Sulfuric acid magnesium salt (1:1) → Ethyl 2-isopropylthiazole-4-carboxylate

HRID 443114Notes

Reaction equation

HRID 443114 reaction equation
[CH3:1][CH:2]([CH3:6])[C:3](=[S:5])[NH2:4].Br[CH2:8][C:9](=O)[C:10]([O:12][CH2:13][CH3:14])=[O:11].[O-]S([O-])(=O)=O.[Mg+2]>CC(C)=O>[CH:2]([C:3]1[S:5][CH:8]=[C:9]([C:10]([O:12][CH2:13][CH3:14])=[O:11])[N:4]=1)([CH3:6])[CH3:1]

Participants

5

Reactant 3

HCID 24083Sulfuric acid magnesium salt (1:1)HCID 66144Ethyl bromopyruvateHCID 109095072-Methylpropanethioamide

Product 1

HCID 10535999Ethyl 2-isopropylthiazole-4-carboxylateYield 86.4%

Reagents, catalysts & solvents 1

HCID 180AcetoneSolvent

Procedure

A solution of 2.35 g (23 mmol) of 2-methylpropane-thioamide and 2.89 ml (23 mmol) of ethyl bromopyruvate in 75 ml of acetone was treated with excess MgSO4 and heated at reflux for 2.5 h. The resulting mixture was allowed to cool, filtered, and concentrated in vacuo to an oil, which was taken up in chloroform, washed sequentially with aqueous NaHCO3 and brine, dried over Na2SO4, and concentrated. The residue was purified by chromatography on silica gel using chloroform as an eluent to provide 3.96 g (86%) of the desired compound, Rf 0.21 (chloroform) as an oil. 1H NMR (CDCl3) δ 1.41 (t, J=8 Hz, 3 H), 1.42 (d, J=7 Hz, 6 H), 3.43 (heptet, J=7 Hz, 1 H), 4.41 (q, J=8 Hz, 2 H), 8.05 (s, 1 H). Mass spectrum: (M+H)+ =200.

Workup

  1. temperatureheated
  2. temperatureat reflux for 2.5 h
  3. temperatureto cool
  4. filtrationfiltered
  5. concentrationconcentrated in vacuo to an oil, which
  6. washwashed sequentially with aqueous NaHCO3 and brine
  7. dry with materialdried over Na2SO4
  8. concentrationconcentrated
  9. customThe residue was purified by chromatography on silica gel

Sources & evidence

ORD record
ord-1604e45f9df2444e833fbc2ad3e6f4e5
Source dataset
uspto-grants-1999_04
Patent number
US05892052

Reaction notes

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