Cesium carbonate → HCID 44546388, compound

HRID 221219Notes

Reaction equation

[OH:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[N:8]1[CH2:13][CH2:12][N:11]([C:14]([O:16][C:17]([CH3:20])([CH3:19])[CH3:18])=[O:15])[CH2:10][CH2:9]1.C(=O)([O-])[O-].[Cs+].[Cs+].Br[CH2:28][CH2:29][CH2:30][C:31]([O:33][CH2:34][CH3:35])=[O:32]>CN(C=O)C.C(OCC)(=O)C>[CH2:34]([O:33][C:31](=[O:32])[CH2:30][CH2:29][CH2:28][O:1][C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][C:3]=1[N:8]1[CH2:13][CH2:12][N:11]([C:14]([O:16][C:17]([CH3:20])([CH3:19])[CH3:18])=[O:15])[CH2:10][CH2:9]1)[CH3:35]

Participants

Conditions

Temperature: 70 °C

Procedure

To a stirred solution of tert-butyl 4-(2-hydroxyphenyl)-piperazine 20 (1 g, 0.0035 mol.) and cesium carbonate (2.34 g, 0.0071 mol.) in 5 mL of DMF anhydrous was added a solution of ethyl 4-bromobutanoate (6a) at rt. The resulting mixture was heated at 70° C. overnight (12 h). The progress of the reaction was monitored by thin layer chromatography (TLC). After the reaction was complete, the reaction mixture was diluted with 25 mL of ethyl acetate and filtered to remove cesium carbonate. The filtrate was washed with saturated aqueous NaHCO3 solution, dried over Na2SO4 and evaporated to give tert-butyl 4-(2-(4-ethoxy-4-oxobutoxy)phenyl)-piperazine-1carboxylate 21a which was purified by silica gel chromatography using a gradient elution of ethyl acetate and hexane. Colorless oil (1.1 g, 78%). 1H NMR (400 MHz, CDCl3): δ 1.25 (t, J=6.4 Hz, 3H); 1.45 (s, 9H); 2.14 (q, J=7.2 Hz, 2H); 2.53 (t, J=7.2Hz, 2H); 3.00 (br s, 4H); 3.58 (br s, 4H); 4.04 (t, J=6.4 Hz, 2H); 4.12 (q, J=6.4 Hz, 2H); 6.84-6.97 (m, 4H).

Workup

filtrationfiltered
customto remove cesium carbonate
washThe filtrate was washed with saturated aqueous NaHCO3 solution
dry with materialdried over Na2SO4
customevaporated

Sources & evidence

ORD record: ord-f95c351a638a4f24a8beaaf4de5ce624
Source dataset: uspto-grants-2012_06
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08207163B2

Reaction notes

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