Cesium carbonate → 3-Bromo-5-(1-oxo-6,7,8,9-tetrahydropyrazino[1,2-a]indol-2(1H)-yl)isonicotinaldehyde

HRID 592627Notes

Reaction equation

Br[C:2]1[CH:9]=[N:8][CH:7]=[C:6]([Br:10])[C:3]=1[CH:4]=[O:5].[C:11]1(=[O:24])[C:16]2=[CH:17][C:18]3[CH2:19][CH2:20][CH2:21][CH2:22][C:23]=3[N:15]2[CH:14]=[CH:13][NH:12]1.C(=O)([O-])[O-].[Cs+].[Cs+].COC1C2C(=C3C(=CC=2)C(OC)=CC=N3)N=CC=1>[Cu]I.O1CCOCC1>[Br:10][C:6]1[CH:7]=[N:8][CH:9]=[C:2]([N:12]2[CH:13]=[CH:14][N:15]3[C:23]4[CH2:22][CH2:21][CH2:20][CH2:19][C:18]=4[CH:17]=[C:16]3[C:11]2=[O:24])[C:3]=1[CH:4]=[O:5]

Participants

Conditions

Temperature: 100 °C

Procedure

A 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer and reflux condenser was charged with 1,4-dioxane (15 mL), 3,5-dibromoisonicotinaldehyde (604 mg, 2.28 mmol), 6,7,8,9-tetrahydropyrazino[1,2-a]indol-1(2H)-one (142 mg, 0.76 mmol) and cesium carbonate (485 mg, 1.5 mmol). CuI (143 mg, 0.76 mmol) and 4,7-dimethoxy-1,10-phenanthroline (127 mg, 0.52 mmol) were added, and the reaction mixture was heated at 100° C. for 5 h. After this time, the reaction was cooled to room temperature. It was then filtered and the filtrate was concentrated under reduced pressure. The residue was purified on flash column eluting with EtOAC/PE (1:2) to afford 126a (100 mg, 35%) as a yellow solid. MS: [M+H]+ 372.

Workup

customA 100-mL single-neck round-bottomed flask equipped with a magnetic stirrer
temperaturereflux condenser
temperatureAfter this time, the reaction was cooled to room temperature
filtrationIt was then filtered
concentrationthe filtrate was concentrated under reduced pressure
customThe residue was purified on flash column
washeluting with EtOAC/PE (1:2)

Sources & evidence

ORD record: ord-2a41258ed71e45c1954a8352c0828835
Source dataset: uspto-grants-2016_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09238655B2

Reaction notes

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