Lithium Hydroxide → 5-methyl-4-phenyl-2-thiophenecarboxylic acid

HRID 552270Notes

Reaction equation

HRID 552270 reaction equation
[SH:1][CH2:2][C:3]([O:5]CC)=[O:4].[Na].Cl[C:10]([CH3:20])=[C:11]([C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1)[CH:12]=O.[Li+].[OH-]>C(O)C>[CH3:20][C:10]1[S:1][C:2]([C:3]([OH:5])=[O:4])=[CH:12][C:11]=1[C:14]1[CH:19]=[CH:18][CH:17]=[CH:16][CH:15]=1

Participants

6

Reactant 4

HCID 3939Lithium HydroxideHCID 12185Ethyl ThioglycolateHCID 5360545SodiumHCID 58700835HCID 58700835, compound

Product 1

HCID 8219265-methyl-4-phenyl-2-thiophenecarboxylic acidYield 41.4%

Reagents, catalysts & solvents 1

HCID 702EthanolSolvent

Procedure

Ethyl 2-mercaptoacetate (5.92 g, 49.3 mmol) is added to a freshly prepared solution of sodium (1.2 g, 50 mmol) in ethanol (50 mL). To this solution 3-chloro-2-phenyl-but-2-enal (8.90 g, 49.3 mmol) is added and the mixture is stirred at rt for 16 h, then at 70° C. for 2 h. A 2 N aq. solution of LiOH (30 mL) is added and stirring is continued at 70° C. for 2 h. The ethanol is removed in vacuo, the remaining mixture is diluted with water and extracted with DCM. The aq. phase is acidified with aq. HCl and extracted with diethyl ether. The solvent of the ether phase is evaporated, the residue is suspended in acetonitrile, filtered and washed with additional acetonitrile and dried to give 5-methyl-4-phenyl-thiophene-2-carboxylic acid (4.45 g) as a yellow powder, LC-MS: tR=0.92 min, [M+1+MeCN]+=260.13; 1H NMR (CDCl3): δ 7.84 (s, 1H), 7.46-7.33 (m, 5H), 2.55 (s, 3H).

Workup

  1. waitat 70° C. for 2 h
  2. stirringstirring
  3. waitis continued at 70° C. for 2 h
  4. customThe ethanol is removed in vacuo
  5. additionthe remaining mixture is diluted with water
  6. extractionextracted with DCM
  7. extractionextracted with diethyl ether
  8. customThe solvent of the ether phase is evaporated
  9. filtrationfiltered
  10. washwashed with additional acetonitrile
  11. customdried

Sources & evidence

ORD record
ord-de7d74a3aefc4909accc8d44eec3c2e9
Source dataset
uspto-grants-2011_05
Patent number
US07951794B2

Reaction notes

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