5-Methoxy-2-thiopheneglyoxylic acid ethyl ester → 5-Methoxy-2-thiopheneglyoxylic acid

HRID 838887Notes

Reaction equation

HRID 838887 reaction equation
C([O:3][C:4](=[O:14])[C:5]([C:7]1[S:8][C:9]([O:12][CH3:13])=[CH:10][CH:11]=1)=[O:6])C>[OH-].[K+].CO.O>[CH3:13][O:12][C:9]1[S:8][C:7]([C:5](=[O:6])[C:4]([OH:14])=[O:3])=[CH:11][CH:10]=1

Participants

5

Reactant 1

HCID 544362655-Methoxy-2-thiopheneglyoxylic acid ethyl ester

Product 1

HCID 203151145-Methoxy-2-thiopheneglyoxylic acid

Reagents, catalysts & solvents 3

HCID 887MethanolSolventHCID 962WaterSolventHCID 14797Potassium HydroxideSolvent

Procedure

The latter ester (25 g) is stirred in 500 ml of 5% aqueous KOH in methanol (250 ml H2O, 250 ml CH3OH, 25 g KOH) at room temperature for about 2 hr. The mixture is diluted with water and extracted several times with ether to remove all neutral material. The aqueous fraction is cooled with crushed ice, acidified with 10% HCl and extracted with ether. The ether extract is washed with water and brine, dried (MgSO4) and concentrated to give 5-methoxy-2-thiopheneglyoxylic acid (3; X1 = CH3O, X2 and X3 = H and R10 = H); γmaxCHCl3 3000, 1630, 1625, 1530 cm-1.

Workup

  1. extractionextracted several times with ether
  2. customto remove all neutral material
  3. temperatureThe aqueous fraction is cooled with crushed ice
  4. extractionextracted with ether
  5. extractionThe ether extract
  6. washis washed with water and brine
  7. dry with materialdried (MgSO4)
  8. concentrationconcentrated

Sources & evidence

ORD record
ord-20915f32b8f24b3aad800512cff4143f
Source dataset
uspto-grants-1978_06
Patent number
US04093628

Reaction notes

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