Sodium Carbonate → Ethyl 1,3-thiazole-2-carboxylate

HRID 501225Notes

Reaction equation

HRID 501225 reaction equation
C[Si](C)(C)[C:3]1[S:4][CH:5]=[CH:6][N:7]=1.Cl[C:11]([O:13][CH2:14][CH3:15])=[O:12].C(=O)([O-])[O-].[Na+].[Na+]>C1(C)C=CC=CC=1>[S:4]1[CH:5]=[CH:6][N:7]=[C:3]1[C:11]([O:13][CH2:14][CH3:15])=[O:12]

Participants

5

Reactant 3

HCID 10340Sodium CarbonateHCID 10928Ethyl chloroformateHCID 5884532-Trimethylsilylthiazole

Product 1

HCID 13032471Ethyl 1,3-thiazole-2-carboxylateYield 51.1%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent2×

Conditions

Temperature
25 °C

Procedure

10 g (63.7 mmol) of 2-trimethylsilylthiazole (1) and 435 ml of toluene are placed in a 2-liter round-bottomed flask under argon. The reaction mixture is stirred and cooled using an ice bath, and, when the temperature has reached about 8° C., a solution of 12.2 ml (0.128 mol) of ethyl chloroformate in 500 ml of toluene is added. Once all the solution has been added, the mixture is left for about 10 minutes and then warmed to 25° C. After stirring for 20 hours, 200 ml of aqueous sodium carbonate solution are added and the mixture is stirred for 30 minutes. After separation of the phases by settling, the organic phase is washed with 200 ml of saturated aqueous sodium chloride solution. After drying over magnesium sulfate, the organic phase is concentrated to dryness under reduced pressure. The residue is purified by flash chromatography (msilica=200 g; eluent: 60/40 cyclohexane/ethyl acetate). 5.12 g of ethyl 2-thiazolecarboxylate (2) are thus obtained in the form of a greenish liquid that crystallizes. Rf(50/50 cyclohexane/ethyl acetate)=0.52.

Workup

  1. temperaturecooled
  2. customhas reached about 8° C.
  3. additionOnce all the solution has been added
  4. stirringAfter stirring for 20 hours
  5. stirringthe mixture is stirred for 30 minutes
  6. customAfter separation of the phases
  7. washthe organic phase is washed with 200 ml of saturated aqueous sodium chloride solution
  8. dry with materialAfter drying over magnesium sulfate
  9. concentrationthe organic phase is concentrated to dryness under reduced pressure
  10. customThe residue is purified by flash chromatography (msilica=200 g; eluent: 60/40 cyclohexane/ethyl acetate)

Sources & evidence

ORD record
ord-d6e9e576ec604e818d99a607b3710f3d
Source dataset
uspto-grants-2010_08
Patent number
US07772261B2

Reaction notes

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