Lithium Hydroxide → 4-Methyl-5-(2-methyl-propenyl)-thiophene-2-carboxylic acid

HRID 1094291Notes

Reaction equation

HRID 1094291 reaction equation
C[O:2][C:3]([C:5]1[S:6][C:7]([CH:11]=[C:12]([CH3:14])[CH3:13])=[C:8]([CH3:10])[CH:9]=1)=[O:4].[Li+].[OH-]>CO.C(OCC)C>[CH3:10][C:8]1[CH:9]=[C:5]([C:3]([OH:4])=[O:2])[S:6][C:7]=1[CH:11]=[C:12]([CH3:14])[CH3:13]

Participants

5

Reactant 2

HCID 3939Lithium HydroxideHCID 666369304-Methyl-5-(2-methyl-propenyl)-thiophene-2-carboxylic acid methyl ester

Product 1

HCID 592020274-Methyl-5-(2-methyl-propenyl)-thiophene-2-carboxylic acidYield 80.1%

Reagents, catalysts & solvents 2

HCID 887MethanolSolventHCID 3283Diethyl EtherSolvent

Procedure

A solution of 4-methyl-5-(2-methyl-propenyl)-thiophene-2-carboxylic acid methyl ester (4.08 g, 19.4 mmol) in methanol (33 mL) is treated with 2 N aq. LiOH solution (10 mL). The mixture is stirred at rt for 2 h, then at 45° C. for 3 h. The reaction mixture is diluted with diethyl ether. The org. layer is separated and extracted with water. The combined aq. phase is acidified with 1 M aq. HCl, and extracted twice with diethyl ether. The combined second org. extracts are dried over MgSO4, filtered and concentrated to give 4-methyl-5-(2-methyl-propenyl)-thiophene-2-carboxylic acid (3.05 g) as an off-white solid; LC-MS: tR=0.92 min, [M+1]+=196.98.

Workup

  1. waitat 45° C. for 3 h
  2. customlayer is separated
  3. extractionextracted with water
  4. extractionextracted twice with diethyl ether
  5. dry with materialextracts are dried over MgSO4
  6. filtrationfiltered
  7. concentrationconcentrated

Sources & evidence

ORD record
ord-f5f70b59097a44b99b07caef04efedf4
Source dataset
uspto-grants-2012_03
Patent number
US08133910B2

Reaction notes

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