Water → tert-Butyl 4-(thiazol-2-yl)piperazine-1-carboxylate

HRID 1592881Notes

Reaction equation

HRID 1592881 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.Br[C:15]1[S:16][CH:17]=[CH:18][N:19]=1.C([O-])([O-])=O.[K+].[K+].O>CCO>[S:16]1[CH:17]=[CH:18][N:19]=[C:15]1[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

6

Reactant 4

HCID 962WaterHCID 11430Potassium CarbonateHCID 764302-BromothiazoleHCID 143452tert-Butyl piperazine-1-carboxylate

Product 1

HCID 21925505tert-Butyl 4-(thiazol-2-yl)piperazine-1-carboxylate

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

A mixture of 5 g of tert-butyl 1-piperazinecarboxylate, 4.4 g of 2-bromo-1,3-thiazole and 7.4 g of K2CO3 in 50 ml of EtOH is heated at reflux for 4 days. Water is added to the reaction mixture, the EtOH is evaporated under vacuum, the resulting aqueous phase is extracted with AcOEt, the organic phase is washed with saturated K2CO3 solution and with saturated NaCl solution and dried over Na2SO4 and the solvent is evaporated under vacuum. The residue is chromatographed on silica gel, eluting with a DCM/MeOH (98/2; v/v) mixture. This gives 5 g of the expected product following cold precipitation from a DCM/hexane mixture and isolation with suction; m.p.=114-116° C.

Workup

  1. temperatureis heated
  2. temperatureat reflux for 4 days
  3. customthe EtOH is evaporated under vacuum
  4. extractionthe resulting aqueous phase is extracted with AcOEt
  5. washthe organic phase is washed with saturated K2CO3 solution and with saturated NaCl solution
  6. dry with materialdried over Na2SO4
  7. customthe solvent is evaporated under vacuum
  8. customThe residue is chromatographed on silica gel
  9. washeluting with a DCM/MeOH (98/2; v/v) mixture
  10. customprecipitation from a DCM/hexane mixture and isolation with suction

Sources & evidence

ORD record
ord-5883a35b999f4daeb454c339c68daaf2
Source dataset
uspto-grants-2007_11
Patent number
US07294628B2

Reaction notes

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