Piperazine → 4-Methyl-2-piperazin-1-yl-quinoline

HRID 1772214Notes

Reaction equation

Cl[C:2]1[CH:11]=[C:10]([CH3:12])[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[N:3]=1.[NH:13]1[CH2:18][CH2:17][NH:16][CH2:15][CH2:14]1.C(=O)([O-])[O-].[K+].[K+]>CN(C)C=O>[CH3:12][C:10]1[C:9]2[C:4](=[CH:5][CH:6]=[CH:7][CH:8]=2)[N:3]=[C:2]([N:13]2[CH2:18][CH2:17][NH:16][CH2:15][CH2:14]2)[CH:11]=1

Participants

Conditions

Temperature: 140 °C

Procedure

To a solution of 2-chloro-4-methylquinoline (2 g, 11 mmol) in N,N-dimethylformamide (40 ml) was added piperazine (4.86 g, 56.4 mmol, 5 eq) and potassium carbonate (2.34 g, 16.8 mmol, 1.5 eq). The mixture was stirred overnight at 140° C., quenched by the addition of water (200 ml), and extracted with ethyl acetate (3×100 ml). The organic layers were combined and washed with saturated aqueous sodium chloride (200 ml). The ethyl acetate solution was dried over anhydrous sodium sulfate, filtered, and concentrated under vacuum. The crude material was purified by silica gel chromatography using 1-10% methanol in dichloromethane to elute. The product-containing fractions were combined and concentrated to afford 4-methyl-2-(piperazin-1-yl)quinoline as colorless oil (2.2 g, 86%); (ES, m/z) [M+H]+ 228; 1H NMR (300 MHz, CDCl3): δ 7.70-7.78 (m, 2H), 7.50-7.55 (t, J=7.5 Hz, 1H), 7.22-7.27 (t, J=6.9 Hz, 1H), 6.83 (s, 2H), 3.70-3.73 (t, J=4.8 Hz, 1H), 3.00-3.03 (t, J=5.1 Hz, 1H), 2.59 (s, 3H).

Workup

customquenched by the addition of water (200 ml)
extractionextracted with ethyl acetate (3×100 ml)
washwashed with saturated aqueous sodium chloride (200 ml)
dry with materialThe ethyl acetate solution was dried over anhydrous sodium sulfate
filtrationfiltered
concentrationconcentrated under vacuum
customThe crude material was purified by silica gel chromatography
washto elute
concentrationconcentrated

Sources & evidence

ORD record: ord-53b5be16f72a444c8c81c1a453b9d881
Source dataset: uspto-grants-2016_02
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09249102B2

Reaction notes

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