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

HRID 1092016Notes

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-a9fc2d5b627f45e1b056a3d71487c00f
Source dataset: uspto-grants-2012_03
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08129391B2

Reaction notes

Loading…