Sulfuric Acid → 7-(4-Hydroxycyclopent-2-en-1-on-2-yl)-5-heptynoic acid

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Reaction Conditions

Reaction Steps

A stirred mixture of 7.1 g of 2,5-dihydro-2,5-di- methoxy-2-(8,8,8-trimethoxy-3-octynyl)furan, 2.76 g of sodium dihydrogen phosphate monohydrate, 140 mg of disodium hydrogen phosphate, 60 ml of dioxane and 40 ml of water was boiled under reflux for 19 hours, then cooled to 50° C. and treated dropwise with 4.1 ml of concentrated sulfuric acid. The resulting solution was boiled under reflux for 12 hours, cooled and partitioned with ether and brine. The ether layer was separated, washed with brine, dried and concentrated, giving 5.0 g of crude 7-(4-hydroxycyclopent-2-en-1-on-2-yl)-5-heptynoic acid. This crude product was dissolved in 40 ml of pyridine and the stirred solution treated at 0° to 10° C. with 10.5 ml of hexamethyldisilizane followed by 6.3 ml of chlorotrimethylsilane. The resulting mixture was stirred at 25° C. for 3 hours and then concentrated to dryness at 30° C. The residue was extracted with hexane, the extract filtered through diatomaceous earth and concentrated. The residue was distilled at 0.11 mm on a Kugelrohr at 155°-170° C., giving 1.66 g of the desired compound as an oil.

Provenance & Evidence