Sulfuric Acid → 5-(Carbomethoxy)-2,4,5,6-tetrahydro-cyclopenta[c]thiophene

HRID 22526Notes

Reaction equation

HRID 22526 reaction equation
[C:1]([CH:4]1[CH2:11][C:7]2=[CH:8][S:9][CH:10]=[C:6]2[CH2:5]1)([OH:3])=[O:2].[CH3:12]OC(OC)(C)C.S(=O)(=O)(O)O>CO>[C:1]([CH:4]1[CH2:11][C:7]2=[CH:8][S:9][CH:10]=[C:6]2[CH2:5]1)([O:3][CH3:12])=[O:2]

Participants

5

Reactant 3

HCID 1118Sulfuric AcidHCID 64952,2-DimethoxypropaneHCID 158144134H,5H,6H-cyclopenta[c]thiophene-5-carboxylic acid

Product 1

HCID 158144145-(Carbomethoxy)-2,4,5,6-tetrahydro-cyclopenta[c]thiophene

Reagents, catalysts & solvents 1

HCID 887MethanolSolvent

Procedure

Dissolve 5-(carboxy)-2,4,5,6-tetrahydrocyclopenta[c]thiophene (3.95 g, 23.5 mmol) in methanol (60 mL) and treat with dimethoxypropane (5.8 mL, 47 mmol) and sulfuric acid (0.8 mL). Stir at room temperature for 1 day. Evaporate the solvent in vacuo, dilute with methylene chloride (75 mL) and wash with saturated sodium hydrogen carbonate (35 mL). Extract the aqueous phase with methylene chloride (30 mL), wash combined organics with brine (30 mL) and dry (Na2SO4). Evaporate the solvent in vacuo and pass through a plug of silica gel to give 5-(carbomethoxy)-2,4,5,6-tetrahydro-cyclopenta[c]thiophene.

Workup

  1. customEvaporate the solvent in vacuo
  2. additiondilute with methylene chloride (75 mL)
  3. washwash with saturated sodium hydrogen carbonate (35 mL)
  4. extractionExtract the aqueous phase with methylene chloride (30 mL)
  5. washwash
  6. dry with materialdry (Na2SO4)
  7. customEvaporate the solvent in vacuo and pass through a plug of silica gel

Sources & evidence

ORD record
ord-08dab0427af14ec18c8c42dfbec30973
Source dataset
uspto-grants-1995_06
Patent number
US05428158

Reaction notes

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