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

Participants

Reaction Conditions

Reaction Steps

A stirred solution of 25.0 g of methyl 8-(2-furyl)-8-methoxy-5-octynoate, 5.52 g of sodium dihydrogen phosphate monohydrate, 45.6 g of 86% phosphoric acid, 300 ml of dioxane and 200 ml of water was heated under reflux for 44 hours. The resulting solution, which contained a mixture of the 3- and 4-hydroxy isomers, was cooled to 50° C. and treated dropwise with 15 ml of concentrated sulfuric acid. This solution was stirred under reflux for 12 hours, cooled and partitioned with brine and ether. The organic layer was separated, washed with brine, dried and concentrated. The resulting oil was chromatographed on a silica gel column with chloroform progressively enriched in ether. The appropriate fractions were combined and concentrated, giving 6.4 g of the desired product which was recrystallized from ether, giving tan crystals, mp 65°-71° C.

Provenance & Evidence