Potassium Carbonate → tert-Butyl 4-(2-fluoroethyl)piperazine-1-carboxylate

HRID 419361Notes

Reaction equation

HRID 419361 reaction equation
[N:1]1([C:7]([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8])[CH2:6][CH2:5][NH:4][CH2:3][CH2:2]1.C([O-])([O-])=O.[K+].[K+].[F:20][CH2:21][CH2:22]I>C1COCC1>[F:20][CH2:21][CH2:22][N:4]1[CH2:5][CH2:6][N:1]([C:7]([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8])[CH2:2][CH2:3]1

Participants

5

Reactant 3

HCID 11430Potassium CarbonateHCID 69804Ethane, 1-fluoro-2-iodo-HCID 143452tert-Butyl piperazine-1-carboxylate

Product 1

HCID 21082715tert-Butyl 4-(2-fluoroethyl)piperazine-1-carboxylate

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
85 °C

Procedure

In a sealed tube, 1,1-dimethylethyl 1-piperazinecarboxylate (10.0 g, 54.0 mmol) was dissolved in 100 mL of THF. K2CO3 (11.2 g, 81.0 mmol) and 1-fluoro-2-iodoethane (11.3 g, 64.8 mmol) were added and the reaction was heated to 85° C. for 16 h. The reaction was cooled to rt and solids were filtered and washed with DCM. The filtrate was concentrated in vacuo being careful not to heat the H2O bath past 30° C. The resulting crude product, 1,1-dimethylethyl 4-(2-fluoroethyl)-1-piperazinecarboxylate was carried on to the next step without further purification. 1H NMR (400 MHz, DMSO-d6) δ ppm 4.48 (dt, JHF=47.8 Hz, J=4.9 Hz, 2H), 3.24-3.28 (m, 4H), 2.57 (dt, JHF=28.7, J=4.9 Hz, 2H), 2.31-2.36 (m, 4H), 1.34 (s, 9H).

Workup

  1. temperatureThe reaction was cooled to rt
  2. filtrationsolids were filtered
  3. washwashed with DCM
  4. concentrationThe filtrate was concentrated in vacuo
  5. temperatureto heat the H2O bath past 30° C
  6. customThe resulting crude product, 1,1-dimethylethyl 4-(2-fluoroethyl)-1-piperazinecarboxylate was carried on to the next step without further purification

Sources & evidence

ORD record
ord-4902982dbb5f477aad256244277cc050
Source dataset
uspto-grants-2012_01
Patent number
US08093239B2

Reaction notes

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