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

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Reaction Steps

Dissolve 5-(carboxy)-2,4,5,6-tetrahydro-cyclopenta[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 6 days. 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.

Provenance & Evidence