2,2-Dimethyl-4-oxo-tetrahydro-thiopyran-3-carboxylic acid methyl ester → 2,2-Dimethyltetrahydro-4h-thiopyran-4-one

HRID 387278Notes

Reaction equation

HRID 387278 reaction equation
COC([CH:5]1[C:10](=[O:11])[CH2:9][C:8]([CH3:13])([CH3:12])[S:7][CH2:6]1)=O.COC(C1C(=O)CCSC1(C)C)=O>OS(O)(=O)=O>[CH3:12][C:8]1([CH3:13])[CH2:9][C:10](=[O:11])[CH2:5][CH2:6][S:7]1

Participants

4

Reactant 2

HCID 593326592,2-Dimethyl-4-oxo-tetrahydro-thiopyran-3-carboxylic acid methyl esterHCID 593327336,6-Dimethyl-4-oxo-tetrahydro-thiopyran-3-carboxylic acid methyl ester

Product 1

HCID 2875642,2-Dimethyltetrahydro-4h-thiopyran-4-oneYield 17.7%

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Procedure

The mixture of 6,6-Dimethyl-4-oxo-tetrahydro-thiopyran-3-carboxylic acid methyl ester and 2,2-Dimethyl-4-oxo-tetrahydro-thiopyran-3-carboxylic acid methyl ester (42 g) in 10% aq. H2SO4 solution (1000 mL) was heated at reflux for 70 h. Then the mixture was extracted with Et2O (3×300 mL), the combined organic layer was washed with sat. NaHCO3 (120 mL) and brine (120 mL), dried over Na2SO4 and evaporated under vacuum to give the title compound as a white solid (5.3 g, 17.7%, two steps).

Workup

  1. temperaturewas heated
  2. temperatureat reflux for 70 h
  3. extractionThen the mixture was extracted with Et2O (3×300 mL)
  4. washthe combined organic layer was washed with sat. NaHCO3 (120 mL) and brine (120 mL)
  5. dry with materialdried over Na2SO4
  6. customevaporated under vacuum

Sources & evidence

ORD record
ord-bffdac0aa5724d59a1a4a7478ba2c725
Source dataset
uspto-grants-2013_02
Patent number
US08372875B2

Reaction notes

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