Ethyl bromopyruvate → 2-Phenylthiazole-4-carboxylic acid methyl ester

HRID 1424332Notes

Reaction equation

HRID 1424332 reaction equation
[C:1](=[S:9])([NH2:8])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.Br[CH2:11][C:12](=O)[C:13]([O:15][CH2:16]C)=[O:14]>C1COCC1>[C:2]1([C:1]2[S:9][CH:11]=[C:12]([C:13]([O:15][CH3:16])=[O:14])[N:8]=2)[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1

Participants

4

Reactant 2

HCID 66144Ethyl bromopyruvateHCID 683563Thiobenzamide

Product 1

HCID 111835862-Phenylthiazole-4-carboxylic acid methyl ester

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

A solution of benzothioamide (4.0 g, 29.2 mmol) in THF (80 mL) was treated dropwise with ethyl bromopyruvate (7.6 g, 39 mmol) and heated at reflux for 18 hours. The reaction was then concentrated under vacuum, diluted with ethyl acetate, washed with water (1×), brine (1×) and dried over anhydrous magnesium sulfate. The residue obtained after concentration was purified by silica gel chromatography (4.5×11 cm, 20% AcOEt/toluene), followed by a second purification with 20% AcOEt/hexane. The title material was obtained after concentration as a yellow oil (5.25, 77%). 1H NMR (CDCl3, 400 MHz): 8.14 (s, 1H) 8.00 (m, 2H) 7.46-7.42 (m, 3H) 4.43 (q, J=7.0 Hz, 2H) 1.42 (t, J=7.3 Hz, 3H).

Workup

  1. temperatureheated
  2. temperatureat reflux for 18 hours
  3. concentrationThe reaction was then concentrated under vacuum
  4. additiondiluted with ethyl acetate
  5. washwashed with water (1×), brine (1×)
  6. dry with materialdried over anhydrous magnesium sulfate
  7. customThe residue obtained
  8. concentrationafter concentration
  9. customwas purified by silica gel chromatography (4.5×11 cm, 20% AcOEt/toluene)
  10. customfollowed by a second purification with 20% AcOEt/hexane

Sources & evidence

ORD record
ord-00109df1b7d24241a720dd7da09fc5d4
Source dataset
uspto-grants-2015_01
Patent number
US08927688B2

Reaction notes

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