetate/dichloromethane (15%) to give tert-butyl 4-(5-formylthien-2-yl)piperazine-1-carboxylate (4.3 g, 73%).

Workup

customThe cooled mixture was partitioned between ethyl acetate and water
washThe organics were washed with water, brine
dry with materialdried over magnesium sulphate
customevaporated
customThe resultant dark red solid was purified by silica column chromatography
washeluting with dichloromethane

Sources & evidence

ORD record: ord-79e16d86aada4d1a8cc4d74715806896
Source dataset: uspto-grants-2013_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08604022B2

Reaction notes

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